Abstract Buckling is a critical state of stress and deformation, at which a slight disturbance causes a gross additional deformation, or perhaps a total structural failure of the part. Structural behavior of the part beyond 'buckling' is not evident from the normal arguments of static. Buckling failures do not depend on the strength of the material, but are a function of the component dimensions & modulus of elasticity. Therefore, materials with a high strength will buckle just as quickly as low strength ones. If a structure is subject to compressive loads, then a buckling analysis may be necessary. The study presented in this paper is intended to help designers of steel braced barrel vaults by identifying the significant differences in determining which configuration(s) would be best in different conditions of use. The study presented is of parametric type and covers several other important parameters like rise to span ratio, different boundary conditions, such that barrel vault acts as an arch, as a beam or as a shell, The buckling strength of a three different configuration of a double layer braced barrel vaults are presented in this paper for rise/span ratio varying from 0.2-0.7 and having four different types of boundary conditions. Through consideration of these parameters, the paper presents an assessment of the effect of the vault configuration on the overall buckling strength. Keywords: Buckling, Steel Barrel Vault, Single Layer
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 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.
Buckling Analysis and Stability of Compressed Low-Carbon Steel Rods in the El...► Victor Yepes
This paper presents new approaches for solving a problem of the stability of compressed rods in the elastoplastic working region of materials. It is known that the columns of buildings, supports of engineering devices, drill rods of oil, and gas extraction industry may be subjected to significant risk of stability loss. Nowadays, there are design methods based on test results defining the relations (e.g., critical stresses-slenderness) to avoid this risk due to stability loss, but the precision and limits of definition are not always known. The main objectives of the study were to develop new approaches that would allow specifying the values of critical stresses of compressed elements beyond the proportional limit. The problem of stability of the compressed elements in the elastoplastic region was studied according to the stability theory. The authors suggested an original approach to the issue; in particular, the determination of values of the critical stresses and the finding of the points of the bifurcation were carried out by the tangent established by experimental results and by the approximation of the so-called double modulus. Comparative analysis showed the advantage of the proposed approach, particularly that the new critical curves were located below the curves of Engesser-Karman and Shanley and above the critical curves established by building codes. A new approach for the determination of critical stresses in the elastoplastic region was developed through which the structural reliability and economic efficiency was increased by almost 12% compared to the existing approaches.
Effect of concentric and eccentric type of bracings on performance based seis...eSAT Journals
Abstract When a tall building is subjected to lateral or torsional deflections under the action of seismicloads, the resulting oscillatory movement can induce a wide range of responses in the building’s occupants.[1]As a result, lateral stiffness is a major consideration in the design of tall buildings. Bracing is a highly efficient and economical method of resisting lateral forces in a frame structure. In this present study, the effect of four different types of bracing systems have been studied, for the use in SMRF RC framed building situated in seismic zone IV, in order to provide lateral stiffness and results in terms of storey shears and storey drifts have been presented. Keywords: RC Building, Concentric and Eccentric Bracings, Storey Drift,Storey Shear, Pushover Curves.
Evaluation of the use of concentric steel bracing to improve seismic performa...eSAT Journals
Abstract Most of the existing RC frame structures were not designed to withstand seismic effect. To meet those criteria structures should be retrofitted and out of all available retrofitting techniques adding steel braces are considered to be most efficient technique to enhance the seismic performance of the RC frame structure. In the present study three types of buildings are considered i.e., (G+2), (G+5), (G+8) as low rise, medium rise, high rise respectively, and these buildings are assigned by four different types of braces namely X, V, Inverted V, Eccen Forward at the periphery bays of the building in three different pattern i.e., model A, model B and model C. And these buildings are analyzed by nonlinear pushover analysis by using SAP2000.It is observed that the hinges were first formed in beams and followed by columns in bare frame whereas hinges were first formed in braces and followed by columns and followed by beams in case of X, Eccen forward brace and in case of V and inverted V hinges are formed first in brace followed by beams and followed by columns. It is pointed out that RC frames which are assigned with inverted V brace has least shear force and bending moment in the beams when compared to the other brace frames and there is less amount of variations in axial force shear force and bending moment in case of column. Keywords: equivalent static analysis, steel braces, equivalent strut method
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
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 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.
Buckling Analysis and Stability of Compressed Low-Carbon Steel Rods in the El...► Victor Yepes
This paper presents new approaches for solving a problem of the stability of compressed rods in the elastoplastic working region of materials. It is known that the columns of buildings, supports of engineering devices, drill rods of oil, and gas extraction industry may be subjected to significant risk of stability loss. Nowadays, there are design methods based on test results defining the relations (e.g., critical stresses-slenderness) to avoid this risk due to stability loss, but the precision and limits of definition are not always known. The main objectives of the study were to develop new approaches that would allow specifying the values of critical stresses of compressed elements beyond the proportional limit. The problem of stability of the compressed elements in the elastoplastic region was studied according to the stability theory. The authors suggested an original approach to the issue; in particular, the determination of values of the critical stresses and the finding of the points of the bifurcation were carried out by the tangent established by experimental results and by the approximation of the so-called double modulus. Comparative analysis showed the advantage of the proposed approach, particularly that the new critical curves were located below the curves of Engesser-Karman and Shanley and above the critical curves established by building codes. A new approach for the determination of critical stresses in the elastoplastic region was developed through which the structural reliability and economic efficiency was increased by almost 12% compared to the existing approaches.
Effect of concentric and eccentric type of bracings on performance based seis...eSAT Journals
Abstract When a tall building is subjected to lateral or torsional deflections under the action of seismicloads, the resulting oscillatory movement can induce a wide range of responses in the building’s occupants.[1]As a result, lateral stiffness is a major consideration in the design of tall buildings. Bracing is a highly efficient and economical method of resisting lateral forces in a frame structure. In this present study, the effect of four different types of bracing systems have been studied, for the use in SMRF RC framed building situated in seismic zone IV, in order to provide lateral stiffness and results in terms of storey shears and storey drifts have been presented. Keywords: RC Building, Concentric and Eccentric Bracings, Storey Drift,Storey Shear, Pushover Curves.
