1. The document discusses a study on the effect of infilled brick walls on the behavior of eccentrically braced frames (EBFs).
2. It describes developing a finite element model to simulate the interaction between the steel frame and masonry wall, and validating the model by comparing results to experimental tests.
3. The validated model is then used to study how the infilled brick wall influences the behavior of the total EBF, including the wall's shear strength and cracking patterns under loading.
Investigation of the Behaviour for Reinforced Concrete Beam Using Non Linear...IJMER
This study presents theoretical investigation that reinforced concrete and composite
construction might be suitably combined to give a new structural material : composite reinforced
concrete. To study theoretically the composite beam, non-linear three-dimensional finite elements
have been used to analyze the tested beam.
The 8-node brick elements in (ANSYS) are used to represent the concrete, the steel bars are modelled
as discrete axial members connected with concrete elements at shared nodes assuming perfect bond
between the concrete and the steel. The results obtained by finite element solution showed good
agreement with experimental results.
The main objective of the present investigation is to carry out a nonlinear analysis of reinforced
concrete beams resting on elastic foundation. Material nonlinearities due to cracking of concrete,
plastic flow, crushing of concrete and yielding of reinforcement are considered. Foundation
representation is assumed linear using Winkler model.
The reinforced concrete beam is modelled by using three dimensional finite elements with steel bars
as smeared layers. The examples have been chosen in order to demonstrate the applicability of the
modified computer program (Dynamic Analysis of Reinforced Concrete Beams on Elastic
Foundations DARCEF ) by comparing the predicted behaviour with that from other experimental and
analytical observations. The program modified in the present research work is capable of simulating
the behaviour of reinforced concrete beams resting of Winkler foundation and subjected to different
types of loading. The program solutions obtained for different reinforced concrete beams resting on
elastic foundations are in good agreement with the available results. Maximum percentage difference
in deflection is 15 %
Experimental Study, Simulation and Model Predictions of Recycled PET Strip-Re...IJERA Editor
This study presents results from a theoretical-experimental program of beams partially pre-stressed made with continuous recycled PET strip-reinforced concrete (plain concrete strength of 20 MPa). These studies mainly attempted to determine the stripinfluence in altering the flexural strength at first and final crack. Also the load-deflection, ductility, energy absorption capacity of the beams are observed and the studies can be used in predicting the flexural behavior of longitudinally reinforced concrete. The model theory assumes that concrete has a tensile load capacity different from zero, characterized by a uniaxial tensile stress-strain diagram. The need for non-linear geometric and the material models imply the use of numerical methods such as the finite element method; so that, a finite element analysis of reinforced concrete beam with strips-reinforced plastic is performed. The obtained results were compared with computer analysis and experimental data to corroborate the validity of the suggested method, showing that the theory also predicts correctly the post-cracking creep deformation.
A Review of Masonry Buckling CharacteristicsIJERA Editor
Masonry load bearing wall subjected to vertical concentric and eccentric loading may collapse through instability. In this Paper the buckling behaviour of masonry load bearing wall of different slenderness ratio were investigated by many researcher has been reviewed via testing a series of scale masonry wall subjected to concentric and eccentric vertical loading. It is also observed that buckling behaviour is greatly influenced by the material properties of units, mortar and units-mortar interface. The influence of nonlinear behaviour of interface element, slenderness ratio and various end conditions have been investigated together with the effect of different end eccentricity of vertical load
Finite Elements Modeling and Analysis of Double Skin Composite PlatesIOSR Journals
Abstract: Double skin composite (DSC) is a form of “steel/concrete/steel” sandwich structure; the steel plates
are connected to a sandwiched concrete core with welded stud shear connectors. In the present paper, a finite
element model for Double Skin Composite (DSC) panels subjected to quasi-static loading is developed. A series
of quasi-static finite elements models are used to analyze deformation and energy absorption capacity of such
system, when perforated by rigid penetrator with conical nose shape. Pilot test model is used to investigate the
failure pattern in the composite panel. The obtained results are compared to the experimental results; good
agreements are obtained between finite element and previous experimental results. Results show that such
elements have great ability of absorbing energy when subjected to perforation due to ductility of lower plate
skin and vertical stiffness of lower shear studs.
Structure failure often occurs in the structure of wall. This failure can adversely affect the comfort level of the structure. Knowing the behavior of structure resulting from the load is important, as it can help to predict the strength of the structure and comfort of the structure being worked on. One way to find out and predict the strength and comfort of the structure as a result of the load received is experimental test and simulation. The simulation VecTor2 used to predict the shear force, crack, and displacement of reinforced concrete wall when applied the load. This simulation considered the effect of bond stress-slip effect of behavior reinforced concrete. Bonds stress-slip gives a great influence on the strength and hysteretic response of the reinforced concrete wall. That is why this study considers the influence of bond stress-slip on reinforced concrete wall. All the result of simulation VecTor2 using bond stress-slip effect would be compared with the result of the experimental test to see the accuracy of the simulation test.
Investigation of the Behaviour for Reinforced Concrete Beam Using Non Linear...IJMER
This study presents theoretical investigation that reinforced concrete and composite
construction might be suitably combined to give a new structural material : composite reinforced
concrete. To study theoretically the composite beam, non-linear three-dimensional finite elements
have been used to analyze the tested beam.
The 8-node brick elements in (ANSYS) are used to represent the concrete, the steel bars are modelled
as discrete axial members connected with concrete elements at shared nodes assuming perfect bond
between the concrete and the steel. The results obtained by finite element solution showed good
agreement with experimental results.
The main objective of the present investigation is to carry out a nonlinear analysis of reinforced
concrete beams resting on elastic foundation. Material nonlinearities due to cracking of concrete,
plastic flow, crushing of concrete and yielding of reinforcement are considered. Foundation
representation is assumed linear using Winkler model.
