Abstract
Base isolation or seismic base isolation is an effective means for protection of structures, its contents and its occupants during the event of an earthquake. The principle of base isolation is vibration isolation. It decouples the building from damaging action of the earthquake. The isolator partially reflects and partially absorbs input seismic energy before it gets transmitted to the superstructure. Laminated Rubber Bearing Isolators are placed between the superstructure and foundation, which reduces the horizontal stiffness of the system. It thereby increases the time period of the structure and decreases the spectral acceleration of the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. Such type of isolators are used in practice in India, yet a proper design procedure based on IS code is unavailable. The paper presents design procedure for LRB adopting the procedure of IS 1893:2002 (Part-1) for earthquake resistant design of buildings. Design charts have been developed and presented in this paper which gives isolator diameter and rubber thickness as design outputs. The design procedure requires different input parameters like fundamental period and damping of the fixed base structure, axial load on the column, seismic zone, type of soil and shore hardness of rubber. These design charts enable the designer to easily arrive at the isolator parameters to achieve seismic isolation. Using the charts, case study has been done using SAP2000. Building displacement and acceleration are compared for model with and without base isolator. Comparative study of linear and non-linear base isolators has also been carried out. Linear and non-linear time history analysis has been done using El Centro earthquake.
Keywords: base isolation, laminated rubber bearing, IS Code, seismic protection, design charts, time history analysis, SAP2000
Seismic analysis of high damping rubber bearings for base isolationeSAT Journals
Abstract
Base isolation is a mechanism that provides earthquake resistance to the new structure. The base isolation system decouples the building from the horizontal ground motion induced by earthquake, and offers very stiff vertical components to the base level of the superstructure in connection to substructure (foundation). It shifts the fundamental lateral period, dissipates the energy in damping, and reduces the amount of the lateral forces that transferred to the building, inter-story drift, and the floor acceleration.
The work deals with modelling and finite element analysis of a high damping rubber bearing in ANSYS 12.0. A displacement controlled transient analysis was done to analyse the behaviour of the isolator during earthquakes.
Keywords: Base isolation, High damping rubber, Transient analysis
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Parametric study of response of an asymmetric building for various earthquake...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Seismic base isolation in strengthening an existing retrofitted masonry reinf...eSAT Journals
Abstract Seismic base isolation is a fast advancing technology in which the superstructure is isolated from the entire structure or from the substructure by means of rubber bearing isolators or frictional sliding isolators. The main aim of the base isolation technology is to isolate the structure from the harmful effects of the ground accelerations or earthquake excitations. In this paper, the procedure for the selection of the three ground motions is briefly explained and they are used in analyzing a masonry – reinforced concrete office building for the Internal Revenue Service in the Huating County of the Pingliang City in China. The structure is first analyzed with the PKPM software to ascertain the structural internal forces are within reasonable limits but because this software cannot be used to advance analysis in the area of base isolation, Sap 2000 is used to remodel the structure, analyze, then apply the seismic base isolation. This office building has been strengthened to be fortified against ultimate bearing capacity failure as it is an existing structure. The lead rubber bearing isolators, LRB 400, LRB 500 and LRB 600 are used to isolate the building model and results from the structural response are compared, first amongst the time histories and then between the enveloped time histories and the response spectrum. The floor joint accelerations are observed to be reduced and the joint velocities as well, whereas the floor joint displacements are increased. The response spectrum alone is seen to not be an enough ground acceleration parameter in a seismic analysis and design of this model; as such it is recommended to include time history analysis. The maximum percentage decrease in acceleration and velocity can be seen occurring in the response spectrum, namely, 85.82% and 59.76%, respectively. The maximum percentage increase in the displacement is also evident in the response spectrum, 57.59%. In the time histories, the maximum is seen in Ec County Y-direction for the acceleration reduction at a value of 60.57%; Delta artif records a maximum velocity reduction of 28.42% in the Y-direction and finally, the Delta artif X-direction also records a maximum displacement increment, at a value of 26.36%.
Seismic analysis of high damping rubber bearings for base isolationeSAT Journals
Abstract
Base isolation is a mechanism that provides earthquake resistance to the new structure. The base isolation system decouples the building from the horizontal ground motion induced by earthquake, and offers very stiff vertical components to the base level of the superstructure in connection to substructure (foundation). It shifts the fundamental lateral period, dissipates the energy in damping, and reduces the amount of the lateral forces that transferred to the building, inter-story drift, and the floor acceleration.
The work deals with modelling and finite element analysis of a high damping rubber bearing in ANSYS 12.0. A displacement controlled transient analysis was done to analyse the behaviour of the isolator during earthquakes.
Keywords: Base isolation, High damping rubber, Transient analysis
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Parametric study of response of an asymmetric building for various earthquake...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Seismic base isolation in strengthening an existing retrofitted masonry reinf...eSAT Journals
Abstract Seismic base isolation is a fast advancing technology in which the superstructure is isolated from the entire structure or from the substructure by means of rubber bearing isolators or frictional sliding isolators. The main aim of the base isolation technology is to isolate the structure from the harmful effects of the ground accelerations or earthquake excitations. In this paper, the procedure for the selection of the three ground motions is briefly explained and they are used in analyzing a masonry – reinforced concrete office building for the Internal Revenue Service in the Huating County of the Pingliang City in China. The structure is first analyzed with the PKPM software to ascertain the structural internal forces are within reasonable limits but because this software cannot be used to advance analysis in the area of base isolation, Sap 2000 is used to remodel the structure, analyze, then apply the seismic base isolation. This office building has been strengthened to be fortified against ultimate bearing capacity failure as it is an existing structure. The lead rubber bearing isolators, LRB 400, LRB 500 and LRB 600 are used to isolate the building model and results from the structural response are compared, first amongst the time histories and then between the enveloped time histories and the response spectrum. The floor joint accelerations are observed to be reduced and the joint velocities as well, whereas the floor joint displacements are increased. The response spectrum alone is seen to not be an enough ground acceleration parameter in a seismic analysis and design of this model; as such it is recommended to include time history analysis. The maximum percentage decrease in acceleration and velocity can be seen occurring in the response spectrum, namely, 85.82% and 59.76%, respectively. The maximum percentage increase in the displacement is also evident in the response spectrum, 57.59%. In the time histories, the maximum is seen in Ec County Y-direction for the acceleration reduction at a value of 60.57%; Delta artif records a maximum velocity reduction of 28.42% in the Y-direction and finally, the Delta artif X-direction also records a maximum displacement increment, at a value of 26.36%.
Dynamic Analysis of Soft Storey Frame with IsolatorsIJMTST Journal
Soft storey buildings are very common in Indian housing construction and the bottom storey is left open without walls for car parking. Past earthquakes showed that these kinds of buildings performed poor and the damages are also heavy. As the base isolation is a technique developed to prevent or minimize damage to building during an earthquake, this study focuses on the time history analysis of a soft-storey building with and without lead rubber isolator. The soft-storey building with and without isolator is analysed using Elcenrto earthquake data and the dynamic characteristics are compared.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
SEISMIC ISOLATION OF RC FRAMED STRUCTURE WITH AND WITHOUT INFILLSIAEME Publication
Earthquakes are the nature’s greatest hazard which cannot be exactly predicted by human
beings. Earthquake is a sudden movement of earth’s surface with the release of massive energy
in the form of seismic waves. There are so many methods to control the vibration of the
buildings like passive, active and hybrid control systems.[1] Base isolation is a passive control
system. In the present work, a (G+3) structure considering with and without infill’s subjected
to seismic force along with static gravity loads are analyzed using Response Spectrum Method
in ETABS-2015 package. From the study, the response of the structure obtained is time period,
base shear, story displacement and inter-story drifts and also the comparison is drawn for the
same parameters considering structure as bare and infill frames. The variation in percentage
of steel is also presented. It is found that the time period and story displacement increases
while base shear and story drifts gets reduces with the provision of effective base isolators.
Comparision of building for sesmic response by using base isolationeSAT Journals
Abstract
Throughout historic time Earthquakes are one of the natural hazards that occur due to sudden violent movement of earth’s
surface which causes damage to property, especially to man-made structures . Base isolation is one of the most powerful tools of
earthquake engineering pertaining to the passive structural vibration control technologies. The application of the base isolation
techniques to protect structures against damage from earthquake attacks has been considered as one of the most effective
approaches and has gained increasing acceptance during the last two decades. This paper present three dimensional nonlinear
time history analysis is performed on r/c building by the use of computer program SAP 2000 v12.0.0. The dynamic analysis of the
structure has been carried out and the performance of the building with and without isolator is studied. The main objective here is
to make seismic response control by providing Isolators and comparing between the fixed based and isolated base building.