Evaluation of the use of concentric steel bracing to improve seismic performa...eSAT Journals
Abstract Most of the existing RC frame structures were not designed to withstand seismic effect. To meet those criteria structures should be retrofitted and out of all available retrofitting techniques adding steel braces are considered to be most efficient technique to enhance the seismic performance of the RC frame structure. In the present study three types of buildings are considered i.e., (G+2), (G+5), (G+8) as low rise, medium rise, high rise respectively, and these buildings are assigned by four different types of braces namely X, V, Inverted V, Eccen Forward at the periphery bays of the building in three different pattern i.e., model A, model B and model C. And these buildings are analyzed by nonlinear pushover analysis by using SAP2000.It is observed that the hinges were first formed in beams and followed by columns in bare frame whereas hinges were first formed in braces and followed by columns and followed by beams in case of X, Eccen forward brace and in case of V and inverted V hinges are formed first in brace followed by beams and followed by columns. It is pointed out that RC frames which are assigned with inverted V brace has least shear force and bending moment in the beams when compared to the other brace frames and there is less amount of variations in axial force shear force and bending moment in case of column. Keywords: equivalent static analysis, steel braces, equivalent strut method
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
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
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
Strengthening of RC Framed Structure Using Energy Dissipation DevicesIOSR Journals
A large numbers of existing buildings in India are severely deficient against earthquake forces and
the number of such buildings is growing very rapidly. This paper presents a way of using energy dissipation
devices for seismic strengthening of a RC framed structure. The objective was to improve the seismic
performance of the building to resist the earthquake. The viscous dampers are used as an energy dissipation
device in the form of single, double, inverted V, V type of dampers with different percentages of damping such
as 10%, 20% and 30% to prevent building from collapse in a major earthquake and also to control the damage
during earthquake. The performance of the buildings is assessed as per the procedure prescribed in ATC-40
and FEMA 356.
Design of short sstt confined circular hsc columnseSAT Journals
Abstract Steel-straps tensioning technique (SSTT) has been proven to be an effective mean to confined High-strength concrete (HSC). The pre-tensioned force offers by this confining method can significantly restraint the small lateral dilation of HSC. However, most of the design guidelines only concerned with FRP-confined columns subjected to concentric compression. The direct application of these design guidelines on the SSTT-confined HSC column is being questioned due to different material and confining method adopted. Hence, a numerical study was carried out in the view of developing a simple design equation for HSC column confined with SSTT. The parameters such as SSTT-confinement ratio, load eccentricities and slenderness ratio were tested. Based on the numerical results, design equations based on regression analysis were proposed to determine the ultimate load and bending moment of SSTT-confined HSC columns. Index Terms:Confinement, Steel Straps, Eccentric loads, and Theoretical Model.
Analytical assessment on progressive collapse potential of new reinforced con...eSAT Journals
Abstract Progressive collapse is a catastrophic partial or total failure that mostly occurs when a structure looses a primary structural component or more like a column or any vertical load resisting component due to natural or manmade hazard. In this research paper a new undergoing construction of Reinforced concrete 12 storied building located in Whitefield, Bangalore is modelled in accordance with the actual drawings according to Indian standard codes and analysed for progressive collapse potential by using structural design and analysis software Etabs2013. For evaluating the effect of progressive collapse in accordance with the guidance of U.S General Service Administration (GSA) linear static method is followed. The analytical model is checked for Demand capacity ratio by removing primary vertical support, one column at a time and evaluating whether the member is resistance to progressive collapse. Many such columns are removed and analysed to know the behaviour of building on abnormal loading conditions. The result shows that progressive collapse can be resisted by providing proper detailing and adequate reinforcement to the beams and columns. Keywords: Progressive collapse, Demand Capacity Ratio (DCR), General Service Administration standards (GSA), Design software Etabs2013, linear static
Fragility analysis of open ground storey rc building designed using various m...eSAT Journals
Abstract The vulnerability of an element is defined as the probability that the said element will sustain a specified degree of structural damage given a certain level of ground motion severity. Significantly low stiffness and strength in any storeys compared to adjacent storeys is generally referred to as soft ground storey. As the columns of this Open ground storey are weakest element, ground storey is most vulnerable. Open ground storey framed buildings are generally analyzed in practice ignoring infill wall stiffness (linear bare frame analysis). Design codes impose a multiplication factor on the design forces in the columns of ground storey. The present study attempts to estimate and compare performance of open ground storey building designed with three different multiplication factors given by Indian code and Israel code. Thus fragility curves are derived using nonlinear dynamic time history analysis carried on a (G+9) OGS building by using method suggested by Cornell. Probabilistic seismic demand models are developed by using power law model. Results show that performance of upper storeys while applying multiplication factor only to the ground storey needs to be checked. The first storey is more vulnerable than the ground storey except for Israel code. Keywords: Open ground storey, multiplication factors, fragility, performance levels, PSDM Model
International Journal of Engineering and Science Invention (IJESI) inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
seismic response of multi storey building equipped with steel bracingINFOGAIN PUBLICATION
Steel bracing has proven to be one of the most effective systems in resisting lateral loads. Although its use to upgrade the lateral load capacity of existing Reinforced Concrete (RC) frames has been the subject of numerous studies, guidelines for its use in newly constructed RC frames still need to be developed. In this paper the study reveals that seismic performance of moment resisting RC frames with different patterns of bracing system. The three different types of bracings were used i.e. X - bracing system, V - bracing system and Inverted V - bracing system. This arrangement helped in reducing the structural response (i.e. displacement, interstorey drift, Shear Forces & Bending Moments) of the designed building structure. An (G+6) storey building was modelled and designed as per the code provisions of IS-1893:2002. And linear analysis is been carried out in the global X direction. The analysis was conducted with a view of accessing the seismic elastic performance of the building structure.
Comparison of symmetric and asymmetric steel diagrid structures by non linear...eSAT Journals
Abstract Diagonalized grid structures – “diagrids” - have emerged as one of the most innovative and adaptable approaches to structuring buildings in this millennium. Diagrid is a particular form of space truss, it consists of perimeter grid made up of a series of triangulated truss system. Diagrid is formed by intersecting the diagonal and horizontal components. Construction of multi‐storey building is rapidly increasing throughout the world. Advance in construction technology, materials, structural systems, various analysis and design software have facilitated the growth of various kinds of buildings. Diagrid buildings are emerging as structurally efficient as well as architecturally and aesthetically significant assemblies for tall buildings. Recently these diagrid structural systems have been widely used for tall buildings due to the structural efficiency and aesthetic potential provided by the unique geometric configuration of the system. This paper presents a 12 storey steel diagrid structure which is 36m in height. Symmetric and asymmetric structural configurations of diagrid structures were modelled and analyzed using SAP 2000 by considering Dead load, Live load and Seismic Loads (IS 1893-Part-1, 2002). Then FEMA 356 hinges (auto hinges) are assigned to the same structure and Nonlinear Static (Pushover) analysis is carried out by using seismic load as the pushover load case to find out the performance points that is Immediate Occupancy, Life Safety, and Collapse Prevention of diagrid elements using static pushover curve. At the same time spectral displacement demand & spectral displacement capacity as well as spectral acceleration demand and spectral acceleration capacity is compared to know the adequacy of the design by using ATC capacity spectrum method. Keywords: Diagrid, Pushover analysis, Spectral displacement demand, Spectral displacement capacity, Spectral acceleration demand, Spectral acceleration capacity
PROGRESSIVE COLLAPSE ANALYSIS OF REINFORCED CONCRETE SYMMETRICAL AND UNSYMMET...AM Publications
Progressive collapse is a chain reaction of failures that propagates either throughout or a portion of the
structure disproportionate to the original local failure. The progressive collapse of building structure is initiated when
one or more vertical load carrying members are removed. Once a column is removed or made weak, due to man-made or
natural hazards, load carried by column removed is transferred to neighboring columns in the structure, if the
neighboring column is incapable of withstanding the extra load, leads to the progressive failure of adjoining members and
finally to the failure of partial or whole structure. The collapsing system continually seeks alternative load paths in order
to survive. One of the important characteristics of progressive collapse is that the final damage is not proportional to
the initial damage. The research material available for progressive collapse failure of structures suggests that
buildings designed to resist seismic actions have good robustness against progressive collapse. However, no detailed
investigations have been conducted so far to assess this robustness. Hence this study is made to examine the potential
ability of seismically designed building against progressive collapse. A Five storey reinforced concrete framed
structure symmetrical and Unsymmetrical was considered in the study to evaluate the Demand Capacity Ratio
(D.C.R.), the ratio of the member force and the member strength as per U.S. General Services Administration (GSA)
guidelines. The Linear static analysis is carried out using software, ETABS V 9.7 according to Indian Standard codes.