The reinforced concrete beam is modelled by using three dimensional finite elements with steel bars
as smeared layers. The examples have been chosen in order to demonstrate the applicability of the
modified computer program (Dynamic Analysis of Reinforced Concrete Beams on Elastic
Foundations DARCEF ) by comparing the predicted behaviour with that from other experimental and
analytical observations. The program modified in the present research work is capable of simulating
the behaviour of reinforced concrete beams resting of Winkler foundation and subjected to different
types of loading. The program solutions obtained for different reinforced concrete beams resting on
elastic foundations are in good agreement with the available results. Maximum percentage difference
in deflection is 15 %
Experimental Study, Simulation and Model Predictions of Recycled PET Strip-Re...IJERA Editor
This study presents results from a theoretical-experimental program of beams partially pre-stressed made with continuous recycled PET strip-reinforced concrete (plain concrete strength of 20 MPa). These studies mainly attempted to determine the stripinfluence in altering the flexural strength at first and final crack. Also the load-deflection, ductility, energy absorption capacity of the beams are observed and the studies can be used in predicting the flexural behavior of longitudinally reinforced concrete. The model theory assumes that concrete has a tensile load capacity different from zero, characterized by a uniaxial tensile stress-strain diagram. The need for non-linear geometric and the material models imply the use of numerical methods such as the finite element method; so that, a finite element analysis of reinforced concrete beam with strips-reinforced plastic is performed. The obtained results were compared with computer analysis and experimental data to corroborate the validity of the suggested method, showing that the theory also predicts correctly the post-cracking creep deformation.
A Review of Masonry Buckling CharacteristicsIJERA Editor
Masonry load bearing wall subjected to vertical concentric and eccentric loading may collapse through instability. In this Paper the buckling behaviour of masonry load bearing wall of different slenderness ratio were investigated by many researcher has been reviewed via testing a series of scale masonry wall subjected to concentric and eccentric vertical loading. It is also observed that buckling behaviour is greatly influenced by the material properties of units, mortar and units-mortar interface. The influence of nonlinear behaviour of interface element, slenderness ratio and various end conditions have been investigated together with the effect of different end eccentricity of vertical load
Finite Elements Modeling and Analysis of Double Skin Composite PlatesIOSR Journals
Abstract: Double skin composite (DSC) is a form of “steel/concrete/steel” sandwich structure; the steel plates
are connected to a sandwiched concrete core with welded stud shear connectors. In the present paper, a finite
element model for Double Skin Composite (DSC) panels subjected to quasi-static loading is developed. A series
of quasi-static finite elements models are used to analyze deformation and energy absorption capacity of such
system, when perforated by rigid penetrator with conical nose shape. Pilot test model is used to investigate the
failure pattern in the composite panel. The obtained results are compared to the experimental results; good
agreements are obtained between finite element and previous experimental results. Results show that such
elements have great ability of absorbing energy when subjected to perforation due to ductility of lower plate
skin and vertical stiffness of lower shear studs.
Structure failure often occurs in the structure of wall. This failure can adversely affect the comfort level of the structure. Knowing the behavior of structure resulting from the load is important, as it can help to predict the strength of the structure and comfort of the structure being worked on. One way to find out and predict the strength and comfort of the structure as a result of the load received is experimental test and simulation. The simulation VecTor2 used to predict the shear force, crack, and displacement of reinforced concrete wall when applied the load. This simulation considered the effect of bond stress-slip effect of behavior reinforced concrete. Bonds stress-slip gives a great influence on the strength and hysteretic response of the reinforced concrete wall. That is why this study considers the influence of bond stress-slip on reinforced concrete wall. All the result of simulation VecTor2 using bond stress-slip effect would be compared with the result of the experimental test to see the accuracy of the simulation test.
Seismic Vulnerability Assessment of Steel Moment Resisting Frame due to Infil...IDES Editor
Steel moment resisting frame with open first storey
(soft storey) is known to perform well compared with the RC
frames during strong earthquake shaking. The presence of
masonry infill wall influences the overall behavior of the
structure when subjected to lateral forces, when masonry infill
are considered to interact with their surrounding frames the
lateral stiffness and lateral load carrying capacity of structure
largely increase. In this paper, the seismic vulnerability of
building with soft storey is shown with an example of G+10
three dimensional (3D) steel frame. The open first storey is
an important functional requirement of almost all the urban
multi-storey buildings, and hence, cannot be eliminated.
Hence some special measures need to be adopted for this
specific situation. The under-lying principle of any solution
to this problem is in increasing the stiffness’s of the first
storey such that the first storey stiffness is at least 50% as
stiff as the second storey, i.e., soft first storeys are to be avoided,
and providing adequate lateral strength in the first storey. In
this paper, stiffness balancing is proposed between the first
and second storey of a steel moment resisting frame building
with open first storey and brick infills as described in models.
A simple example building is analyzed by modeling it with
nine different methods. The stiffness effect on the first storey
is demonstrated through the lateral displacement profile of
the building.
This paper presents a study of finding the most effective position of RC structural
walls in an RC building to resist with seismic load. Structural walls without any opening
are used. By using Etabs, 5 models are created. Model 1 does not have any structural
wall. Model 2, 3, 4 and 5 consist of structural walls in different positions and they are
placed symmetrically in the plan view of the building. Story displacements, story-drifts
and overturning moments in x and y-directions are checked and compared to each other
to find the model which provides the highest stiffness. The calculation follows DPT
1302-61 code and Response spectrum equivalent static analysis method.
Instrumentation for finding seismic capacity of perforated infill wallEditorIJAERD
This research aims to find the effect of perforation on the lateral stability of reinforced concrete frame
structure. Unreinforced brick masonry (URBM) infill construction is very common practice in Pakistan. (URBM) is
experimentally evaluated in this paper that how perforations in frame structures with masonry infill affect the lateral
strength and over all stability, which include; Strength, Stiffness, Ductility and Energy dissipation response factor. A
total of two full scale Reinforced concrete frames with unreinforced brick masonry infill has been constructed. QuasiStatic cyclic testing performed on each infill wall Reinforced concrete frame with unreinforced brick masonry to find its
strength and stiffness. Perforation in infill walls reduced lateral strength and stiffness of frame structures considerably.
Composite Behaviour of Unbraced Multi-Storey Reinforced Concrete Infilled Fra...IJERA Editor
A comparative assessment on analytical outputs of the composite behavior of multi-storey reinforced concrete infilled frames using the macro models of the one-strut configuration and the finite element micro model is presented. The effect of openings in the infill was given particular attention in multi-storey building frames. The analysis demonstrated the simplicity of modified one-strut model, compared to the more complex multi strut and FE models while at the same time yielding highly accurate results. The introduction of the shear stress reduction factor clearly enhanced the efficiency of the one-strut model to reproduce the shear strength, lateral stiffness and seismic demand of infilled frames with openings.