Rubber bearing and Friction pendulum bearing are used
Keywords: Base Isolation; Seismic Response; Time History
SEISMIC PROTECTION OF RC FRAMES USING FRICTION DAMPERSIAEME Publication
The increasing infrastructural growth incurs large investments and large section of society
being served by them, it is necessary to make them safer against earthquakes and let people
feel confident in their structures. The need for structural response control has gained pace in
application around the globe. This paper discusses the use and effectiveness of one such
device, friction dampers, for response control of structures. In this paper a non-linear time
history analysis has been carried out on a 3D model of a 12 story RCC MRF building using 3-
directional synthetic accelerogram. Two different cases of building models with and without
friction dampers have been analyzed using ETABS. The response of the structure to seismic
excitation in terms of absolute maximum displacement and story drift has been compared.
Time history response plots have also been compared for various responses viz. roof
displacement and acceleration, base shear and story shear forces, along with the various
energy components and damping behavior. The results of the time history analysis are in close
conformation with previous investigations and represent the effectiveness of dampers in
improving the structural response as well as damping demand on structural systems.
SEISMIC RESPONSE OF UNSYMMETRIC BUILDING WITH OPTIMALLY PLACED FRICTION DAMPERSIAEME Publication
Conventional methods of seismic rehabilitation with concrete shear walls or steel bracing
are not considered suitable for some buildings as upgrades with these methods would have
required expensive and time consuming foundation work. Supplemental damping in
conjunction with appropriate stiffness offers an innovative and attractive solution for the
seismic rehabilitation of such structures. This paper deals with the use of friction damper as a
passive dissipative device in order to seismic retrofit of existing structures and discusses the
optimal placement criteria. To fulfill this objective, six storey and ten storey L-shaped
buildings have been modeled with five different damper location formats in SAP2000 subjected
to El Centro and Utterkashi earthquake records. Non-Linear Modal Time History Method has
been used for the analysis and base shear, joint displacement, member forces and hysteresis
energy has been compared to find out most optimal damper location format.
Seismic Performance of Reinforced Cement Concrete Structures with and Without...ijtsrd
Passive energy dissipation have been used so far to dissipate the unwanted energy due to earthquake and heavy wind actions. The complete failure of the structures that has occurred in the past due to catastrophic earthquakes may be avoided with the use of such devices. The study is concerned with the use of accordion metallic dampers that uses hysteretic energy to dissipate the unwanted energy due to earthquake. It consists of corrugated thin wall tubes installed as a brace connection in the frame. The axial deformation of the accordion damper enhances the lateral buckling capacity and results in maximum reduction of the damaging measures. The study emphasizes the use of such dampers and in depth analysis is performed by subjecting the building to base excitations in order to assess the nonlinear performance of the dampers installed in the building Rahul Tahilyani | Dilip Budhlani ""Seismic Performance of Reinforced Cement Concrete Structures with and Without Viscous Dampers"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30122.pdf
Paper Url : https://www.ijtsrd.com/engineering/civil-engineering/30122/seismic-performance-of-reinforced-cement-concrete-structures-with-and-without-viscous-dampers/rahul-tahilyani
Comparison of bracings and shear walls as seismic strengthening methods to bu...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Analysis of rc framed structures with central and partial openings in masonry...eSAT Journals
Abstract In Reinforced concrete frames the masonry infill walls are a common practice in countries like India, where the region is prone to seismic activity. In general, the masonry infill walls are treated as nonstructural element in structural analysis and only the contribution of its mass for is considered and it’s structural parameters like strength and stiffness is generally ignored in practice, such an approach may lead to an unsafe design. Infill walls resist lateral loads but because of the openings in the infill wall the resistance may slightly reduce. The IS code provisions do not provide guidelines for the analysis and design of RC frames with infill wall and for different percentage of openings. In this study, an office or residential building outer side central opening or outer side partial openings are used and analysis is carried for Bare Frame model, infill walls without opening, infill walls with outer periphery central opening and infill wall with outer periphery partial opening models. In ETABS software G+14 RC framed building models has been prepared, Equivalent Static Lateral force method, Response spectrum method has been performed for analysis as per IS 1893 : 2002 including p-delta effects. Storey displacement, Storey shear, Storey drift, with soft storey considering the effects of infill wall with central and partial openings are the parameters considered in this study. For modeling, the Equivalent diagonal strut method has been used to find out the width of Strut using FEMA 273 .The results for bare frame, infill wall, and infill wall with central and partial openings are discussed and conclusions are made. Keywords: Equivalent diagonal strut, stiffness, Drift limitation
A parametric study of x and v bracing industrial steel structureeSAT Journals
Abstract Severe earthquakes have an extremely low probability of occurrence during a structures life. If the earthquakes to be resisted by the structure elastically, it would require an expensive lateral load resisting system, which is not warranty. The structure may lose its aesthetic and functionality due to minor tremors and needs repairs; it will be a very unfavourable design. In addition to earthquake forces there may be wind or any vibrations which induce lateral loads in a structure. In our work we have taken only the earthquake load to find a system which balances the lateral loads and minimizes the displacements of the floors. With the literature review, it was founded that bracing in a structural system reduces the story drift and reduces the lateral force effect. To examine the performance of the bracings, bracing types like X and V bracings are considered and an analysis is performed in ETABS software. The results are studied, discussed and concluded for the best bracing system among both in our project. Keywords: Bracings, Time – History method
Comparison of Two Similar Buildings with and without Base IsolationIJARIIT
Reinforced concrete is a major construction material for civil infrastructure in current society.
Construction design has always preceded the development of structural design methodology. Dramatic collapse of
buildings has been observed after each disastrous earthquake, resulting in loss of life. To prevent such a loss Baseisolation
is used which enables a building to survive potentially devastating seismic impact by providing flexibility into
the connection between the building and the foundation. The mechanism of the base isolator increases the natural
period of the overall structure, and decreases its acceleration response to earthquake/seismic motion. A reinforced
concrete building with lead rubber bearing is used. The study analysis performed to check for the adequacy of the
base isolation against earthquake damage when compared to the conventional earthquake resistant design. A building
was analyzed using the equivalent lateral force method and response spectrum analysis as fixed base (FB) and as
isolated base (IB) with lead rubber bearing. The analysis represents a case study for reinforced concrete to show the
ultimate capacity of the selected bearing system, and to make a comparison for the difference between the isolated
base and the fixed base buildings. R esults show that the presence of the lead rubber bearing reduces significantly the
displacement, moment and shear generated for the same mode and hence the reinforcement required is also lesser
when compared to the traditional fixed based structure.
Eatrhquake response of reinforced cocrete multi storey building with base iso...eSAT Journals
Abstract A seismic base isolation is an earthquake resistant design method that is based on reducing the seismic demand and also the ductility demand. The basic concept of base isolation system is to increase the natural time period of the fixed base building and to protect the structure from the seismic effect. The main purpose of this work is to study the dynamic response of structure when subjected to different isolators. For this purpose, a three dimensional response spectrum analysis and time history analysis is performed using a commercial structural analysis software package called as SAP 2000 to study the influence of isolation damping on building. The main objective is to make a comparison between the fixed base building and various isolation systems such as friction pendulum isolator, lead rubber bearing (LRB) isolator and high damping rubber isolator, subjected to strong earthquakes to achieve an optimal design of the base isolation system. SAP 2000, a popular large scale explicit finite element analysis software used to stimulate the behavior of base isolated structure. In the present work, it was found that base isolation substantially increases the time period of structure and hence correspondingly reduces the base shear. The top displacement for fixed and isolated cases conspicuously shows the reduction in the case of isolated frame. The study shows that the bending moment and shear force values are reduced for base isolated frame when compared to fixed base building. From design consideration the steel requirement is reduced in base isolated structures when compared to fixed base building. Key Words: Isolators, SAP2000
ELASTOMERIC BASE ISOLATION SYSTEM FOR SEISMIC MITIGATION OF LOW-RISE STRUCTURESIAEME Publication
Seismic base isolation is a passive way of achieving seismic response control by introducing isolators between foundation and super structure. Isolator performs three functions: horizontal flexibility, energy dissipation and rigidity against normal lateral loads. Lead Rubber bearing isolators
performs these functions efficiently. By reducing the horizontal stiffness of the system, it increases the time period of the structure and decreases the spectral acceleration of the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. Such type of isolators are used
in practice in India, yet a proper design procedure based on IS code is unavailable. The paper presents design procedure for LRB adopting the procedure of IS 1893:2002 (Part-1) for earthquake resistant design of buildings.