Analysis and design is carried out to get the final output of design details. To study the collapse, typical columns are
removed one at a time, and continued with analysis and design. Many such columns are removed in different trials to
know the effects of progressive analysis. Member forces and reinforcement details are calculated. From the analysis,
DCR values of beams are calculated.
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
Analysis of s s short cylindrical shells under internal hydrostatic pressure ...eSAT Journals
Abstract A new approach to the analysis of S-S short cylindrical shells subject to internal hydrostatic pressure is presented. Short cylindrical shells with both ends simply supported (S-S) loaded with axisymmetric internal hydrostatic pressure was considered. By satisfying the boundary conditions of S-S short cylindrical shell in the general polynomial series shape function, a particular shape function for the shell was obtained. This shape function was substituted into the total potential energy functional of conservation of work principle, and by minimizing the functional; the unknown coefficient of the particular polynomial shape function was obtained. Bending moments, shear forces and deflections of the shell were determined, and used in plotting graphs for a range of aspect ratios, 1 ≤ L/r ≤ 4. Stresses and deflections at various points of the shell were determined for different cases. Considering case one, with aspect ratio 1, maximum values of deflection, rotation, bending moment and shear force were m, -3.29878radians,KNm and KN respectively. Thus we observed that the stresses and strains along the S-S short cylindrical reservoir vary inversely as the aspect ratio. Key Words: Analysis, Boundary condition, Conservation of work principle, Hydrostatic pressure, Polynomial series, Shape function, Short cylindrical shell.
Optimization of a multistorey building by optimum positioning of shear walleSAT Journals
Abstract The shear wall is a structural element which is used to resist earthquake forces. These wall will consumptives shear forces & will prevent changing location-position of construction & consequently destruction. On other hand, shear wall arrangement must be absolutely accurate, if not, we will find negative effect instead. For example if the shear walls make an increase distance between mass centre and hardness centre, we cannot expect a good tensional behavior from the structure. In case of mass centre and hardness centre coincide with each other, at that time the distance of shear wall from the mass centre also plays an important role in the shear contribution of the shear wall. The bending moment, shear force, torsion, axial force contribution by rest of the structural element and the ultimate design of all the structural components also affected by that. A study has been carried out to determine the optimum Structural configuration of a multistory building by changing the shear wall locations radically. Four different cases of shear wall position for a 10 storey residential building with keeping zero eccentricity between mass centre and hardness centre have been analyzed and designed as a space frame system by computer application software, subjected to lateral and gravity loading in accordance with IS provisions. Keywords: Shear walls, Lateral loading, Zero eccentricity, Stresses, Design configuration.
Effect of modulus of masonry on initial lateral stiffness of infilled frames ...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.
A study of r.c.c. beam column connection subjected to monotonic loadingeSAT Journals
Abstract
Beam and column where intersects is called as joint or Connection. The different types of joints are classified as corner joint, exterior
joint, interior joint etc. on beam column joint applying quasi-static loading .i. e. monotonic loading on cantilever end of the beam and
study of various parameters as to be find out on corner and exterior beam column joint i.e. maximum stress, minimum stress,
displacement and variation in stiffness of beam column joint can be analyzed in Ansys software ( Non-Linear FEM Software) The
various research studies focused on corner and exterior beam column joints and their behavior, support conditions of beam-column
joints. Some recent experimental studies, however, addressed beam-column joints of substandard RC frames with weak columns, poor
anchorage of longitudinal beam bars and insufficient transverse reinforcement. the behavior of exterior beam column joint is different
than the corner beam column joint.
Keywords: beam, column, corner, exterior, joint, monotonic load, quasi-static, varying stiffness
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
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
Strengthening of RC Framed Structure Using Energy Dissipation DevicesIOSR Journals
A large numbers of existing buildings in India are severely deficient against earthquake forces and
the number of such buildings is growing very rapidly. This paper presents a way of using energy dissipation
devices for seismic strengthening of a RC framed structure. The objective was to improve the seismic
performance of the building to resist the earthquake. The viscous dampers are used as an energy dissipation
device in the form of single, double, inverted V, V type of dampers with different percentages of damping such
as 10%, 20% and 30% to prevent building from collapse in a major earthquake and also to control the damage
during earthquake. The performance of the buildings is assessed as per the procedure prescribed in ATC-40
and FEMA 356.
Design of short sstt confined circular hsc columnseSAT Journals
Abstract Steel-straps tensioning technique (SSTT) has been proven to be an effective mean to confined High-strength concrete (HSC). The pre-tensioned force offers by this confining method can significantly restraint the small lateral dilation of HSC. However, most of the design guidelines only concerned with FRP-confined columns subjected to concentric compression. The direct application of these design guidelines on the SSTT-confined HSC column is being questioned due to different material and confining method adopted. Hence, a numerical study was carried out in the view of developing a simple design equation for HSC column confined with SSTT. The parameters such as SSTT-confinement ratio, load eccentricities and slenderness ratio were tested. Based on the numerical results, design equations based on regression analysis were proposed to determine the ultimate load and bending moment of SSTT-confined HSC columns. Index Terms:Confinement, Steel Straps, Eccentric loads, and Theoretical Model.