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
Double Skin Composite (DSC) plates are subjected to impact required to cause complete perforation and the accompanied failure modes are investigated. The amount of energy absorbed is calculated by capturing the residual velocity of penetrator after perforating the lower plate. The difference in initial kinetic energy and residual kinetic energy is the amount of energy absorbed by the panel. In the present paper a non-linear three-dimensional finite element models for Double Skin Composite panels subjected to dynamic loading is introduced. Pilot model is used to investigate the failure pattern in the composite panel when subjected to impact loads by rigid steel penetrator, while the other models are used to analyze the energy absorption capacity of such system when perforated. Results showed that such elements have good ability of absorbing energy when subjected to perforation, due to ductility of lower plate skin and vertical stiffness of lower shear studs.
Analysis of Stress Concentration of Laminated Composite Plate With Circular Holeijiert bestjournal
Composite materials are finding a wide range of applications in structural design,especially for lightweight structure that have stringent stiffness and strength requirements. They are attractive replacement for metallic materials for many structural applications. By finding efficient composite str ucture design that meets all requirements of specific application. This is achieved by tailoring of material properties through selective choice of orientation,no. of stacking sequence of layers that make up composite material. Composites are used more and more often for load carrying and safety structures in all kind of applications foe aviation and space technology,for vehicles etc. Composite materials have been introduced progressively in automobiles,followingpolymer materials,a few of which have be en used as matrices. It is interestingto examine the relative masses of different materials which are used in theconstruction of automobiles. Even thoughthe relative mass of polymer - based materials appears low,one needs to take intoaccount that the specif ic mass of steel is about 4 times greater than that of polymers.This explains the higher percentage in terms of volume for the polymers.
Experimental Determination of Fracture Energy by RILEM Methodtheijes
This paper deals with investigation of fracture energy (GF) of concrete. The study involves experimental determination of fracture energy (GF) by testing three point bend concrete beams of same size but varying notch to depth ratios. RILEM fracture energy (GF) and Stress Intensity factor values is determined
Study of Linear and Non Linear Behavior of In filled FrameIJERA Editor
Reinforced concrete frame buildings often incorporate masonry infill panels as partitions to separate spaces
within a building or as cladding to complete the building envelope. However, the properties and construction
details of infilled panels can have a significant influence on the overall behavior of a structure. An infilled frame
typically consists of a steel or reinforced concrete frame with plain or reinforced brick masonry, block-work
infilling which restraint against lateral loads is provided by the composite action of the infill and the frame. With
the advancement of computational technology and ever going increasing trend of research activities, the demand
for inelastic design is increasing day by day. Since the brick masonry wall possesses highly heterogeneous, nonlinear
studies are inevitable. In this work, a study of non-linear behavior of reinforced concrete infilled frame
with brick masonry are carried out under lateral and combined loads using ANSYS software.
Steel-Concrete-Steel (SCS) sandwich composite wall entails steel face plates, inner-connected with specially welded shear studs and with steel plate edges, formulating a large concrete core encasement tube.
Research analysis based on FE models was conducted, in order to determine composite steel wall behaviour, as well as to unveil the influence that steel thickness and overall wall slenderness (i.e. aspect ratio) have on these walls.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Bamboo Reinforced Concrete Truss Bridge for Rural InfrastructureIJERA Editor
Bamboo is one of a potential renewable construction material in the village. Bamboo is known to have a high mechanical strength in direction of the fibers. The weakness of bamboo in lateral direction of the fiber could be solved by constructing a composite structure with the concrete. The appropriate construction with hold the loads in axial direction is a truss structure. In a bamboo concrete truss structure, the bars are composed from the concrete column with a bamboo reinforcement. The research studies about the performance of the bridge and the effect of loading position on the strain and deformation of bamboo reinforced concrete truss bridge. The bridge whose span and width are respectively 1.5 m and 1.2 m was prepared. Load applied to the truss bridge conducted by using vehicle load changes with position. Mounting the strains gauge in bamboo reinforcement of primary truss is to observe the strain. The LVDT is used to observe the deflection of the truss bridge. The results show that the loading position influences the strain and deformation as well as a theoretical view.
Reinforced concrete (RC) has become one of the most important building materials and is widely used in
many types of engineering structures. For the efficient use of RCC it is necessary to know the properties and the
behavior of RCC elements under various constrains. Within the framework of developing advanced design and
analysis methods for modern structures the need for experimental research continues
Summary of fracture mechanics problems analysis method in ABAQUSIJERA Editor
Fracture mechanics is the study of the strength of the materials or structures with crack and crack propagation regularity of a discipline. There are a lot of analysis function of ABAQUS, including fracture analysis. ABAQUS is very easy to use and easy to establish a model of the complicated problem. In order to effectively study of strong discontinuity problems such as crack, provides two methods of simulating the problem of cracks of ABAQUS. This paper describes the two methods respectively, and compare two methods.
“ Study of Sesmic Analysis of Masonry Wall Structure”IJERA Editor
Earthquakes are natural trouble under which disasters are mainly caused by damage or collapse of the structure and other man-made structures. When an earthquake occurs natural period of vibration is more on heavy loaded building and less in light loaded building. If the building is light weighted, i.e. steel is less then economy of structure is also achieved. Hence it is necessary to find out natural/fundamental time period when mass changes with different type of brick masonry and concrete masonry.This is necessary because IS 1893:2002 does not incorporate the effect of mass in a formula which they have mentioned for brick masonary structure. Thedesign will also analyze with ETAB software.
MODELLING OF AN INFILL WALL FOR THE ANALYSIS OF A BUILDING FRAME SUBJECTED TO...IAEME Publication
In general the analysis of a building frame is carried out with a bare frame but the presence of masonry infill in a framed structure results in high stiffness and influence the distribution of lateral load and also the response of the framed buildings. It can be noted that there is a large variation of mechanical properties of bricks. Masonry, a combination of brick and mortar, behaves in a highly nonlinear manner. The infill panel needs to be modelled in the analysis of a structural frame subjected to lateral load to obtain its true behaviour. In order to model the masonry infill, its properties required. In order to determine the properties of brick masonry compression tests were conducted on masonry infill panels and prisms.
Seismic Vulnerability Assessment of Steel Moment Resisting Frame due to Infil...IDES Editor
Steel moment resisting frame with open first storey
(soft storey) is known to perform well compared with the RC
frames during strong earthquake shaking. The presence of
masonry infill wall influences the overall behavior of the
structure when subjected to lateral forces, when masonry infill
are considered to interact with their surrounding frames the
lateral stiffness and lateral load carrying capacity of structure
largely increase. In this paper, the seismic vulnerability of
building with soft storey is shown with an example of G+10
three dimensional (3D) steel frame. The open first storey is
an important functional requirement of almost all the urban
multi-storey buildings, and hence, cannot be eliminated.