Dynamic Analysis of Soft Storey Frame with IsolatorsIJMTST Journal
Soft storey buildings are very common in Indian housing construction and the bottom storey is left open without walls for car parking. Past earthquakes showed that these kinds of buildings performed poor and the damages are also heavy. As the base isolation is a technique developed to prevent or minimize damage to building during an earthquake, this study focuses on the time history analysis of a soft-storey building with and without lead rubber isolator. The soft-storey building with and without isolator is analysed using Elcenrto earthquake data and the dynamic characteristics are compared.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
SEISMIC ISOLATION OF RC FRAMED STRUCTURE WITH AND WITHOUT INFILLSIAEME Publication
Earthquakes are the nature’s greatest hazard which cannot be exactly predicted by human
beings. Earthquake is a sudden movement of earth’s surface with the release of massive energy
in the form of seismic waves. There are so many methods to control the vibration of the
buildings like passive, active and hybrid control systems.[1] Base isolation is a passive control
system. In the present work, a (G+3) structure considering with and without infill’s subjected
to seismic force along with static gravity loads are analyzed using Response Spectrum Method
in ETABS-2015 package. From the study, the response of the structure obtained is time period,
base shear, story displacement and inter-story drifts and also the comparison is drawn for the
same parameters considering structure as bare and infill frames. The variation in percentage
of steel is also presented. It is found that the time period and story displacement increases
while base shear and story drifts gets reduces with the provision of effective base isolators.
Comparision of building for sesmic response by using base isolationeSAT Journals
Abstract
Throughout historic time Earthquakes are one of the natural hazards that occur due to sudden violent movement of earth’s
surface which causes damage to property, especially to man-made structures . Base isolation is one of the most powerful tools of
earthquake engineering pertaining to the passive structural vibration control technologies. The application of the base isolation
techniques to protect structures against damage from earthquake attacks has been considered as one of the most effective
approaches and has gained increasing acceptance during the last two decades. This paper present three dimensional nonlinear
time history analysis is performed on r/c building by the use of computer program SAP 2000 v12.0.0. The dynamic analysis of the
structure has been carried out and the performance of the building with and without isolator is studied. The main objective here is
to make seismic response control by providing Isolators and comparing between the fixed based and isolated base building.
Rubber bearing and Friction pendulum bearing are used
Keywords: Base Isolation; Seismic Response; Time History
SEISMIC PROTECTION OF RC FRAMES USING FRICTION DAMPERSIAEME Publication
The increasing infrastructural growth incurs large investments and large section of society
being served by them, it is necessary to make them safer against earthquakes and let people
feel confident in their structures. The need for structural response control has gained pace in
application around the globe. This paper discusses the use and effectiveness of one such
device, friction dampers, for response control of structures. In this paper a non-linear time
history analysis has been carried out on a 3D model of a 12 story RCC MRF building using 3-
directional synthetic accelerogram. Two different cases of building models with and without
friction dampers have been analyzed using ETABS. The response of the structure to seismic
excitation in terms of absolute maximum displacement and story drift has been compared.
Time history response plots have also been compared for various responses viz. roof
displacement and acceleration, base shear and story shear forces, along with the various
energy components and damping behavior. The results of the time history analysis are in close
conformation with previous investigations and represent the effectiveness of dampers in
improving the structural response as well as damping demand on structural systems.
SEISMIC RESPONSE OF UNSYMMETRIC BUILDING WITH OPTIMALLY PLACED FRICTION DAMPERSIAEME Publication
Conventional methods of seismic rehabilitation with concrete shear walls or steel bracing
are not considered suitable for some buildings as upgrades with these methods would have
required expensive and time consuming foundation work. Supplemental damping in
conjunction with appropriate stiffness offers an innovative and attractive solution for the
seismic rehabilitation of such structures. This paper deals with the use of friction damper as a
passive dissipative device in order to seismic retrofit of existing structures and discusses the
optimal placement criteria. To fulfill this objective, six storey and ten storey L-shaped
buildings have been modeled with five different damper location formats in SAP2000 subjected
to El Centro and Utterkashi earthquake records. Non-Linear Modal Time History Method has
been used for the analysis and base shear, joint displacement, member forces and hysteresis
energy has been compared to find out most optimal damper location format.
Seismic Performance of Reinforced Cement Concrete Structures with and Without...ijtsrd
Passive energy dissipation have been used so far to dissipate the unwanted energy due to earthquake and heavy wind actions. The complete failure of the structures that has occurred in the past due to catastrophic earthquakes may be avoided with the use of such devices. The study is concerned with the use of accordion metallic dampers that uses hysteretic energy to dissipate the unwanted energy due to earthquake. It consists of corrugated thin wall tubes installed as a brace connection in the frame. The axial deformation of the accordion damper enhances the lateral buckling capacity and results in maximum reduction of the damaging measures. The study emphasizes the use of such dampers and in depth analysis is performed by subjecting the building to base excitations in order to assess the nonlinear performance of the dampers installed in the building Rahul Tahilyani | Dilip Budhlani ""Seismic Performance of Reinforced Cement Concrete Structures with and Without Viscous Dampers"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30122.pdf
Paper Url : https://www.ijtsrd.com/engineering/civil-engineering/30122/seismic-performance-of-reinforced-cement-concrete-structures-with-and-without-viscous-dampers/rahul-tahilyani
Comparison of bracings and shear walls as seismic strengthening methods to bu...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Analysis of rc framed structures with central and partial openings in masonry...eSAT Journals
Abstract In Reinforced concrete frames the masonry infill walls are a common practice in countries like India, where the region is prone to seismic activity. In general, the masonry infill walls are treated as nonstructural element in structural analysis and only the contribution of its mass for is considered and it’s structural parameters like strength and stiffness is generally ignored in practice, such an approach may lead to an unsafe design. Infill walls resist lateral loads but because of the openings in the infill wall the resistance may slightly reduce. The IS code provisions do not provide guidelines for the analysis and design of RC frames with infill wall and for different percentage of openings. In this study, an office or residential building outer side central opening or outer side partial openings are used and analysis is carried for Bare Frame model, infill walls without opening, infill walls with outer periphery central opening and infill wall with outer periphery partial opening models. In ETABS software G+14 RC framed building models has been prepared, Equivalent Static Lateral force method, Response spectrum method has been performed for analysis as per IS 1893 : 2002 including p-delta effects. Storey displacement, Storey shear, Storey drift, with soft storey considering the effects of infill wall with central and partial openings are the parameters considered in this study. For modeling, the Equivalent diagonal strut method has been used to find out the width of Strut using FEMA 273 .The results for bare frame, infill wall, and infill wall with central and partial openings are discussed and conclusions are made. Keywords: Equivalent diagonal strut, stiffness, Drift limitation
A parametric study of x and v bracing industrial steel structureeSAT Journals
Abstract Severe earthquakes have an extremely low probability of occurrence during a structures life. If the earthquakes to be resisted by the structure elastically, it would require an expensive lateral load resisting system, which is not warranty. The structure may lose its aesthetic and functionality due to minor tremors and needs repairs; it will be a very unfavourable design. In addition to earthquake forces there may be wind or any vibrations which induce lateral loads in a structure. In our work we have taken only the earthquake load to find a system which balances the lateral loads and minimizes the displacements of the floors. With the literature review, it was founded that bracing in a structural system reduces the story drift and reduces the lateral force effect. To examine the performance of the bracings, bracing types like X and V bracings are considered and an analysis is performed in ETABS software. The results are studied, discussed and concluded for the best bracing system among both in our project. Keywords: Bracings, Time – History method
Comparison of Two Similar Buildings with and without Base IsolationIJARIIT
Reinforced concrete is a major construction material for civil infrastructure in current society.