Analytical assessment on progressive collapse potential of new reinforced con...eSAT Journals
Abstract Progressive collapse is a catastrophic partial or total failure that mostly occurs when a structure looses a primary structural component or more like a column or any vertical load resisting component due to natural or manmade hazard. In this research paper a new undergoing construction of Reinforced concrete 12 storied building located in Whitefield, Bangalore is modelled in accordance with the actual drawings according to Indian standard codes and analysed for progressive collapse potential by using structural design and analysis software Etabs2013. For evaluating the effect of progressive collapse in accordance with the guidance of U.S General Service Administration (GSA) linear static method is followed. The analytical model is checked for Demand capacity ratio by removing primary vertical support, one column at a time and evaluating whether the member is resistance to progressive collapse. Many such columns are removed and analysed to know the behaviour of building on abnormal loading conditions. The result shows that progressive collapse can be resisted by providing proper detailing and adequate reinforcement to the beams and columns. Keywords: Progressive collapse, Demand Capacity Ratio (DCR), General Service Administration standards (GSA), Design software Etabs2013, linear static
Fragility analysis of open ground storey rc building designed using various m...eSAT Journals
Abstract The vulnerability of an element is defined as the probability that the said element will sustain a specified degree of structural damage given a certain level of ground motion severity. Significantly low stiffness and strength in any storeys compared to adjacent storeys is generally referred to as soft ground storey. As the columns of this Open ground storey are weakest element, ground storey is most vulnerable. Open ground storey framed buildings are generally analyzed in practice ignoring infill wall stiffness (linear bare frame analysis). Design codes impose a multiplication factor on the design forces in the columns of ground storey. The present study attempts to estimate and compare performance of open ground storey building designed with three different multiplication factors given by Indian code and Israel code. Thus fragility curves are derived using nonlinear dynamic time history analysis carried on a (G+9) OGS building by using method suggested by Cornell. Probabilistic seismic demand models are developed by using power law model. Results show that performance of upper storeys while applying multiplication factor only to the ground storey needs to be checked. The first storey is more vulnerable than the ground storey except for Israel code. Keywords: Open ground storey, multiplication factors, fragility, performance levels, PSDM Model
International Journal of Engineering and Science Invention (IJESI) inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
seismic response of multi storey building equipped with steel bracingINFOGAIN PUBLICATION
Steel bracing has proven to be one of the most effective systems in resisting lateral loads. Although its use to upgrade the lateral load capacity of existing Reinforced Concrete (RC) frames has been the subject of numerous studies, guidelines for its use in newly constructed RC frames still need to be developed. In this paper the study reveals that seismic performance of moment resisting RC frames with different patterns of bracing system. The three different types of bracings were used i.e. X - bracing system, V - bracing system and Inverted V - bracing system. This arrangement helped in reducing the structural response (i.e. displacement, interstorey drift, Shear Forces & Bending Moments) of the designed building structure. An (G+6) storey building was modelled and designed as per the code provisions of IS-1893:2002. And linear analysis is been carried out in the global X direction. The analysis was conducted with a view of accessing the seismic elastic performance of the building structure.
Comparison of symmetric and asymmetric steel diagrid structures by non linear...eSAT Journals
Abstract Diagonalized grid structures – “diagrids” - have emerged as one of the most innovative and adaptable approaches to structuring buildings in this millennium. Diagrid is a particular form of space truss, it consists of perimeter grid made up of a series of triangulated truss system. Diagrid is formed by intersecting the diagonal and horizontal components. Construction of multi‐storey building is rapidly increasing throughout the world. Advance in construction technology, materials, structural systems, various analysis and design software have facilitated the growth of various kinds of buildings. Diagrid buildings are emerging as structurally efficient as well as architecturally and aesthetically significant assemblies for tall buildings. Recently these diagrid structural systems have been widely used for tall buildings due to the structural efficiency and aesthetic potential provided by the unique geometric configuration of the system. This paper presents a 12 storey steel diagrid structure which is 36m in height. Symmetric and asymmetric structural configurations of diagrid structures were modelled and analyzed using SAP 2000 by considering Dead load, Live load and Seismic Loads (IS 1893-Part-1, 2002). Then FEMA 356 hinges (auto hinges) are assigned to the same structure and Nonlinear Static (Pushover) analysis is carried out by using seismic load as the pushover load case to find out the performance points that is Immediate Occupancy, Life Safety, and Collapse Prevention of diagrid elements using static pushover curve. At the same time spectral displacement demand & spectral displacement capacity as well as spectral acceleration demand and spectral acceleration capacity is compared to know the adequacy of the design by using ATC capacity spectrum method. Keywords: Diagrid, Pushover analysis, Spectral displacement demand, Spectral displacement capacity, Spectral acceleration demand, Spectral acceleration capacity
PROGRESSIVE COLLAPSE ANALYSIS OF REINFORCED CONCRETE SYMMETRICAL AND UNSYMMET...AM Publications
Progressive collapse is a chain reaction of failures that propagates either throughout or a portion of the
structure disproportionate to the original local failure. The progressive collapse of building structure is initiated when
one or more vertical load carrying members are removed. Once a column is removed or made weak, due to man-made or
natural hazards, load carried by column removed is transferred to neighboring columns in the structure, if the
neighboring column is incapable of withstanding the extra load, leads to the progressive failure of adjoining members and
finally to the failure of partial or whole structure. The collapsing system continually seeks alternative load paths in order
to survive. One of the important characteristics of progressive collapse is that the final damage is not proportional to
the initial damage. The research material available for progressive collapse failure of structures suggests that
buildings designed to resist seismic actions have good robustness against progressive collapse. However, no detailed
investigations have been conducted so far to assess this robustness. Hence this study is made to examine the potential
ability of seismically designed building against progressive collapse. A Five storey reinforced concrete framed
structure symmetrical and Unsymmetrical was considered in the study to evaluate the Demand Capacity Ratio
(D.C.R.), the ratio of the member force and the member strength as per U.S. General Services Administration (GSA)
guidelines. The Linear static analysis is carried out using software, ETABS V 9.7 according to Indian Standard codes.
Analysis and design is carried out to get the final output of design details. To study the collapse, typical columns are
removed one at a time, and continued with analysis and design. Many such columns are removed in different trials to
know the effects of progressive analysis. Member forces and reinforcement details are calculated. From the analysis,
DCR values of beams are calculated.
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
Analysis of s s short cylindrical shells under internal hydrostatic pressure ...eSAT Journals
Abstract A new approach to the analysis of S-S short cylindrical shells subject to internal hydrostatic pressure is presented. Short cylindrical shells with both ends simply supported (S-S) loaded with axisymmetric internal hydrostatic pressure was considered. By satisfying the boundary conditions of S-S short cylindrical shell in the general polynomial series shape function, a particular shape function for the shell was obtained. This shape function was substituted into the total potential energy functional of conservation of work principle, and by minimizing the functional; the unknown coefficient of the particular polynomial shape function was obtained. Bending moments, shear forces and deflections of the shell were determined, and used in plotting graphs for a range of aspect ratios, 1 ≤ L/r ≤ 4. Stresses and deflections at various points of the shell were determined for different cases. Considering case one, with aspect ratio 1, maximum values of deflection, rotation, bending moment and shear force were m, -3.29878radians,KNm and KN respectively. Thus we observed that the stresses and strains along the S-S short cylindrical reservoir vary inversely as the aspect ratio. Key Words: Analysis, Boundary condition, Conservation of work principle, Hydrostatic pressure, Polynomial series, Shape function, Short cylindrical shell.