Hence some special measures need to be adopted for this
specific situation. The under-lying principle of any solution
to this problem is in increasing the stiffness’s of the first
storey such that the first storey stiffness is at least 50% as
stiff as the second storey, i.e., soft first storeys are to be avoided,
and providing adequate lateral strength in the first storey. In
this paper, stiffness balancing is proposed between the first
and second storey of a steel moment resisting frame building
with open first storey and brick infills as described in models.
A simple example building is analyzed by modeling it with
nine different methods. The stiffness effect on the first storey
is demonstrated through the lateral displacement profile of
the building.
This paper presents a study of finding the most effective position of RC structural
walls in an RC building to resist with seismic load. Structural walls without any opening
are used. By using Etabs, 5 models are created. Model 1 does not have any structural
wall. Model 2, 3, 4 and 5 consist of structural walls in different positions and they are
placed symmetrically in the plan view of the building. Story displacements, story-drifts
and overturning moments in x and y-directions are checked and compared to each other
to find the model which provides the highest stiffness. The calculation follows DPT
1302-61 code and Response spectrum equivalent static analysis method.
Instrumentation for finding seismic capacity of perforated infill wallEditorIJAERD
This research aims to find the effect of perforation on the lateral stability of reinforced concrete frame
structure. Unreinforced brick masonry (URBM) infill construction is very common practice in Pakistan. (URBM) is
experimentally evaluated in this paper that how perforations in frame structures with masonry infill affect the lateral
strength and over all stability, which include; Strength, Stiffness, Ductility and Energy dissipation response factor. A
total of two full scale Reinforced concrete frames with unreinforced brick masonry infill has been constructed. QuasiStatic cyclic testing performed on each infill wall Reinforced concrete frame with unreinforced brick masonry to find its
strength and stiffness. Perforation in infill walls reduced lateral strength and stiffness of frame structures considerably.
Composite Behaviour of Unbraced Multi-Storey Reinforced Concrete Infilled Fra...IJERA Editor
A comparative assessment on analytical outputs of the composite behavior of multi-storey reinforced concrete infilled frames using the macro models of the one-strut configuration and the finite element micro model is presented. The effect of openings in the infill was given particular attention in multi-storey building frames. The analysis demonstrated the simplicity of modified one-strut model, compared to the more complex multi strut and FE models while at the same time yielding highly accurate results. The introduction of the shear stress reduction factor clearly enhanced the efficiency of the one-strut model to reproduce the shear strength, lateral stiffness and seismic demand of infilled frames with openings.
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
Double Skin Composite (DSC) plates are subjected to impact required to cause complete perforation and the accompanied failure modes are investigated. The amount of energy absorbed is calculated by capturing the residual velocity of penetrator after perforating the lower plate. The difference in initial kinetic energy and residual kinetic energy is the amount of energy absorbed by the panel. In the present paper a non-linear three-dimensional finite element models for Double Skin Composite panels subjected to dynamic loading is introduced. Pilot model is used to investigate the failure pattern in the composite panel when subjected to impact loads by rigid steel penetrator, while the other models are used to analyze the energy absorption capacity of such system when perforated. Results showed that such elements have good ability of absorbing energy when subjected to perforation, due to ductility of lower plate skin and vertical stiffness of lower shear studs.
Analysis of Stress Concentration of Laminated Composite Plate With Circular Holeijiert bestjournal
Composite materials are finding a wide range of applications in structural design,especially for lightweight structure that have stringent stiffness and strength requirements. They are attractive replacement for metallic materials for many structural applications. By finding efficient composite str ucture design that meets all requirements of specific application. This is achieved by tailoring of material properties through selective choice of orientation,no. of stacking sequence of layers that make up composite material. Composites are used more and more often for load carrying and safety structures in all kind of applications foe aviation and space technology,for vehicles etc. Composite materials have been introduced progressively in automobiles,followingpolymer materials,a few of which have be en used as matrices. It is interestingto examine the relative masses of different materials which are used in theconstruction of automobiles. Even thoughthe relative mass of polymer - based materials appears low,one needs to take intoaccount that the specif ic mass of steel is about 4 times greater than that of polymers.This explains the higher percentage in terms of volume for the polymers.
Experimental Determination of Fracture Energy by RILEM Methodtheijes
This paper deals with investigation of fracture energy (GF) of concrete. The study involves experimental determination of fracture energy (GF) by testing three point bend concrete beams of same size but varying notch to depth ratios. RILEM fracture energy (GF) and Stress Intensity factor values is determined
Study of Linear and Non Linear Behavior of In filled FrameIJERA Editor
Reinforced concrete frame buildings often incorporate masonry infill panels as partitions to separate spaces
within a building or as cladding to complete the building envelope. However, the properties and construction
details of infilled panels can have a significant influence on the overall behavior of a structure. An infilled frame
typically consists of a steel or reinforced concrete frame with plain or reinforced brick masonry, block-work
infilling which restraint against lateral loads is provided by the composite action of the infill and the frame. With
the advancement of computational technology and ever going increasing trend of research activities, the demand
for inelastic design is increasing day by day. Since the brick masonry wall possesses highly heterogeneous, nonlinear
studies are inevitable. In this work, a study of non-linear behavior of reinforced concrete infilled frame
with brick masonry are carried out under lateral and combined loads using ANSYS software.
Steel-Concrete-Steel (SCS) sandwich composite wall entails steel face plates, inner-connected with specially welded shear studs and with steel plate edges, formulating a large concrete core encasement tube.
Research analysis based on FE models was conducted, in order to determine composite steel wall behaviour, as well as to unveil the influence that steel thickness and overall wall slenderness (i.e. aspect ratio) have on these walls.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Bamboo Reinforced Concrete Truss Bridge for Rural InfrastructureIJERA Editor
Bamboo is one of a potential renewable construction material in the village. Bamboo is known to have a high mechanical strength in direction of the fibers. The weakness of bamboo in lateral direction of the fiber could be solved by constructing a composite structure with the concrete. The appropriate construction with hold the loads in axial direction is a truss structure. In a bamboo concrete truss structure, the bars are composed from the concrete column with a bamboo reinforcement. The research studies about the performance of the bridge and the effect of loading position on the strain and deformation of bamboo reinforced concrete truss bridge. The bridge whose span and width are respectively 1.5 m and 1.2 m was prepared. Load applied to the truss bridge conducted by using vehicle load changes with position. Mounting the strains gauge in bamboo reinforcement of primary truss is to observe the strain. The LVDT is used to observe the deflection of the truss bridge. The results show that the loading position influences the strain and deformation as well as a theoretical view.