Construction design has always preceded the development of structural design methodology. Dramatic collapse of
buildings has been observed after each disastrous earthquake, resulting in loss of life. To prevent such a loss Baseisolation
is used which enables a building to survive potentially devastating seismic impact by providing flexibility into
the connection between the building and the foundation. The mechanism of the base isolator increases the natural
period of the overall structure, and decreases its acceleration response to earthquake/seismic motion. A reinforced
concrete building with lead rubber bearing is used. The study analysis performed to check for the adequacy of the
base isolation against earthquake damage when compared to the conventional earthquake resistant design. A building
was analyzed using the equivalent lateral force method and response spectrum analysis as fixed base (FB) and as
isolated base (IB) with lead rubber bearing. The analysis represents a case study for reinforced concrete to show the
ultimate capacity of the selected bearing system, and to make a comparison for the difference between the isolated
base and the fixed base buildings. R esults show that the presence of the lead rubber bearing reduces significantly the
displacement, moment and shear generated for the same mode and hence the reinforcement required is also lesser
when compared to the traditional fixed based structure.
Eatrhquake response of reinforced cocrete multi storey building with base iso...eSAT Journals
Abstract A seismic base isolation is an earthquake resistant design method that is based on reducing the seismic demand and also the ductility demand. The basic concept of base isolation system is to increase the natural time period of the fixed base building and to protect the structure from the seismic effect. The main purpose of this work is to study the dynamic response of structure when subjected to different isolators. For this purpose, a three dimensional response spectrum analysis and time history analysis is performed using a commercial structural analysis software package called as SAP 2000 to study the influence of isolation damping on building. The main objective is to make a comparison between the fixed base building and various isolation systems such as friction pendulum isolator, lead rubber bearing (LRB) isolator and high damping rubber isolator, subjected to strong earthquakes to achieve an optimal design of the base isolation system. SAP 2000, a popular large scale explicit finite element analysis software used to stimulate the behavior of base isolated structure. In the present work, it was found that base isolation substantially increases the time period of structure and hence correspondingly reduces the base shear. The top displacement for fixed and isolated cases conspicuously shows the reduction in the case of isolated frame. The study shows that the bending moment and shear force values are reduced for base isolated frame when compared to fixed base building. From design consideration the steel requirement is reduced in base isolated structures when compared to fixed base building. Key Words: Isolators, SAP2000
ELASTOMERIC BASE ISOLATION SYSTEM FOR SEISMIC MITIGATION OF LOW-RISE STRUCTURESIAEME Publication
Seismic base isolation is a passive way of achieving seismic response control by introducing isolators between foundation and super structure. Isolator performs three functions: horizontal flexibility, energy dissipation and rigidity against normal lateral loads. Lead Rubber bearing isolators
performs these functions efficiently. By reducing the horizontal stiffness of the system, it increases the time period of the structure and decreases the spectral acceleration of the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. Such type of isolators are used
in practice in India, yet a proper design procedure based on IS code is unavailable. The paper presents design procedure for LRB adopting the procedure of IS 1893:2002 (Part-1) for earthquake resistant design of buildings.
DESIGN OF BOX CULVERT AS PER IRC-112: 2011, INTERNSHIP PROJECT REPORT.
INCLUDES:
1) BASIC DETAILS
2) DESIGN OF 2 CELL BOX CULVERT
3) DESIGN OF WING WALLS (RETAINING WALLS) AS PER IRC
Base isolation is one of the most widely accepted seismic protection systems in earthquake prone areas. It mitigates the effect of an earthquake by essentially isolating the structure from potentially dangerous ground motions, especially in frequency range where building is mostly affected. This includes
Concept of Base Isolation
Principle of Base Isolation
Comparison of Fixed Base Structure and Isolated Base Structure
Types of Isolation Components
Base Isolation in Real Buildings
Applications of Base Isolation
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Experimental studies on confined steel concrete composite beams under pure be...eSAT Journals
Abstract
An experimental investigation of the ultimate strength and behaviour of a new type of composite beam called CSCC beam (Confined Steel Concrete Composite Beam) is a concrete beam shuttered with cold formed steel sheet which acts as a composite beam by means of shear connectors and bracings. Stud shear connectors are used to take up the bond between sheet and concrete. The passive confinement by the cold formed sheet in the sides and bottom influences the strength and ductility of the system. These beams are provides very good confinement of concrete. Totally eight CSCC beams are tested and the entire behaviour of the beams are monitored to predict the physical response of the beams under three different types loading such as pure bending, pure torsion and combined bending and torsion. Two point loading was obtained for pure bending. The deformation criteria (deflection, moment and flexural rigidity) are also included in the investigation throughout the entire load history experimentally. The results obtained by the experimental values which are found to be in good agreement.
Keywords—composite beams; pure bending
Free vibrational analysis of curved beam with uniform rectangular cross sectioneSAT Journals
Abstract
Curved beams are plays an important role in different field like house roofing, bridges, cranes, automobiles chasses etc. The study
deals with the investigation of free vibrations of thick curved beams of SS316 and MS1018, both experimentally and using ANSYS.
The curved beams having different R/t ratio were fabricated by using mild steel material. Three different boundary conditions are
imposed for curved beams are as follows; free-free, clamped-free, clamped-clamped. For experimental investigation, magnetic
transducer and VIBXpert are used to conduct experiment on different curved beams. The present work also aims at developing a
numerical model for comparing ANSYS results with experimental results to analyze the frequencies and mode shapes
corresponding to three different boundary conditions. The curved beam were modelled, meshed and analyzed using ANSYS. The
first ten natural frequencies from finite element solutions are then compared with the experimental results. These effects also
become more significant for higher modes. It is also observed that the finite element solutions are closely in agreement with
experimental results.
Key words: Curved beams, Experimental investigation, Natural frequencies, modes
Analysis and design of high rise building frame using staad proeSAT Journals
Abstract The Aim of present study “Analysis and design of high rise building by staad pro 2008” is to define proper technique for creating Geometry, cross sections for column and beam etc, developing specification and supports conditions, types of Loads and load combinations. In this study a 30- storey high rise structure is analyzed for seismic and wind load combination using staad pro 2008 and comparison is drawn. Keywords: Analysis, Geometry, Structure, Wind load
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Seismic performance of a rc frame with soft storey criteriaeSAT Journals
Abstract
Soft first storey is a typical feature in the modern multi-storey constructions in urban India. Social and functional need to provide parking space at ground level leads seismic vulnerability of such a building. The computer software usage in civil engineering has greatly reduced the complexities of different aspects in the analysis and design of projects. In the present study an attempt has been made to investigate the seismic behaviour of a multi-storey building with soft first storey. When subjected to seismic loads, it was observed that soft storey frames are less resistant when compared to infill frames.
Keywords: Masonry Infill (MI), Soft storey, relative stiffness, Diagonal strut, Base shear, response spectrum analysis, Time history analysis.
Seismic vulnerability of flat plate column joint with out slab shear reinforc...eSAT Journals
Abstract During an earthquake, a brittle punching failure can arise in flat plate-column connections due to poor transfer capacity of shearing forces and unbalanced moments. To increase the shear capacity of the slab, various types of shear reinforcement can be used in the slab around the connection. The aim of the project is to study the response of slab column connections containing without slab shear reinforcement when subjected to combined gravity and cyclic lateral loading. At first a calibration model was developed to simulate the tested flat plate-column joint using finite element analysis program MASA. This model was used to predict the load displacement behaviour. The predicted behaviour was compared with the observed behaviour as reported by James Lee & Ian Robertson (Ref.4). The comparison showed that the model predicts the load level excellently but significantly over estimates the stiffness of the joint compared to that observed by James Lee & Ian Robertson. Since the present study is to compare the relative behaviour of slab-column joints provided without slab shear reinforcement, the error in the estimation of joint stiffness will not alter the comparative conclusions drawn. Thus, the developed model was validated for application to various types of column slab connection behaviour. Keywords: Flat plate, slab column joint, punching shear, Drift and cyclic lateral loading
Parametric study on slender column for flat plate structureeSAT Journals
Abstract This paper deals with effect of slender column on flat plate structure. The column is called slender if the height of is increased for functional purpose. The study is conducted on 18 flat-plate reinforced cement concrete (RCC) structural models. Among these18 models, 54 columns at three different locations (i.e. corner, edge and inner columns) are chosen for study. The models are developed using ETABS Software. Parametric study is performed by considering six different height of column ranging from 3048 mm to 6858 mm, using an increment of 762 mm along with three slab panels of size 4572 mm x 4572 mm, 6096 mm x6096 mm and 7620 mm x 7620 mm with five panels in both ways, considering both gravity and environmental load. The effect of slenderness ratio on load carrying capacity, design load and steel ratio is considered along with this the effect of additional moment due to slender compression member is also taken into account. It is observed that, columns in flat-plate structures are generally very sensitive if they are slender. It is observed that as the column length increases from 5502 mm and further, the steel ratio suddenly increases and it exceeds maximum allowed. As slenderness ratio increases, ratio of design load to the critical buckling load increases. Also resulting in increase of additional moment, decreasing load carrying capacity of column. This forces the design engineer to study effect of different parameter of the structure while designing high rise flat plate structure. Keywords: Flat Plate Structure, ETABS, Slenderness, Environmental load, design load and buckling load.