Optimization of a multistorey building by optimum positioning of shear walleSAT Journals
Abstract The shear wall is a structural element which is used to resist earthquake forces. These wall will consumptives shear forces & will prevent changing location-position of construction & consequently destruction. On other hand, shear wall arrangement must be absolutely accurate, if not, we will find negative effect instead. For example if the shear walls make an increase distance between mass centre and hardness centre, we cannot expect a good tensional behavior from the structure. In case of mass centre and hardness centre coincide with each other, at that time the distance of shear wall from the mass centre also plays an important role in the shear contribution of the shear wall. The bending moment, shear force, torsion, axial force contribution by rest of the structural element and the ultimate design of all the structural components also affected by that. A study has been carried out to determine the optimum Structural configuration of a multistory building by changing the shear wall locations radically. Four different cases of shear wall position for a 10 storey residential building with keeping zero eccentricity between mass centre and hardness centre have been analyzed and designed as a space frame system by computer application software, subjected to lateral and gravity loading in accordance with IS provisions. Keywords: Shear walls, Lateral loading, Zero eccentricity, Stresses, Design configuration.
Effect of modulus of masonry on initial lateral stiffness of infilled frames ...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.
A study of r.c.c. beam column connection subjected to monotonic loadingeSAT Journals
Abstract
Beam and column where intersects is called as joint or Connection. The different types of joints are classified as corner joint, exterior
joint, interior joint etc. on beam column joint applying quasi-static loading .i. e. monotonic loading on cantilever end of the beam and
study of various parameters as to be find out on corner and exterior beam column joint i.e. maximum stress, minimum stress,
displacement and variation in stiffness of beam column joint can be analyzed in Ansys software ( Non-Linear FEM Software) The
various research studies focused on corner and exterior beam column joints and their behavior, support conditions of beam-column
joints. Some recent experimental studies, however, addressed beam-column joints of substandard RC frames with weak columns, poor
anchorage of longitudinal beam bars and insufficient transverse reinforcement. the behavior of exterior beam column joint is different
than the corner beam column joint.
Keywords: beam, column, corner, exterior, joint, monotonic load, quasi-static, varying stiffness
A study of r.c.c. beam column connection subjected to monotonic loadingeSAT Journals
Abstract
Beam and column where intersects is called as joint or Connection. The different types of joints are classified as corner joint, exterior
joint, interior joint etc. on beam column joint applying quasi-static loading .i. e. monotonic loading on cantilever end of the beam and
study of various parameters as to be find out on corner and exterior beam column joint i.e. maximum stress, minimum stress,
displacement and variation in stiffness of beam column joint can be analyzed in Ansys software ( Non-Linear FEM Software) The
various research studies focused on corner and exterior beam column joints and their behavior, support conditions of beam-column
joints. Some recent experimental studies, however, addressed beam-column joints of substandard RC frames with weak columns, poor
anchorage of longitudinal beam bars and insufficient transverse reinforcement. the behavior of exterior beam column joint is different
than the corner beam column joint.
Keywords: beam, column, corner, exterior, joint, monotonic load, quasi-static, varying stiffness.
Non linear static pushover analysis of irregular space frame structure with a...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
Finite element analysis of jacketed reinforced concrete column subjected to u...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 and design of multi storeyed load bearing reinforced masonry struct...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.
Study of Eccentrically Braced Outrigger Frame under Seismic ExitationIJTET Journal
Outrigger braced structures has efficient structural form consist of a central core, comprising braced frames with
horizontal cantilever ”outrigger” trusses or girders connecting the core to the outer column. When the structure is loaded
horizontally, vertical plane rotation of the core is restrained by the outriggers through tension in windward column and
compression in leeward column. The effective structural depth of the building is greatly increased, thus augmenting the lateral
stiffness of the building and reducing the lateral deflections and moments in core. In effect, the outriggers join the columns to the
core to make the structure behave as a partly composite cantilever. By providing eccentrically braced system in outrigger frame by
varying the size of links and analyzing it. Push over analysis is carried out by varying the link size using computer programs, Sap
2007 to understand their seismic performance. The ductile behavior of eccentrically braced frame is highly desirable for structures
subjected to strong ground motion. Maximum stiffness, strength, ductility and energy dissipation capacity are provided by
eccentrically braced frame. Studies were conducted on the use of outrigger frame for the high steel building subjected to
earthquake load. Braces are designed not to buckle, regardless of the severity of lateral loading on the frame. Thus eccentrically
braced frame ensures safety against collapse.
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.
Performance of Flat Slab Structure Using Pushover AnalysisIOSR Journals
Performance Based Seismic Engineering is the modern approach to earthquake resistant design. It
is a limit-state based design approach extended to cover complex range of issues faced by structural engineers.
Flat slabs are becoming popular and gaining importance as they are economical as compared to beam-column
connections in conventional slab. Many existing flat slabs may not have been designed for seismic forces so it is
important to study their response under seismic conditions and to evaluate seismic retrofit schemes. In this
paper we have discussed the results obtained by performing push over analysis on flat slabs by using most
common software SAP2000. A (G+7) frame having 5 bays is considered for analysis. It is observed that the
performance point of flat slab is more as compared to conventional building.
Finite element analysis of jacketed reinforced concrete column subjected to a...eSAT Journals
Abstract One strategy for the jacketing of reinforced concrete column is to target the improvement of local vulnerabilities in columns related to inadequate strength (compressive & Flexural) or poor ductility. Theoretical analysis have been carried out in the present study for different column sections of jacket thickness of 75mm and 100mm for jacketed RC columns subjected to axial and uni-axial compressive loading. The uni-axial load carrying capacity along the major axes has been carried out under balanced section condition. Linear static finite element analysis has been carried out for the jacketed RC columns to compare the confined concrete strength (fcc) of finite element analysis with that of theoretical analysis, to plot the variation of stresses at the central core concrete and at the interface of old and new concrete. The maximum shear stress for the columns is also noted down. The displacement at core with respect to major axis is also plotted. Keywords: Axial load, Uni-axial load, NISA Display IV, Jacketing, confined compressive strength.
Practical analysis procedures of steel portal frames having different connect...Ali Msabawy
The real behaviour of connections in the steel buildings is often underestimated by designers at the structural analysis and design stages, despite their influences on the structural performance, deflection limits and a possibility of achieving a reduction in the material weights, which can significantly reduce the overall cost and amount of energy embodied. This paper, therefore, described systematic and simplified procedures to conduct a first-order elastic structural analysis of the semi-rigid steel portal frames in order to implement a design optimization using a Generalized Reduced Gradient (GRG) algorithm within Solver Add-in tool in Microsoft Excel. The written program used the robustness and efficiency of the Finite Element (FE) method with the versatility of a spreadsheet format in Excel. To simulate the semi-rigid response of the connections, the mathematical representation through End-Fixity Factor and the Modified Stiffness Matrix were used to incorporate such behaviour into structural analysis packages. To validate the written program, a computer-based analysis was conducted using Prokon® software and comparing analysis results with those obtained from the Excel spreadsheet. It demonstrates that Excel's results were perfectly accurate. Consequently, the procedure of establishing spreadsheets as a finite element analysis software for a certain form of frames demonstrates its validity.