Reinforced concrete (RC) has become one of the most important building materials and is widely used in
many types of engineering structures. For the efficient use of RCC it is necessary to know the properties and the
behavior of RCC elements under various constrains. Within the framework of developing advanced design and
analysis methods for modern structures the need for experimental research continues
Summary of fracture mechanics problems analysis method in ABAQUSIJERA Editor
Fracture mechanics is the study of the strength of the materials or structures with crack and crack propagation regularity of a discipline. There are a lot of analysis function of ABAQUS, including fracture analysis. ABAQUS is very easy to use and easy to establish a model of the complicated problem. In order to effectively study of strong discontinuity problems such as crack, provides two methods of simulating the problem of cracks of ABAQUS. This paper describes the two methods respectively, and compare two methods.
“ Study of Sesmic Analysis of Masonry Wall Structure”IJERA Editor
Earthquakes are natural trouble under which disasters are mainly caused by damage or collapse of the structure and other man-made structures. When an earthquake occurs natural period of vibration is more on heavy loaded building and less in light loaded building. If the building is light weighted, i.e. steel is less then economy of structure is also achieved. Hence it is necessary to find out natural/fundamental time period when mass changes with different type of brick masonry and concrete masonry.This is necessary because IS 1893:2002 does not incorporate the effect of mass in a formula which they have mentioned for brick masonary structure. Thedesign will also analyze with ETAB software.
MODELLING OF AN INFILL WALL FOR THE ANALYSIS OF A BUILDING FRAME SUBJECTED TO...IAEME Publication
In general the analysis of a building frame is carried out with a bare frame but the presence of masonry infill in a framed structure results in high stiffness and influence the distribution of lateral load and also the response of the framed buildings. It can be noted that there is a large variation of mechanical properties of bricks. Masonry, a combination of brick and mortar, behaves in a highly nonlinear manner. The infill panel needs to be modelled in the analysis of a structural frame subjected to lateral load to obtain its true behaviour. In order to model the masonry infill, its properties required. In order to determine the properties of brick masonry compression tests were conducted on masonry infill panels and prisms.
Unconventional Gas and Hydraulic Fracturingfnfnlands
This presentation was made by Hydrogeologist Gilles Wendling at Keepers of the Water VI in Fort Nelson, BC. This event was hosted by Fort Nelson First Nation.
DESIGN AND ANALYSIS OF BRIDGE WITH TWO ENDS FIXED ON VERTICAL WALL USING FIN...IAEME Publication
The Finite element analyses are conducted to model the tensile capacity of steel fiber-reinforced concrete (SFRC). For this purpose bridge with two ends fixed one specimen are casted and tested under direct and uni-axial tension. Two types of aggregates (brick and stone) are used to cast the SFRC and plain concrete. The fiber volume ratio is maintained 1.5 %. Total 8 numbers of dog-bone specimens are made and tested in a 1000-kN capacity digital universal testing machine (UTM). The strain data are gathered employing digital image correlation technique from high-definition images and high-speed video clips. Then, the strain data are synthesized with the load data obtained from the load cell of the UTM.
A Study on Effect of Sizes of aggregates on Steel Fiber Reinforced ConcreteIJERD Editor
Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and
little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of
multidirectional and closely spaced reinforcement, which can be provided in the form of randomly distributed
fibers. Steel fiber is one of the most commonly used fibers The present experimental study considers the effect
of aggregate size and steel fibers on the modulus of elasticity of concrete. Crimped steel fibers at volume
fraction of 0%.0.5%, 1.0% and 1.5% were used. Study on effect of volume fraction of fibers and change of
aggregate size on the modulus of elasticity of concrete was also deemed as an important part of present
experimental investigation. This work aims in studying the mechanical behavior of concrete in terms of modulus
of elasticity with the change of aggregate size reinforced with steel fibers of different series for M30 and M50
grade concretes. The results obtained show that the addition of steel fiber improves the modulus of elasticity of
concrete. It was also analyzed that by increasing the fiber volume fraction from 0%, to 1.5% there was a healthy
effect on modulus of elasticity of Steel Fiber Reinforced concrete.
Anartificial Neural Network for Prediction of Seismic Behavior in RC Building...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Finite Element Modeling of a Multi-Storeyed Retrofitted Reinforced Concrete F...IOSR Journals
In the present study, the non-linear response of RC frame using FE modeling under the incremental
loading has been carried out in the first phase of analysis to study the response and load-carrying capacity of a
four storeyed RC frame using non-linear finite element analysis. In the second phase of study an analysis model
for retrofitted RC frame using finite element method using software ATENA is presented. The results obtained
from FE analysis in both cases are compared with the experimental data for four storeyed RC frame tested by
BARC at CPRI. The results from finite element analysis were calculated at the same location as used in
experimental test. The accuracy of the finite element model is assessed by the comparison with experimental
results which are to be in good agreement. The base shear/ displacement curves from finite element analysis
agree well with the experimental results in linear range. The maximum difference in base shear is observed to
be 7.9%
Finite element analysis of innovative solutions of precast concrete beamcolum...Franco Bontempi
Especially to precast concrete structure connections are one of the most essential parts. Connections transfer forces between precast members, so the interaction between precast units is obtained. They are generally the
weakest link in the structure. An acceptable performance of precast concrete structure depends especially on the
appropriate kind of connections choice, adequate detailing of components and design of the connections is fundamental. It is interesting to study the behavior of connecting elements and to compare different solutions of ductile connections for precast concrete structures in case of horizontal applied force and vertical imposed displacement, as well as those produced by hazards situation, like that earthquake and explosion, whereby topics of structure robustness are carried out. The case of study is an innovative dissipative system of connection between precast concrete elements, usable for buildings and bridges, the investigation of these topics is carried out by F.E.A. by program DIANA with comparison with results obtained independently with ASTER.
Effectiveness Evaluation of Seismic Protection Devices for Bridges in the PB...Franco Bontempi
Seismic protection measures for bridges can be used both for obtaining acceptable performances from new structures that for retrofitting existing ones. With the modern design philosophy based on probabilistic Performance-Based Earthquake Engineering (PBEE) approaches, the engineers are allowed to investigate different design solutions in terms of vulnerability assessment. However, if probabilistic PBEE approaches are nowadays well established and widely studied also for bridges, the topic of using the PBEE frameworks for the evaluation of the effectiveness of seismic protection devices for bridges is not extensively treated in literature.