Loading, unloading and reloading on square footing with geogrid as a reinforc...eSAT Journals
Abstract Superstructure transmits its loads to the foundation, and then to ground. Loading, unloading and reloading is happens in petroleum tanks and ship repair tracks. This paper presents laboratory tests were carried out on square footing having dimensions of 0.1 X 0.1m for different densities of 16.10kN/m3 , 16.89kN/m3 , 17.29kN/m3 .Coated yarn geogrid is used as reinforcing material. In the present. Paper investigations were carried on by varying number of reinforcement layers such as N = 0, 1 2, 3.Drawn conclusion is as density of foundation bed increases, settlement of the footing decreases and as number of layers of reinforcement increases, settlement of the footing reduces. Keywords: Geogrid, square footing, LVDT, loading, unloading, reloading
Effect of base isolation in multistoried rc irregular building using time his...eSAT Journals
Abstract Base isolation (BI) is a technique that has been used around the world to protect the building structures from the damaging effects of earthquake. The installation of isolator in building at base level significantly increases the time period of the structure, which means it reduces the possibility of resonance of the structure giving rise to better seismic performance of the building. The study is performed to compare the effectiveness of base isolation in plan irregular and vertical irregular multi-storied RC frame building. For this study, 15 storied R.C frame building is considered and Time History analysis is carried out using ETABS 2013 software. The Lead Rubber Bearing (LRB) is designed as per UBC 97 code and the same was used for analysis of base isolation system. The results obtained from the analysis were time period and base shear. Time period for the base isolated structures are higher than that of the fixed base structure. Due to the presence of isolator, Base shear is significantly reduced in each direction (X and Y direction) as compared to fixed base building. It has been found that when compared to plan irregular base isolated building the vertical irregular building gives better performance in high seismic prone area by using isolators at the base of the building.
Keywords: Base isolation, Lead rubber bearing, Time history analysis, Irregular building
Seismic comparative study on tmd structure an overvieweSAT Journals
Abstract In larger context of civil engineering use of mechanical vibration control device is very often in present days, so this paper will provide the successful implementation specification of TMD to reduce the vibration induced due earthquake ground motion, with computer stimulated model & dynamic responses are obtained for seismic loading with & without TMD which drastically reduces seismic response such as lateral displacement, story drift, base shear, overturning moment. Even actual behavior study on structure has been carried by inducing ground motion to the structure by considering time history data of El-Centro & recent earthquake (2014) which happened in India. Keywords: TMD, Time History, Base Shear, Story Drift, El-Centro etc…
Earthquake analysis on 2 d rc frames with different aspect ratios of masonry ...eSAT Journals
Abstract
RC structures are one of the most famous and most utilized types of construction throughout the world. The wall panels for this type of
structures usually are made of masonry infill or monolithic RC panels. In this paper, earthquake analysis of a typical 2D-RC frame is
carried out. Masonry infill is modeled as equivalent diagonal strut and monolithic panel is modeled as shell element. Modal analysis
is carried out on the models and the results are compared with the shake table tests conducted at Central Power Research Institute
(CPRI), Bangalore to validate the models. Earthquake analysis is continued with equivalent static, response spectrum and time history
analyses for all the zones (II-V) as per IS: 1893(Part-1):2002. The analysis results such as natural frequency, displacement, interstorey
drift and acceleration are tabulated, compared and conclusions are drawn.
Key words: 2D-RC Frame, Masonry Infill, Monolithic wall, Shake table, Natural Frequency, Modal analysis, Response
spectrum, Equivalent Diagonal Strut, Time History, Inter-Storey drift.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Earthquake analysis on 2 d rc frames with different aspect ratios of masonry ...eSAT Journals
Abstract
RC structures are one of the most famous and most utilized types of construction throughout the world. The wall panels for this type of
structures usually are made of masonry infill or monolithic RC panels. In this paper, earthquake analysis of a typical 2D-RC frame is
carried out. Masonry infill is modeled as equivalent diagonal strut and monolithic panel is modeled as shell element. Modal analysis
is carried out on the models and the results are compared with the shake table tests conducted at Central Power Research Institute
(CPRI), Bangalore to validate the models. Earthquake analysis is continued with equivalent static, response spectrum and time history
analyses for all the zones (II-V) as per IS: 1893(Part-1):2002. The analysis results such as natural frequency, displacement, interstorey
drift and acceleration are tabulated, compared and conclusions are drawn.
Key words: 2D-RC Frame, Masonry Infill, Monolithic wall, Shake table, Natural Frequency, Modal analysis, Response
spectrum, Equivalent Diagonal Strut, Time History, Inter-Storey drift.
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Seismic performance assessment of the torsional effect in asymmetric structur...eSAT Journals
Abstract In the recent time we come across many structures which are irregular in shape, this type of cannot be avoided due to the functional and architectural requirements. These type of structures have irregular distribution of centre of mass and centre of rigidity which causes the torsional effect on the structures which is one of the most important factor influencing the seismic damage of the structure. Structures with asymmetric distribution of mass and rigidity undergoes torsional motions during earthquake. To assess the torsional effect on the structures in the present study four types of structures are considered with varying eccentricity subjected to Pushover Analysis and Non-Linear Time History Analysis. The performance of the structures are assessed as per the procedure prescribe in ATC-40 and FEMA-356. The analysis of the structural models is done in ETABS. The results have shown that the structures with less eccentricity and in the direction of the columns orientation are performing well, also ductility, drift, and lateral displacement depends on the eccentricity of the structures. Key Words: Symmetric Structure, Asymmetric Structure, Pushover Analysis, Non-Linear Time History Analysis.
Optimisation of earth quake response of tall building by using different fram...eSAT Journals
Abstract In India reinforced concrete structures are mostly used since this is the most convenient & economic system for low-rise buildings. However, for medium to high-rise buildings this type of structure is no longer economic because of increased dead load, less stiffness, span restriction and hazardous formwork. So the Structural engineers are facing the challenge of striving for the most efficient and economical design solution. Also Earthquake engineering should be extended to the design of earthquake sensitive tall buildings. Use of composite material is of particular interest, due to its significant potential in improving the overall performance through rather modest changes in manufacturing and constructional technologies. In India, many consulting engineers are reluctant to accept the use of composite steel-concrete structure because of its unfamiliarity and complexity in its analysis and design. But literature says that if properly configured, then composite steel-concrete system can provide extremely economical structural systems with high durability, rapid erection and superior seismic performance characteristics. This paper discusses Optimization of Earth quack response of tall building by using different types of framing system over the height of the building . So to optimize the earth quack response, a Ten story Combined model ( R.C.C, Composite and Steel frames) is developed and analyzed by using ETABS ; it proves that the combined model is better option. Key Words: Composite structure, Tall Building and Steel structures
Case study on slender multi storey rc building with brick infilleSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Finite element analysis of frame with soil structure interactioneSAT Journals
Abstract
For the analysis of a building frame, the columns at the foundation level are considered as fixed. But in real condition it is not the case. While considering soil in the analysis of building frame 100% fixity may not be ensured. Because of the settlement and rotation of foundation, shear force and bending moment in superstructure get altered. This effect is called as “Soil Structure Interaction” Present work is to study behavior of bare frame & in-filled frame having soil beneath. In these cases three types of soils are considered, soft, medium stiff and hard. Also in-filled panel is of brick masonry only. Various cases frames are studied. The following are the cases:
1] Analysis of bare frame with soil.2] Analysis of In-filled frame with Soil.3] Analysis of Bare frame without Soil.4] Analysis of In-filled frame without Soil Frame with different combinations mentioned above (with/without infill panel, with/without soil) is analyzed by using ANSYS 14.5. These results are comprised with SSI and without SSI.