The influence of cable sag on the dynamic behaviour of cable stayed suspensio...eSAT Journals
Abstract The demand of long span bridge is increasing with infrastructure magnification. To achieve maximum central span in bridges is a motivating rational challenge. The bridge with more central span can be achieved using high strength materials and innovative forms of the bridges. The cable-stayed bridge has better structural stiffness and suspension bridge has ability to offer longer span thus combination of above two structural systems could achieve very long span cable-stayed suspension hybrid bridge. To distinguish behaviour and check the feasibility of this innovative form of hybrid bridge, 1400m central span and 312m side span cable-stayed suspension hybrid bridge is considered for analysis. The suspension portion length in central span is also playing important role in behaviour of the entire bridge. Bridge behaviour is presented for variable length of suspension portion in form of suspension portion to main span ratio. The main cable sag in central span is playing important role on behavior of the entire bridge. It directly influences the inclination angles of the main cables, the height of pylon and thus forces in pylon. The axial force in main cable is directly depending on the sag of main cable. The effects of main cable sag is studied by considering dimensionless parameter as sag to main span ratio as 1/9, 1/10 and 1/11. Paper also discusses results of nonlinear static analysis and modal analysis carried out using SAP2000 v14.0.0. The time period of bridge is used to present the behavior of bridge. Key Words: Cable supported long span bridge; cable stayed suspension hybrid bridge; cable sag to main span ratio; dynamic analysis
Similar to Performance of single layer steel barrel vault under buckling (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 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.
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.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
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.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
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.
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.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Runway Orientation Based on the Wind Rose Diagram.pptx
Performance of single layer steel barrel vault under buckling
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 02 | Feb-2014, Available @ http://www.ijret.org 558
PERFORMANCE OF SINGLE LAYER STEEL BARREL VAULT
UNDER BUCKLING
Mulesh K. Pathak (M. E. CASAD)
Lecturer in applied mechanic , Department government polytechnic, Valsad- 39600, Gujara, India
Abstract
Buckling is a critical state of stress and deformation, at which a slight disturbance causes a gross additional deformation, or
perhaps a total structural failure of the part. Structural behavior of the part beyond 'buckling' is not evident from the normal
arguments of static. Buckling failures do not depend on the strength of the material, but are a function of the component
dimensions & modulus of elasticity. Therefore, materials with a high strength will buckle just as quickly as low strength ones. If a
structure is subject to compressive loads, then a buckling analysis may be necessary. The study presented in this paper is intended
to help designers of steel braced barrel vaults by identifying the significant differences in determining which configuration(s)
would be best in different conditions of use. The study presented is of parametric type and covers several other important
parameters like rise to span ratio, different boundary conditions, such that barrel vault acts as an arch, as a beam or as a shell,
The buckling strength of a three different configuration of a double layer braced barrel vaults are presented in this paper for
rise/span ratio varying from 0.2-0.7 and having four different types of boundary conditions. Through consideration of these
parameters, the paper presents an assessment of the effect of the vault configuration on the overall buckling strength.
Keywords: Buckling, Steel Barrel Vault, Single Layer
---------------------------------------------------------------------***-------------------------------------------------------------------
1. INTRODUCTION
Barrel vaults are a popular way of spanning large open areas
with few intermediate supports. The past four decades saw an
expanding interest in this form of construction. This is
understandable because these structures can provide a form of
roof construction combining low cost and rapid erection with a
pleasing appearance. Hundreds of successful barrel vault
applications for basement, intermediary and ground floors now
exist all over the world covering public halls, exhibition
centre, aero plane hangers and many other buildings. This
structure is usually used in all types of environment: urban,
rural, plain, mountain or seaside5
.
Barrel vaults have been built with many different
configurations involving different arrangements of
longitudinal, transverse and bracing members including those
sketched in Fig.1. Starting from the basic Configuration-1,
bracing members can be placed in different orientations and
with different intensities up to the most congested
Configuration-4 for double layer barrel vault3
. With every
variation, it is expected that the performance of the vault
would change, leading sometimes to advantageous
improvements in the vault’s strength/weight ratio,
stiffness/weight ratio, failure mode, member stress
distribution, material consumption, degree of redundancy,
aesthetics and cost6
This paper presents the results of a parametric study to identify
the effects of adopting different barrel vault configurations on
the vault’s buckling behavior. The study considers wide
variations of many important parameters including rise/span
ratio, boundary conditions and configurations. The buckling
strength of the vault structure is found out using the STAAD-
PRO software. The data needed for the numerical analyses
was generated using formex configuration processing, which
is based on formex algebra principles2
.
Config.-1 Config.-2
Diagonal on square Square on square
Config.-3 Config. -4
Square on diagonal Diagonal on
diagonal
Fig-1:principal configurations of steel double layer braced
barrel vaults
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 02 | Feb-2014, Available @ http://www.ijret.org 559
2 BUCKLING ANALYSIS
“Buckling” is used as a generic term to describe the strength of
structures, generally under in-plane compressions and/or
shear. It is particularly dangerous because it is a catastrophic
failure that gives no warning. The buckling strength or
capacity can take into account the internal redistribution of
loads depending on the situation.
(A)Buckling capacity with allowance for
redistribution of load
This defines the upper bound value of the buckling capacity
and represents the maximum load the panel can carry without
suffering major permanent set and is effectively the ultimate
load carrying capacity of a panel. The buckling capacity is
taken as the load that results in the first occurrence of
membrane yield stress anywhere in the stiffened panel. The
redistribution of load is a result of elastic buckling of
component plates, such as the plating between the stiffeners.
For slender structures the capacity calculated using this
method is typically higher than the ideal elastic buckling stress
(minimum Eigen-value).
(B)Buckling capacity with no allowance for
redistribution of load
This defines the lower bound value of the buckling capacity.
For slender structures, this is defined as the ideal elastic
buckling stress. This is more conservative than the upper
bound value given by Method 1 and ensures that the panel
does not suffer large elastic deflections with consequent
reduced in-plane stiffness.
Buckling loads are critical loads where certain types of
structures become unstable. Each load has an associated
buckled mode shape; this is the shape that the structure
assumes in a buckled condition. There are two primary means
to perform a buckling analysis:
2.1. Eigenvalue
Eigenvalue (bifurcation) buckling analysis is useful for finding
the load factor and corresponding buckling shape for a given
set of loads and constraints. Eigenvalue buckling analysis
predicts the theoretical buckling strength of an ideal elastic
structure. It computes the structural eigenvalues for the given
system of loading and constraints. This is known as classical
Euler buckling analysis. Buckling loads for several
configurations are readily available from tabulated solutions4
.
However, in real-life, structural imperfections and
nonlinearities prevent most real world structures from reaching
their eigenvalue predicted buckling strength; i.e. it over-
predicts the expected buckling loads.