The first objective of this work is to deal with the problem of assessing the earthquake performance of an highway bridge equipped with different bearing device: the
elastomeric bearings (ERB) and the friction pendulum systems (FPS). The second purpose is to evaluate the efficiency of a structure-dependent IM in case of isolated system. The examined structure is an highway bridge with concrete piers and steel truss deck. A FE model of the bridge is developed by using nonlinear beam-column elements with fiber section and the devices are modeled by specific elements implementing their
nonlinear behavior. The effectiveness of the different retrofitting strategies has been carried out in terms of damage probability. Choosing the example of slight damage, and referring to the curvature ductility as EDP, the probability of damage during a period of 50 years is: 23% for the structure without isolation, 7% for the structure equipped with ERB, and 3% for the structure equipped with FPS isolation.
Numerical investigations on recycled aggregate rc beamseSAT Journals
Abstract One of the major challenges in our present society is the protection of environment. Some of the important elements in this respect are reduction in the consumption of energy and natural raw materials. The use of recycled aggregates from construction and demolition waste has been receiving increased attention in recent sustainable construction environment. However the question that needs to be addressed is whether one can consistently produce good quality concrete using recycled aggregates (RA). Strength, stiffness and durability characteristics of structural components built using recycled aggregates are required to be studied carefully. Towards this, a static nonlinear finite element analysis is carried out to understand the behavior of reinforced concrete beam made with Recycled aggregate to the extent of 50% replacement of total aggregate volume. Flexural load is applied on the beams. The capacity in terms of strength and stiffness are discussed. Equivalent stress strain graph is derived using moment curvature relationship. Equivalent model is validated by comparing with experimental results available in literature. Response from numerical investigation indicates that Recycled aggregate can be used as structural members. Keywords: - Recycled aggregates, Construction and demolition waste, Reinforced concrete, Moment curvature, Equivalent Stress strain relationship, nonlinear analysis
A Study of R. C. C. Beam Column Junction Subjected To QuasiStatic (Monotonic)...IOSR Journals
Abstract - Beam and column where intersects is called as joint or junction. The different types of joints are
classified as corner joint, exterior joint, interior joint etc. on beam column joint applying quasi-static 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) Significant experimental research has been
conducted over the past three decades on hysteretic behavior of beam-column joints of RC frames under cyclic
displacement loading. 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
Ultimate strength of composite beam with web openings subjected to combined n...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
Non Linear Analysis of Composite Beam Slab Junction with Shear Connectors usi...inventionjournals
Frame finite-element models permit obtaining, at moderate computational cost, significant information on the dynamic response behavior of steel–concrete composite beam frame structures. As an extension of conventional monolithic beam models, composite beams with deformable shear connection were specifically introduced and adopted for the analysis of composite beams, in which the flexible shear connection allows development of partial composite action influencing structural deformation and distribution of stresses. The use of beams with deformable shear connection in the analysis of frame structures raises very specific modeling issues, such as the characterization of the cyclic behavior of the deformable shear connection and the assembly of composite beam elements with conventional beam–column elements. In addition, the effects on the dynamic response of composite beam frame structures of various factors, such as the shear connection boundary conditions and the mass distribution between the two components of the composite beam, are still not clear and deserve more investigation. The object of this paper is to provide deeper insight into the natural vibration properties and nonlinear seismic response behavior of composite beam frame structures and how they are influenced by various modeling assumptions. For this purpose, a materially nonlinear-only finite-element formulation is used for static and dynamic response analyses of steel–concrete frame structures using composite beam elements with deformable shear connection. Realistic uniaxial cyclic constitutive laws are adopted for the steel and concrete materials of the beams and columns and for the shear connection. The resulting finite-element model for a benchmark problem is validated using experimental test results from the literature review
Non Linear Analysis of Composite Beam Slab Junction with Shear Connectors usi...
14 05 01-0432
1. The 14
th
World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
A Study of the Effect of Infilled Brick Walls on the Behavior of Eccentrically
Braced Frames
Saedi Daryan A1
, Ziaei M2
, Golafshar A3
, Pirmoz A4
1,2.3,4
Dept. of Civil Engineering , K.N.Toosi University of Technology, Tehran, Iran
Email: Masoodz.z@gmail.com
ABSTRACT :
Eccentrically Braced Frames (EBFs) are usually infilled by masonry walls, but in common design, the stiffness
and lateral resistance of these walls is ignored. In this study, a proper model is developed using explicit finite
elements method to study the behavior of EBFs with infilled masonry wall. Because of complicated mechanical
and geometrical properties of masonry walls and also because of the interaction between steel frame and masonry
wall, this model is not easy to obtain. To ensure the ability of the model to precisely simulate the behavior of an
EBF with infilled brick wall, initial models were made and the problems were solved comparing the results of
experimental test and the results of these initial models. Material models and some basic principles of explicit
finite element algorithm are used and three initial models were made: a model of a brick wall without EBF, a
model of an EBF without infilled brick wall and finally a model of an EBF with infilled brick wall. Using these
three initial models, constitutive model for masonry and steel material, and also the proper elements for modeling
the behavior of mortar are obtained. Then the final model of an EBF with infilled brick wall is made and the
influence of brick wall on the behavior of total frame is studied. In addition, shear strength and cracking pattern
of masonry wall under static loading is studied.
KEYWORDS: Eccentrically braced frame, infilled brick wall, explicit finite element method
2. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
1. Introduction
In an eccentrically braced frame, axial forces induced in the braces are transferred either to a column or another
brace through shear and bending in a segment of the beam called link beam. These link beams act to dissipate the
large amount of input energy of a severe seismic event via material yielding.
These frames are usually infilled by masonry walls but in common design, the influence of these walls on the
behavior of total frame is ignored. These infilled walls may have a significant influence on the stiffness and the
strength of eccentrically braced frames. In a well designed EBF, inelastic action is limited just to the link beam
and the other members remain in the elastic range during an earthquake. The existence of a masonry wall may
influence the action of link beam, so the behavior of these frames should be studied considering the effects of
infilled masonry walls. Although there are several studies about eccentrically braced frames and masonry walls,
study about the eccentrically braced frame with infilled wall is rare.
Also experimental tests provide reliable data which can determine the real behavior of the frame with infilled
wall, in many cased conducting experimental test is very expensive or impossible. Another disadvantage of
experimental test is that mechanical and geometrical parameters are limited in the tests.