Keywords: Soil Structure Interaction, In-Filled Frame, Bare Frame.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Similar to Study on laminated rubber bearing base isolators for seismic protection of structures (20)
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
Abstract
Soil stabilization has proven to be one of the oldest techniques to improve the soil properties. Literature review conducted revealed
that uses of natural inorganic stabilizers are found to be one of the best options for soil stabilization. In this regard an attempt has
been made to evaluate the influence of RBI-81 stabilizer on properties of black cotton soil through laboratory investigations. Black
cotton soil with varying percentages of RBI-81 viz., 0, 0.5, 1, 1.5, 2, and 2.5 percent were studied for moisture density relationships
and strength behaviour of soils. Also the effect of curing period was evaluated as literature review clearly emphasized the strength
gain of soils stabilized with RBI-81 over a period of time. The results obtained shows that the unconfined compressive strength of
specimens treated with RBI-81 increased approximately by 250% for a curing period of 28 days as compared to virgin soil. Further
the CBR value improved approximately by 400%. The studies indicated an increasing trend for soil strength behaviour with
increasing percentage of RBI-81 suggesting its potential applications in soil stabilization.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
Abstract
Increase in traffic along with heavier magnitude of wheel loads cause rapid deterioration in pavements. There is a need to improve
density, strength of soil subgrade and other pavement layers. In this study an attempt is made to improve the properties of locally
available loamy soil using twin approaches viz., i) increasing the compaction of soil and ii) treating the soil with chemical stabilizer.
Laboratory studies are carried out on both untreated and treated soil samples compacted by different compaction efforts. Studies
show that increase in compaction effort results in increase in density of soil. However in soil treated with chemical stabilizer, rate of
increase in density is not significant. The soil treated with chemical stabilizer exhibits improvement in both strength and performance
properties.
Keywords: compaction, density, subgradestabilization, resilient modulus
Geographical information system (gis) for water resources managementeSAT Journals
Abstract
Water resources projects are inherited with overlapping and at times conflicting objectives. These projects are often of varied sizes
ranging from major projects with command areas of millions of hectares to very small projects implemented at the local level. Thus,
in all these projects there is seldom proper coordination which is essential for ensuring collective sustainability.
Integrated watershed development and management is the accepted answer but in turn requires a comprehensive framework that can
enable planning process involving all the stakeholders at different levels and scales is compulsory. Such a unified hydrological
framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
The present paper describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) which is
intended to meet the specific information needs of the various line departments of a typical State connected with water related aspects.
The HIS consist of a hydrologic information database coupled with tools for collating primary and secondary data and tools for
analyzing and visualizing the data and information. The HIS also incorporates hydrological model base for indirect assessment of
various entities of water balance in space and time. The framework would be maintained and updated to reflect fully the most
accurate ground truth data and the infrastructure requirements for planning and management.
Keywords: Hydrological Information System (HIS); WebGIS; Data Model; Web Mapping Services
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
Abstract
Efficiency of the road network system is analyzed by travel time reliability measures. The study overlooks on an important measure of
travel time reliability and prioritizing Tiruchirappalli road network. Traffic volume and travel time were collected using license plate
matching method. Travel time measures were estimated from average travel time and 95th travel time. Effect of non-motorized vehicle
on efficiency of road system was evaluated. Relation between buffer time index and traffic volume was created. Travel time model has
been developed and travel time measure was validated. Then service quality of road sections in network were graded based on
travel time reliability measures.
Keywords: Buffer Time Index (BTI); Average Travel Time (ATT); Travel Time Reliability (TTR); Buffer Time (BT).
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
Abstract
Land and water are the two vital natural resources, the optimal management of these resources with minimum adverse environmental
impact are essential not only for sustainable development but also for human survival. Satellite remote sensing with geographic
information system has a pragmatic approach to map and generate spatial input layers of predicting response behavior and yield of
watershed. Hence, in the present study an attempt has been made to understand the hydrological process of the catchment at the
watershed level by drawing the inferences from moprhometric analysis and runoff. The study area chosen for the present study is
Yagachi catchment situated in Chickamaglur and Hassan district lies geographically at a longitude 75⁰52’08.77”E and
13⁰10’50.77”N latitude. It covers an area of 559.493 Sq.km. Morphometric analysis is carried out to estimate morphometric
parameters at Micro-watershed to understand the hydrological response of the catchment at the Micro-watershed level. Daily runoff
is estimated using USDA SCS curve number model for a period of 10 years from 2001 to 2010. The rainfall runoff relationship of the
study shows there is a positive correlation.
Keywords: morphometric analysis, runoff, remote sensing and GIS, SCS - method
-
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
Effect of skew angle on static behaviour of reinforced concrete slab bridge d...eSAT Journals
Abstract
The effect of a skew angle on single-span reinforced concrete bridges is analyzed using the finite-element method and the results are
presented in this paper. Investigations are carried out on RC slab bridge decks with and without edge beams to study the influence of
aspect ratio, skew angle and type of load. The finite-element analysis results for skewed bridges are compared to the reference
straight bridges for dead load, IRC Class A loading and IRC 70R loading for with and without edge beam. A total of 90 bridge models
are analyzed. The variation of maximum deflection, maximum longitudinal sagging bending moment, maximum torsional moment, and
maximum support reaction with skew angle is studied for all 90 bridge deck models. The FEA results of Dead load and Live load
bending moments and deflections decreases with increase in skew angle, where as maximum support reactions increases with increase
in skew angle and the maximum torsional moment increases with skew angle up to 45 degrees and there after decreases. The benefit
of providing edge beam is reflected in significant decrease in deflection, longitudinal bending moment and torsional moment.
Keywords: Bridges, skew angle; Concrete slabs; Finite element method; span length; dead load; IRC Class A loading
and IRC Class 70R loading.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Study on laminated rubber bearing base isolators for seismic protection of structures
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 466
STUDY ON LAMINATED RUBBER BEARING BASE ISOLATORS FOR
SEISMIC PROTECTION OF STRUCTURES
Ganga Warrier A1
, Balamonica K2
, Sathish Kumar K3
, Dhanalakshmi4
1
M.Tech Structural Engineering Student, Department of Civil Engineering, Manipal Institute of Technology,
Karnataka, India
2
Senior Project Fellow, CSIR-Structural Engineering Research Centre, Council of Scientific and Industrial Research,
Chennai, India
3
Senior Principal Scientist, CSIR-Structural Engineering Research Centre, Council of Scientific and Industrial
Research, Chennai, India
4
Assistant Professor, Department of Civil Engineering, Manipal Institute of Technology, Karnataka, India
Abstract
Base isolation or seismic base isolation is an effective means for protection of structures, its contents and its occupants during the
event of an earthquake. The principle of base isolation is vibration isolation. It decouples the building from damaging action of
the earthquake. The isolator partially reflects and partially absorbs input seismic energy before it gets transmitted to the
superstructure. Laminated Rubber Bearing Isolators are placed between the superstructure and foundation, which reduces the
horizontal stiffness of the system. It thereby increases the time period of the structure and decreases the spectral acceleration of
the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. Such type of isolators are used in
practice in India, yet a proper design procedure based on IS code is unavailable. The paper presents design procedure for LRB
adopting the procedure of IS 1893:2002 (Part-1) for earthquake resistant design of buildings. Design charts have been developed
and presented in this paper which gives isolator diameter and rubber thickness as design outputs. The design procedure requires
different input parameters like fundamental period and damping of the fixed base structure, axial load on the column, seismic
zone, type of soil and shore hardness of rubber. These design charts enable the designer to easily arrive at the isolator parameters
to achieve seismic isolation. Using the charts, case study has been done using SAP2000. Building displacement and acceleration
are compared for model with and without base isolator. Comparative study of linear and non-linear base isolators has also been
carried out. Linear and non-linear time history analysis has been done using El Centro earthquake.
Keywords: base isolation, laminated rubber bearing, IS Code, seismic protection, design charts, time history analysis,
SAP2000
--------------------------------------------------------------------***----------------------------------------------------------------------
1. INTRODUCTION
Earthquake is one of the major natural disasters which cause
damages to the buildings. Due to its damaging power, it is
not only important to have strong structures, but also
seismically protected structures. Base isolation is a simple
and practically feasible method of seismic protection of
structures.