2.2. Nonlinear
Nonlinear buckling analysis is more accurate than eigenvalue
analysis because it employs non-linear, large-deflection; static
analysis to predict buckling loads. Its mode of operation is
very simple: it gradually increases the applied load until a load
level is found whereby the structure becomes unstable (i.e.
suddenly a very small increase in the load will cause very
large deflections). The true non-linear nature of this analysis
thus permits the modeling of geometric imperfections, load
perturbations, material nonlinearities and gaps. For this type of
analysis, small off-axis loads are necessary to initiate the
desired buckling mode.
The lowest buckling load is of most practical significance, and
is normally achieved when the tangent stiffness associated
with a mode of deformation becomes zero, such a mode then
referred to as the buckling mode. Of course, numerous
sophisticated procedures and computational tools have been
developed over the past few decades that deal with structural
buckling, both in terms of simplified linear eigenvalue analysis
and through tracing the geometrically nonlinear response as
well as material nonlinearity. While the approach proposed in
this paper does not deal with a new class of problem, it sheds
new light on the buckling analysis of skeletal structures,
enabling better understanding of the buckling mechanisms,
and it provides a simplified and practical framework for
buckling predictions, importantly, using linear analysis
principles.
As mentioned above, buckling can be related to the singularity
of the tangent stiffness matrix, which in turn consists of two
parts. The first part is the material stiffness matrix which is
related to the deformational stiffness of the components,
taking into account the connectivity of components in the
current geometric configuration of the structure. For linear
elastic components, the material stiffness is identical to the
linear elastic stiffness, but updating the structural geometry to
include the effect of any displacements.
The second part is the geometric stiffness matrix, which is
related to the component forces, and in some cases to the
applied loading, taking into account the effect of a change in
geometry from the current configuration. For typical
structures, the material stiffness is positive for all deformation
modes, mathematically referred to as positive-definite,
whereas the geometric stiffness can admit negative values for
certain modes, depending on the component forces and applied
loading. It is therefore the effect of a negative geometric
stiffness that can lead to a singular overall tangent stiffness
matrix, and hence buckling.Buckling Equations:
M =0 (1)
M = F u = internal bending moment. Can be replaced with
the corresponding stiffness, [K] {u}
Ku–Fu=0; (2)
[K–F]{u}=0 (3)
In general, this equation is written as:
[K+ Kg]{u}=0(Eigen-problem) (4)
Kg = geometric stiffness matrix, which expresses the
influence of the location of the load on the stiffness of the
structure.
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 02 | Feb-2014, Available @ http://www.ijret.org 560
Where, K and Kg are the stiffness and geometric stiffness
matrices respectively, u is the nodal displacement sector,
which represents the buckling mode shapes, and λ is the load
factor, when multiplying the referenced applied load, gives
the buckling load.
The present study examines the underlying assumptions within
the formulation of the eigenvalue buckling method in order to
highlight the problem types that most readily lend themselves
to solution by this method. In addition, problems presenting
responses that violate these fundamental assumptions are also
examined. If the maximum stress is significantly less than
yield stress, and the buckling load factor (BLF) is greater than
1.0, then buckling will probably not occur. If however the BLF
is less than 1.0, then the buckling analysis will be linear
provided that the maximum stress is far below yield stress.
Convergence Tolerance in STAAD-Pro 2007:
STAAD solves for the eigenvalue-eigenvectors pairs using an
accelerated subspace iteration algorithm. During the solution
phase, the program prints the approximate eigenvalues after
each iteration. As the eigenvectors converge, they are removed
from the subspace and new approximate vectors are
introduced. For details of the algorithm, see Wilson and
Tetsuji (1983).
Each eigenvalue-eigenvector pair is called a natural vibration
mode of the structure. The modes are identified by numbers
from 1 to n in the order in which the modes are found by the
program.
3 PARAMETRIC STUDY
In the present paper, three parameters, which are having
highest influence on the buckling performance of the vault, are
considered. These parameters are as follows:
(1) Vault configuration: The double layer barrel vault of three
most popular configurations, which are used by majority of the
designer, who designs the vault structures, is taken as one
parameter. Diagonal on square (DOS), Square on square
(SOS) and Square on diagonal (SOD) of configurations of
double layer barrel vault are taken in the study. All three types
of configurations are shown in fig.-1.
(2) Rise/span ratio: This is also important parameters for any
arch type of structure. From the literature, it is that, it is varied
from 0.2 to 0.7. This parameter is varied from 0.2 to 0.5 in the
interval of 0.05, and its effect on the buckling performance is
presented in this paper.
(3) Boundary conditions: This is one of the important
parameters for any structure from the stability point of view.
In addition to that, boundary conditions are also effect the
buckling performance of the structures. In the present paper,
boundary conditions are decided in such way that, vault is act
as an arch, a beam or a shell. Thus four different types of
support conditions are considered and is shown in fig.-2
Thus in the present paper, parametric study of the buckling
performance of three different configuration of double layer
barrel vault, with rise/span ratio varied from 0.2 to 0.7 in the
interval of 0.05 and having four different types of support
conditions are presented, which will be useful to the designer
of a barrel vaults.
4 PROBLEM DESCRIPTION
The parametric study is carried out on a problem of barrel
vault, whose plan area is 40 m x 30 m. The vault is having an
arch of 40 m. and length of 30 m. The rise of the vault is taken
as per rise/span ratio, which is one of the parameters in this
study, whose value is varied from 0.2 to 0.7 in the interval of
0.05. The galvanized steel sheet is used as roofing cover
(A) Arch Vault (B) beam vault
(C) corner supp. D) all edges supp. shell vault
shell vault
Fig-2:different boundary conditions considered in buckling
analysis barrel vault
Three different configuration of double layer barrel vault as
mentioned in para 3.0 with four boundary conditions are
considered with the vault acting as an arch (supported along
transverse edge), a beam (supported along longitudinal edge),
a corner supported shell or a shell supported on all edges5
. For
analysis purpose, the vault is divided in 10 transverse panels
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 02 | Feb-2014, Available @ http://www.ijret.org 561
and 8 longitudinal panels. The data needed for the structural
analyses is generated using formian programming language7
,
which is a convenient medium for formex configuration
processing.
4.1 Loads
The following loads are considered:
Dead load: The dead load includes self weight of the structure
and the weight of the roof covering materials. Galvanized
Steel Sheets are used for roofing.
Live load: The live load depends upon rise/span ratio and it is
calculated as per table-2 of IS-875 (Part-II).The dead and live
load are applied as area load.