Because of the advances in numerical methods, simulation of complicated real structures became possible.
Among the numerical methods, the explicit finite element method is a powerful method for studying and
modeling an eccentrically braced frame with infilled masonry wall. In this article a finite element model for an
eccentrically braced steel frame is made and compared to the same frame which has the infilled wall.
ABAQUS finite element program is used for parametric modeling of specimens. Firstly, the analysis of the frame
without masonry wall was carried out by standard method and the model was verified using the results of
experimental tests. Then the EBF model was made with and without infilled masonry wall and the analysis was
done by explicit finite element method and the results were compared to the results of experimental tests to
assure the ability of the explicit finite element method for simulating the complicated mechanical and geometrical
properties and also the interaction between masonry and steel material in the frame. After verifying the models,
final model was made to study the behavior of an eccentrically braced frame with infilled brick wall.
2.1 Details of Bruneau and Berman test
Bruneau and Berman in 2006 studied the effect of using box section as the link beam in eccentrically braced
frames. In usual design, wide flange sections are used for link beams, but since it is impossible to provide lateral
bracing in bridges to prevent lateral-torsion buckling, box section was used to eliminate the need for the lateral
bracing, because box sections have significant torsional strength. This test was selected for verifying the finite
element models. The test setup is shown in figure 1.
Figure 1: test setup used by Bruneau and Berman
2.2 Finite element model and material properties
Shell elements were used to make the frame model. As it can be seen in figure1, the frame is simply supported
and the load is applied through a beam which is connected to the frame by a hinge. For simulating the base
support condition and load applying method, the connection of columns to the base is modeled in a way to act
like a hinge. The same condition is made at the top of the columns to simulate the exact load applying method
used in the experimental test. The finite element model is shown in figure 2. To prevent local buckling, stiffeners
are placed around the beam since box section is used as the beam in this frame. The model is analyzed using
standard method.
3. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
Figure 2: Finite element model of the eccentrically braced frame
2.3 Verifying the model
A comparison is made between the results of the experimental test and the results of finite element model
analysis which is shown in figure 3. As it can be seen, there is a good agreement between the results. Finite
element model had the ability to predict the peak point and also the initial stiffness of the curve.
0
100
200
300
400
500
600
700
800
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Rotation(rad)
Force(kN)
Finite element model
Experimental Test
Figure 3: force-displacement obtained by experimental test and finite element model
3.1 Masonry panel
The complex mechanical behavior of masonry structures is the result of their non-homogenous and brittle material
properties, as well as its geometric intricacy: masonry is composed of aligned, uniformly dispersed units connected
by a regular array of bed and head mortar joints. These mortar joints are the weakness of the assembly and exhibit
notable material nonlinearity and significantly influence the response of masonry. The nonlinear characteristics of
the mortar joints initially result from the nonlinear deformation characteristics of the joints under shear and
compression but are exaggerated by local failure, opening-closing, dilatancy and slip of the joints.
Two mechanical approaches, macro- and micro- modeling, have been adopted by researchers to formulate an
appropriate constitutive description of masonry structures. The macro-modeling approach neglects the distinction
between units and mortar joints by taking into account the effect of discrete joints in an average sense through
homogenization techniques such as those presented by Dhanasekar et al. (1985) and Middleton et al. (1991).
Generally, this approach is recommended for the analysis of large masonry structures because of the inability to
exert detailed stress analysis and capture the various failure mechanisms of masonry assemblages. Gambarotta et
al. (1997 a/b) adopted a refined approach in which the wall was simulated as an equivalent stratified medium made
up of layers representative of the mortar bed joints and of the units and head joints, respectively.
Alternately, the micro-modeling approach is a computationally intensive approach. A large number of elements are
required because the masonry structure is modeled as a discontinuous assembly of blocks connected by appropriate
discrete joints. The joints are simulated by appropriate constitutive interface elements so that considerations such as
the initiation of fracture, propagation of cracks and sliding at interfaces with different levels of refinement of the
assemblage can be taken into account. Therefore, a more realistic and rigorous analysis can be expected since it
4. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
allows locating exact joint positions and adopting appropriate constitutive models for the blocks and interfaces. Ali
et al. (1988), Anand et al. (1990) and Rots (1991) adopted a refined approach in which both the masonry units and
the mortar joints are discretely modeled with continuum elements. The significant computational intensity of this
level of refined analysis restricts its application to small laboratory specimens. In a less-refined approach, Arya et
al. (1978), Page (1978), and Gambarotta et al. (1997a) modeled mortar joints with zero thickness interface
elements and masonry units with enlarged continuum elements to account for the space formerly occupied by
mortar joints. The approach with this level of refinement is also computationally intensive for the analysis of large
masonry structures. Furthermore, Formica et al. (2002) pointed out that the interface elements are only suitable for
a small displacement field as a result of their inability to provide easy remeshing to update existing contacts and/or
to create new ones when the motion is large.
Considering the above concepts and the accuracy needed in this study for simulating the initiation of failure,
crack propagation and slippage in different surfaced, the micro method was selected for modeling the behavior of
infilled brick wall.
Masonry shear walls are generally tested in the lab using quasi-static loading history in order to gain better
understanding of the failure pattern and deformation characteristics including measure of ductility. As such they
are modeled using static perturbation finite element modeling techniques based on implicit methods. Such finite
element analyses of masonry walls in general, although have provided much insight into the behavior of masonry
shear walls, have been regarded as too cumbersome and inefficient in terms of the time taken for the analysis as
well as the complexities of the modeling strategies. These conventional implicit techniques require solution of
equilibrium equations containing full stiffness matrix of the structure; as such they are very time consuming.
Furthermore, as the masonry cracks the stiffness matrix tend to become ill conditioned posing a convergence
problem. This paper presents a computationally efficient explicit finite element modeling technique that is
capable of simulating highly nonlinear events. The explicit finite element modeling technique never requires a
fully assembled system stiffness matrix; rather it solves for the internal variables using the theory of dynamic
wave propagation in solids. Although explicit technique is more suitable for high dynamic events such as impact,
quasi-static load tests could also be simulated if due care is taken to minimize the kinetic energy due to rapid
cracking/load shedding. As iterations are not performed, much smaller increments of the applied load are required
for the explicit technique to provide acceptable results. Converged solutions obtained from this technique are
based on satisfaction of the global energy equilibrium equations; as such it is suitable where the global structural
behavior, such as the deformation and failure characteristics, is of prime importance.