1.1 Base Isolation
There are two major types of base isolation, namely,
elastomeric and sliding. Both systems are designed to take
the weight of the building and let the foundations move
sideways during an earthquake. This paper deals with the
laminated rubber bearing isolator, which falls under the first
category. A layer of rubber with much lower horizontal
stiffness is introduced between superstructure and the
foundation. After the isolation, the system has a natural
period much longer than the fixed base natural period. A
typical low damping natural rubber bearing isolator is
shown in Figure 1[1].
When the period is increased, pseudo-acceleration is
decreased and hence the force in the structure gets reduced
(Figure 2[2]). However, the displacement of the system
increases drastically. This is due to the deformation of the
rubber layer.
LRB isolators have cylindrical rubber bearings, which are
reinforced with steel shims. Shims and rubber is placed as
alternate layers. Steel plates are also provided at the two
ends of the isolator. The steel shims boost the load carrying
capacity, thus the structure is stiff under vertical loads and
flexible under horizontal loads.
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 467
Fig -1: Low damping natural rubber bearing[1]
Fig -2: Elastic design spectrum [2]
1.2 Linear Theory of Base Isolation
This can be explained based on two-mass structural model
as shown in Figure 3[1]. The mass m represents the
superstructure of the building and mb mass of the base floor
above the isolation system. The other parameters are
structural stiffness (Ks) and damping (Cs) and base isolator
stiffness (Kb) and damping (Cb). The absolute displacements
of the masses are given by Us and Ub and the ground
displacement is given by Ug. Therefore, the relative
displacements are given by
-
The basic equations of motion of the two-degree-of-freedom
system are
- [1]
This can be written in matrix form as
+ + =
üg [2]
Where
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 468
+Kv=-Mrüg
a ratio γ i i en y
[3]
The natural frequencie ωb and ωs are given by
ω ω
The da pin factor βb and βs are given by
ω β ω β
In terms of these quantities, the basic equation of motion
becomes
γ ω β ω
ω β ω - [4]
Fig -3: Parameters of two degree of freedom isolation
system [1]
2. DEVELOPMENT OF EQUATIONS
2.1 To Find the Thickness of Isolator
Fig -4: Behaviour of isolator under shear
Shear train of the i olator, γ i i en y (Fi ure 4),
γ
t
Where Len th of defor ation
t=thickness of the isolator
γ i a u ed to e 100% in thi analysis.
Therefore,
is the spectral displacement of the structure as per IS
1893-2002 Part I. We assume that the isolator gets deformed
keeping the structure intact. Hence the maximum
displacement of isolator is
i.e,
But, Sd
Sa
ω
Therefore t ω
Where,
Sa= Spectral acceleration of the isolator
ω frequency of the tructure
By considering the zone factor (Z), importance factor (I) and
response reduction factor (R), the above equation can be
written as
t
h
ω
Where, the horizontal acceleration coefficient,
for DBE, h
Sa
for MCE h
Sa
2.2 To Find Diameter of Isolator:
The linear frequency of the isolator is given by,
f
1
Where k= Stiffness of the isolator
m= Mass of the isolator
f
ω
ω Natural frequency of the i olator
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 469
Horizontal stiffness of the isolator,
Load
eflection
Load Shear tre ro ectional area
From eq (11),
[12]
Substituting the value of stiffness in Eq.(10), we get
ω
t
ω t
W
Using Eq(5) the above equation can be modified as,
W
Also
Sd
Sa
ω
Substituting Eq(15) in Eq(14),
Therefore,
W (
Sa
)
Incorporating the Importance factor, Response reduction
factor and Zone factor, the above equation can be modified
as
4Wf 1
Where
1
2= for DBE
Z for MCE
3= 1.0 for hard soil
1.36 for medium soil
1.67 for soft soil
2.3 Layering of Isolator
To keep the ratio of the horizontal and vertical stiffness
equal for the different isolator sets, a parameter called Shape
factor, S is introduced, which is a dimensionless measure of
the aspect ratio of the single layer of the elastomer. For a
single pad in the form of a complete circle, the compression
modulus EC is given by
[19]
Also,
Considering Eq (12) and Eq(20), the following relation can
be obtained.
c
From Eq(10),
ω
ω
Or, it can be further modified as
Therefore Eq(19) can be re-written as,
S
f
f
It is assumed that
Therefore,
Loaded area
Force free area
For circular isolator,
ro ection area
ur ed urface area
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 470
Therefore,
t
4S
The above equation shows that by varying the number of
sandwich layer, quite a large variation in vertical stiffness of
the individual isolator element could be achieved.
3. DESIGN CHARTS
After the equations were developed, a set of charts were
prepared for easy designing of circular laminated rubber
bearing isolator (LBR). The charts were prepared according
to IS 1893 (Part 1): 2002. Charts were prepared for all the
four seismic zones, namely, low (zone II), moderate (zone
III), severe (zone IV) and very severe (zone V). The three
types of soil sites, namely, rocky or hard soil site (Type I),
medium soil site (Type II) and soft soil site (Type III) are
also considered. Charts for different damping ratios like 0,
2, 5, 7, 10, 15, 20, 25, and 30 are prepared. Importance
factor (I) and Response reduction factor (R) is taken as 1 for
all the charts to enable the designer to choose their criteria.
Diameter for circular rubber isolators having shear modulus
value 0.35MPa, 0.7MPa, 1.05MPa, 1.40MPa is developed.
Chart 1 is a typical chart to find the thickness of rubber for
zone V and three soil conditions for Design basis earthquake
for 5% damping. Chart 2 is to find the diameter of isolator
for building with desired time period 2 seconds for Design
basis earthquake for zone V and for soft soil condition for
axial load varying from 50kN to 10000kN.
Chart – 1: Chart for DBE for 5% damping in Zone V
Chart -2:.Chart for DBE for T=2s Soft soil condition(Zone V)
6. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 471
3.1 Interpretation of Charts
3.1.1. To get the Thickness
To get the thickness of the isolator, the desired time period
of the structure after isolation should be assumed.
Corresponding value of thickness can be obtained from the
graph (Chart 1) according to the soil condition, damping and
type of the earthquake considered. According to the type of
structure and importance of structure, Response reduction
factor (R) and Importance factor (I) can be incorporated to
get the final thickness of rubber in the isolator. Further
calculations can be done for obtaining the layering.
3.1.2. To get the Diameter
The diameter of the isolator can be obtained by knowing the
axial load coming on the column and the shear modulus of
the rubber used. From the corresponding charts (Chart 2) for
particular design time period and soil condition, the value of
diameter can be taken. Further calculations considering the
Response reduction factor (R) and Importance factor (I)
should be done to get the final diameter of the isolator.
4. CASE STUDY
4.1Description of the Structure Analyzed
The structure analysed is a two bay three storied reinforced
concrete framed structure consisting of three frames (Frame-
1 to Frame-3). The centre to centre distance between the
columns is 3000mm and the height of each storey is
3600mm. The column section is of 300mm X 400mm size
consisting of two 16mm bars at top and bottom. The beam
section is also of 300mm X 400mm size consisting of two
12mm bars on either side.
Fig -5: Elevation and plan view of the frame
Column has 8mm diameter ties spaced at 150mm centres
and beam has 8mm diameter two legged stirrups at 100mm
centres. The slab is 150mm thick with 12mm bars at 200mm
centres with reinforcement for support moment provided
separately. Figure 5 shows the elevation and typical plan
view of the frame tested for verification of time history
analysis methodology.
4.2 Design of Base Isolator
Models were created in SAP 2000 without base isolator
(Figure 6), with linear base isolator and with non-linear base
isolator. Dead load analysis was done for the self weight of
the system and axial load acting on each column was
obtained (Table 1). The structure was assumed to be in Zone
V, built on soft soil. The rubber used for the isolator is
assumed to have a shear modulus of 0.35MPa.
Fig -6: SAP 2000 model of the frame
Table1. Axial load on column and dimensions of base
isolator
Column
Number
Axial
Load
(kN)
Thickness
of Rubber
(mm)
Diameter
of
Isolator
(mm)
Thickness
of Layer
(mm)
1 81.45 150 220 5.5
2 122.8 150 280 7
3 81.45 150 220 5.5
4 127.1 150 280 7
5 195.1 150 420 11
6 127.1 150 280 7
7 81.45 150 220 5.5
8 122.8 150 280 7
9 81.45 150 220 5.5
Columns 1, 3, 7 and 9 have same axial load. Also, columns
2, 4, 6 and 8 have similar loads. Therefore, 3 isolators were
designed for the whole structure.