Wind load: Wind load is the most important of all and it often
controls the design. The Wind load is calculated as per IS:
875–1987(Part-III). ,
As per Indian code,Design For wind Load Vz = Vb*K1*K2*K3
Where Vz is the design wind speed at any height in m/s;
. K1 is risk coefficient=1.06 for this case (table-1 IS: 875 Part-
3); K2 is terrain, height and structure size factor = 0.76 for
cat.4 and class B case (table-2 IS: 875 Part-3);K3 = topography
factor =1 for this case.So, Vz = 31.4184 m/s
Design Wind Pressure Pd = 0.6 Vz
2
= 592.2695 N/m2
Wind force F = (Cpe-Cpi)*A* Pd
Where, Cpe = External pressure coefficient and Cpi = Internal
pressure coefficient. The external pressure coefficient Cpe is
taken considering the case of roof on elevated structure as per
table-15 of IS: 875,Part-III (fig.3).In the table15 of IS-875
values of external pressure coefficients are given at interval of
0.1 of H/l ratio. The Excel sheet is used for calculation of the
intermediate values of Cp by linear interpolation. Internal
pressure coefficient is based on the permeability of structure
and in this problem, it taken as ±0.2. In this case surface
design pressure varies with height, the surface areas of the
structural element may be sub-divided so that the specified
pressures are taken over appropriate areas. Here the total
height of the structure was divided into ten equal parts and
wind force per sq.m area was calculated using Excel sheet.
Positive wind load indicates the force acting towards the
structural element (pressure) and negative away from it
(suction).
Fig-3:wind pressure distribution for roof on elevated structure
as per is: 875(part-3)
Four wind load cases were considered
(a) Wind load parallel to ridge with Cpi= 0.2
(b) Wind load parallel to ridge with Cpi= -0.2
(c) Wind load perpendicular to ridge with Cpi= 0.2
(d) Wind load perpendicular to ridge with Cpi= -0.2
The wind load was applied as concentrated loads on the nodes
of a barrel vault. Determination of wind force on the curved
surface of the barrel vault is complex task and hence in-house
computer program is prepared to calculate wind force at each
node of the structure. The nodal loads are determined by
calculating the area surrounding each node, and multiplying
this area by the total factored load. The Excel sheet is used for
the calculation of nodal load. This process was repeated for
each configuration with a different rise/span ratio and
boundary condition.
Following load cases and load combinations are considered in
the analysis.
(1) Dead load
(2) Live load
(3) Wind load parallel to ridge (Cpi= -0.2)
(4) Wind load parallel to ridge (Cpi= 0.2)
(5) Wind load perpendicular to ridge (Cpi= -0.2)
(6) Wind load perpendicular to ridge (Cpi= 0.2)
(7) Dead load + Live load
(8) Dead load + Wind load parallel to ridge (Cpi= -0.2)
(9) Dead load + Wind load parallel to ridge (Cpi= 0.2)
(10) Dead load + Wind load perpendicular to ridge (Cpi= -
0.2)
(11) Dead load + Wind load perpendicular to ridge (Cpi=
0.2)
(12) Dead load + Live load + Wind load parallel to ridge (Cpi=
-0.2)
(13) Dead load + Live load + Wind load parallel to ridge
(Cpi=0.2)
(14) Dead load + Live load + Wind load perpendicular to ridge
(Cpi=-0.2)
(15) Dead load + Live load + Wind load perpendicular to ridge
(Cpi=0.2)
4.2 Buckling Analysis
Based on the basic loads and load combinations, loads at each
joint of the vault geometry are calculated. The structure is
modeled as space truss and accordingly static analysis is
carried out using software. The preliminary analysis & design
is carried out using professional
software STAAD-Pro. All required
checks of IS: 800-1984 are being taken
care in the design. To get the optimum
sections, the facilities given in the
STAAD-Pro are also exploited.
From an analysis point of view, a
buckling analysis is used to find the
lowest multiplication factor for the
load that will make a structure buckle. The result of such an
analysis is a number of buckling load factors (BLF). The first
BLF (the lowest factor) is always the one of interest. If it is
less than unity, then buckling will occur due to the load being
H/l C C2
0.1 -0.8 -0.8
0.2 -0.9 -0.7
0.3 -1.0 -0.3
0.4 -1.1 +0.4
0.5 -1.2 +0.7
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 02 | Feb-2014, Available @ http://www.ijret.org 562
applied to the structure. The analysis is also used to find the
shape of the buckled structure. Here buckling analysis is done
using STAAD-Pro 2007 and the variation of first B.F. (i.e. in
mode 1) with rise/span ratio is represented in fig.3.
5 CONCLUSION
1 Double Layer Barrel vault configurations that seem to offer
the best overall performance are those that have a regular and
symmetrical arrangement of longitudinal and transverse
members in all the directions in addition to strengthened edges
for example Config.-2 (SOS) offers the best buckling load
capacity approx. more than four times that of Config.-1(DOS),
Config.-3(SOD) and Cofig.-4(DOD)
2 In arch and all edges supported shell boundary conditions
Config.-3(SOD) offers less buckling load capacity than
Config.-1(DOS) but in beam and corner supported shell
boundary conditions it offers more buckling load capacity than
config.-1(DOS).
3 Loss of buckling load capacity with increase in Rise to Span
ratio is least in regular and symmetrical config.-2(SOS).
4 In config.1 (DOS) loss of buckling load capacity with
increase in Rise/Span ratio is more than config.-3(SOD)
except in case of arch boundary condition.
5. Config.-2 (SOS) that have a regular and symmetrical
arrangement of longitudinal and transverse members in all the
directions offers less buckling strength capacity in arch
boundary condition than beam boundary condition , while
config.1 (DOS) and config.-3(SOD) offers more buckling
strength capacity in arch boundary condition than beam
boundary condition.
6. Without internal longitudinal or transverse members, the
buckling behavior of barrel vaults is highly affected especially
when acting in the beam mode or in the shell or arch mode
respectively, i.e. Config. – 4(DOD)
7. In beam boundary condition rate of buckling strength with
increase in Rise/Span ratio is least between all the four
boundary conditions, while in arch boundary condition rate of
buckling strength with increase in Rise/Span ratio is maximum
between all the four boundary conditions.
REFERENCES
[1]Makowski, Z S (1985), “Analysis, Design and Construction
of Braced Barrel Vaults”, Elsevier Applied Science Publishers,
London.
[2]Hoshyar Nooshin and Peter Disney(August 2002),”Formex
Configuration Processing ” , Multi-science Publishing Co.
Ltd.,
[3]Ramaswamy G.S. and M. Eekhout (1999) , ”Analysis,
Design and Construction of Steel Space Frame”, Telford
Publication, U.K.,
[4]N.Subramanian (1999),”Principles of Space Structures”,
Wheeler Publishing, New Delhi.
[5]Ahmed El-Sheikh(2001),” Performance of Single-layer
Barrel Vaults with Different Configurations”, International
Journal of Space Structures Vol.16 No.2
[5]Ahmed El-Sheikh(2002),” Effect of Geometric
Imperfections on Single- Layer Barrel Vaults” International
Journal of Space Structures Vol.17 No.4
[6]Nooshin, H, Disney, P and Yamamoto, C (1993), “Formian:
The Programming Language of Formex Algebra”, University
of Surrey Publication