7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 472
Fig -7: Detail design of isolator for central column
The detail design of isolator below the central column is given in Figure 7.
4.3 Linear Time History Analysis
Initially a gravity load analysis and modal analysis is carried out the system. Linear time history analysis of the frame is carried
out using SAP-2000 software. El Centro earthquake (Figure 8) is used in the time history analysis. Figure 9 shows the SAP-2000
model of the frame with base isolator.
Fig -8: North-South component of El Centro earthquake, May 18, 1940
8. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 473
Fig -9: SAP model of the frame with base isolator
Acceleration on the building and displacement of the building, before and after installation of base isolator is compared. Graphs
are plotted for the same (Chart 3 and 4).
Chart -3: Comparison of acceleration of building with and without base isolator
9. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 474
Chart -4: Comparison of displacement of building with and without base isolator.
4.4 Non-Linear Time History Analysis
The non-linear behavior of isolator is simplified as bilinear [3]. The po t yieldin tiffne ratio (α) are a u ed to e 0.05, 0.1
and 0.15 for the isolator. The yield strength of non-linear case (F1) is taken as one-tenth, one-fifth, one-third, half and three-fourth
of yield strength of linear case (F1, elastic). Fifteen cases are considered in total. Bilinear hysteresis loops were obtained. A typical
bilinear hysteresis loop for for α 0.05 and F1=0.1F1,elastic is shown in Chart 5.
Chart -5:Bilinear hy tere i loop for α 0.05 and F1=0.1F1,elastic
10. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 475
From the hysteresis loop, the additional damping and the effective stiffness values are calculated. The values are given in Table 2.
Table -2: Additional damping and effective stiffness of non-linear isolator
Cases Additional Damping ζe (%) Effective Stiffness Ke (kN/m)
α 0.05, F1=0.10F1,elastic 22.12 25.5
α 0.10, F1=0.10F1,elastic 17.53 38.9
α 0.15, F1=0.10F1,elastic 11.86 53.1
α 0.05, F1=0.20F1,elastic 25.04 23.3
α 0.10, F1=0.20F1,elastic 15.85 36.4
α 0.15, F1=0.20F1,elastic 17.19 52.2
α 0.05, F1=0.33F1,elastic 19.48 20.5
α 0.10, F1=0.33F1,elastic 15.91 35.5
α 0.15, F1=0.33F1,elastic 13.97 51.1
α 0.05, F1=0.50F1,elastic 12.98 18.7
α 0.10, F1=0.50F1,elastic 9.83 34.4
α 0.15, F1=0.50F1,elastic 8.01 50.3
α 0.05, F1=0.75F1,elastic 6.60 17.8
α 0.10, F1=0.75F1,elastic 5.67 33.8
α 0.15, F1=0.75F1,elastic 5.82 49.9
4.5 Comparison of Linear and Non-Linear Analysis
Displacement of building with linear and non-linear base isolators is compared. Displacement is seemed to be reduced when
isolators are designed as non-linear. The comparison is given in table 3.
Table -3: Displacement reduction in non-linear analysis
Cases Displacement (m) Reduction (%)
α 0.05, F1=0.10F1,elastic 0.0789 32.61
α 0.10, F1=0.10F1,elastic 0.0853 27.13
α 0.15, F1=0.10F1,elastic 0.0947 19.10
α 0.05, F1=0.20F1,elastic 0.0885 24.40
α 0.10, F1=0.20F1,elastic 0.0783 33.09
α 0.15, F1=0.20F1,elastic 0.0806 31.12
α 0.05, F1=0.33F1,elastic 0.0915 21.84
α 0.10, F1=0.33F1,elastic 0.0852 27.15
α 0.15, F1=0.33F1,elastic 0.0850 27.33
α 0.05, F1=0.50F1,elastic 0.0927 20.81
α 0.10, F1=0.50F1,elastic 0.0930 20.52
α 0.15, F1=0.50F1,elastic 0.0926 20.86
α 0.05, F1=0.75F1,elastic 0.0963 17.70
α 0.10, F1=0.75F1,elastic 0.0954 18.44
α 0.15, F1=0.75F1,elastic 0.0946 19.11
5. RESULTS
For the same soil condition and time period, thickness
of the isolator decreases with increase in damping
percentage.
Buildings situated on soft soil conditions require
thicker isolator than those situated on hard soil
conditions, provided the required time period and
damping are the same.
For a particular value of axial load which is to be
transferred, the diameter of the isolator increases, as
isolator with rubber of lesser value of shear modulus
is used.
The diameter of isolator decreases as the desired
value of time period increases, provided the soil
condition and the rubber used are the same.
Buildings situated on soft soils need isolator with
bigger diameter than situated on hard rocky soils.
Both thickness and diameter increases as greater
earthquake prone area is chosen.
11. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 02 | Feb-2015, Available @ http://www.ijret.org 476
Linear time history analysis shows that acceleration on the
building decreases after the installation of base isolator,
whereas the building displacement increases after the
installation. The maximum value of acceleration on the
building before the introduction of base isolator is 10.96m/s2
and after the installation is 1.12m/s2
. The value of building
displacement is 40.68mm before installing isolator and
117.7mm after the installation.
Results of non-linear analysis shows that a maximum
additional damping of 25.04% was obtained for post
yielding stiffness ratio of 0.05 and non-linear yield strength
taken as one-fifth of linear yield strength.
On comparing linear and non-linear isolators, a maximum
displacement reduction of 33.09% in the case of post
yielding stiffness ratio of 0.10 and non-linear yield strength
taken as one-fifth of linear yield strength was obtained,
when the isolators are designed as non-linear.
6. CONCLUSION
The guidelines for designing laminated rubber bearing
(LRB) isolators are developed. Design charts for arriving at
the details of base isolators are prepared. Different isolator
parameters were compared with respect to fundamental
period and damping of the fixed base structure, axial load on
the column, seismic zone, type of soil and shore hardness of
rubber.
Acceleration on building and displacement are altered by the
installation of isolator. Acceleration on the building
decreases and displacement of the building increases. This
increase in displacement can be reduced if the isolator is
designed as non-linear. Additional damping is also
introduced by the non-linear isolator.
ACKNOWLEDGEMENTS
The paper is published with the kind permission of Director,
CSIR-SERC, Chennai, Tamil Nadu, India.
REFERENCES
[1]. Farzad Naeim and James. M. Kelly, Design of seismic
isolated structures: From Theory to practice, John Wiley &
Sons, 1999
[2]. Anil. K. Chopra, Dynamics of structures: Theory and
practice to Earthquake engineering, Prentice Hall, 1995
[3]. Andriono, T and Carr, A. J (1991), “ i plified
earthquake resistant design method for base isolated multi
toried tructure ”, Bulletin of the New ealand National
Society for Earthquake Engineering. Vol 24, No 3 pp238-
250
[4]. Indian Standard Criteria for earthquake resistant design
of structures Part 1: General provisions and buildings (Fifth
revision), IS 1893:Part1(2002)
BIOGRAPHIES
Ganga Warrier A is a Civil Engineering
graduate from LBS College of
Engineering, Kasaragod and is currently
pursuing her Masters in Structural
Engineering at Manipal Institute of
Technology, Manipal. She is doing her
project in CSIR-SERC, Chennai. Her
research areas include seismic response control and seismic
base isolation.
K. Balamonica is a Research Scholar in
the Academy of Scientific and Innovative
Research (AcSIR) and currently Senior
Project Fellow in the Advanced Seismic
Testing and Research Laboratory of
CSIR-SERC, Chennai. Her research areas
of interest are Structural dynamics, Earthquake Engineering
and Structural Health Monitoring
Dr. K. Sathish Kumar is currently Senior
Principal Scientist in the Advanced
Seismic Testing and Research
Laboratory of CSIR-SERC, Chennai. He
is also a Professor in the Academy of
Scientific and Innovative Research
(AcSIR). His research areas of interest
include Seismic Response Control and Pseudo-dynamics.
Dhanalakshmi is an Assistant Professor
in Manipal Institute of Technology
(MIT), Manipal. She earned Masters
from MIT, Manipal and B.E degree from
Dr. Ambedkar Institute of Technology,
Bangalore. Her fields of interest are
structural engineering and concrete technology.