3.2Critical time increment
In time integration methods, choosing a proper time increment is definitely important. Small time steps are
necessary to obtain accurate and stable responses.
ABAQUS/EXPLICIT generally requires 10,000–1,000,000 increments to achieve converged solutions, but the
computational cost per increment is generally relatively small. For accuracy, the time increment was kept quite
small. Maximum time increment used by the explicit solver related to the stability limit of the structure globally
is calculated from the natural frequency corresponding mode shapes of a dynamic system. The loading time was
increased up to 100 times the period of the lowest mode. By artificially increasing the step time the velocities and
the kinetic energy were minimized.
In the followings, to verify the masonry infilled wall models, the experimental tests carried out by Vitorino et al.
were selected and the finite element models were made according to the specimens tested in this experimental
study and the models were analyzed using explicit finite element method.
To construct the wall specimens in the experimental test, a layer of mortar was poured on the slab at first and then
the wall is constructed. Then a concrete beam is installed on the wall and finally measuring instruments were
installed on the wall.
The walls were tested after drying. The vertical compression load is applied by a 1000 KN capacity hydraulic
actuator using force control method. The rate of loading was 1 KN per second. When the vertical load reached to
the specific value, it is kept constant and the lateral load is applied to the specimens by applying small
displacements.
3.4 finite element model and material properties
Two kinds of elements were used to model masonry panels, eight-node solid elements were used to model the
bricks and contact elements were used to simulate the mortar. It was assumed that the panel behaves nonlinearly
5. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
under applied displacement. The mortar was modeled using interaction element in ABAQUS which allows for
small relative slippage in the contact surface. The properties of this element are defined according to the
properties of mortar in the experimental test. In the following figure finite element model and sub-structures are
shown. The model meshing was fine enough to obtain accurate results. Material properties used in the test are
tabulated in table 1.
Table 1: material properties of the specimens used in Vitorino tests
Material Poisson ratio Ultimate stress
(N/mm2)
Modulus of elasticity (N/mm2)
Block 0.2 57 15500
3.5 verification of the model
Force-displacement curves and cracking pattern of masonry panels obtained by finite element model is compared
to those obtained by the experimental test. Figure 4 shows a comparison between the cracking pattern obtained
by finite element model and experimental test. Failure modes show the relation between vertical load and crack
pattern. In the specimens with fewer vertical loads, the failure of wall is in the form of cracks in the seams and no
fracture occurred in the blocks. But in the specimens with higher vertical loads, diagonal cracks appeared and
there were some fractures in the blocks. In general, it can be concluded that failure mechanism in wall is in the
form of diagonal cracks and fracture of some panels and when the vertical load is increased the probability of
block fracture increases. Force-displacement response obtained by finite element modeling and experimental tests
is shown in figure 5. It can be observed that force-displacement respond curves have good agreement both in
elastic and plastic ranges. This agreement shows the ability of explicit finite element to accurately predict the
behavior of masonry panels. .The difference between the results of modeling and experimental test in nonlinear
range is due to several parameters such as simplifications used in finite element model, defects in experimental
tests, residual stress and especially nonlinear constitutive laws used in finite element modeling.
Figure 4: crack pattern in brick panel
0
2
4
6
8
10
12
14
16
18
0 5 10 15
Displacement (mm)
Load
(kN)
EXP
FE-SW30
Figure 5: force-displacement curve of the tests carried out by Vitorino
0
20
40
60
80
100
120
0 2 4 6 8 10
Displacement (mm)
Load
(KN)
EXP
FE-SW2
6. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
4. Steel frame with infilled brick wall
Considering the prevalent application of masonry material in structures and their determinant role in stiffness and
strength of structures, many studies have been carried in this field. In some of these studies, masonry panels are
investigated separately and in some others, masonry materials are studied as infilled walls surrounded by steel
frame( like the real situation of masonry panels in structures). The latter studies present more realistic results and
applied forces and cracking pattern are closer to the real behavior of structural frames. In recent years this method
of study is more used. For example, experimental tests have been carried out by Moghaddam et al. on steel
frames infilled by masonry and concrete walls. In this study, the results of this experimental test are used to verify
the finite element models. These models are analyzed using explicit finite element method.
4.1 Details of the selected experimental test
Moghaddam et al. tested 11 steel frame specimens infilled by masonry and concrete walls under cyclic loading.
One of these specimens which is a steel frame with masonry wall is selected to verify finite element models.
4.2 Finite element model and material properties
Brick panel is modeled using eight-node solid elements and contact elements are used to model the mortar. It is
assumed that the panel behaves nonlinear under applied displacement. The mortar between the bricks is modeled
using interaction element in ABAQUS which allows for little relative slippage in the contact surface. The
properties of this element are defined according to the properties of mortar in the test specimens. Steel frame
modeling is done using shell elements. To obtain accurate results, the meshing of finite element model was fine
enough.
4.3 finite element verification
Force-displacement curves obtained by experimental test and finite element model are compared in figure 6.
Initial stiffness and ultimate load in the two curves are close to each other which verify that explicit finite element
method is precisely capable of simulate the behavior of masonry walls. Crack pattern in the finite element model
is diagonal which is similar to those observed in experimental test carried out by Moghaddam et al.
-20
0
20
40
60
80
100
120
140
160
180
0 20 40 60 80 100 120
Displasement (mm)
Load
(kN)
EXP
FE
Figure 6: force-displacement obtained by experimental test carried out by Moghaddam et al.
5. Final finite element models
Using the initial finite element models, the capability and the accuracy of explicit finite element method to
precisely simulate the behavior of steel frames with masonry wall is verified. Then six eccentrically braced frame
finite element models are made and the analysis results of EBF with and without masonry wall are compared. It
should be noted that large span frame models are analyzed in two cases. In the first case, the masonry wall is not
braced in out of plane direction (SML3.4 ,SML2.8). In the second case, the brick wall is braced in out of plane
direction, as it is required in seismic provisions (SML3.4*, SML2.8*).
6. present the results obtained from analysis of the models
The results obtained from the analysis of the models are shown in figure7 as force-displacement curves. In this
figure, force-displacement curves are shown for some frame model with and without masonry wall.
7. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
Figure 7: a comparison between force-displacement curves of frames with and without masonry wall
If the collapse limit of the structures is assumed to be the drift equal to 2% of structure height, as it is obvious
from the figures, the masonry wall significantly affects the behavior of EBF. When the masonry wall does not
exist, the frame dissipates a little part of input energy in elastic range and most of it in plastic range and so the
frame has a full ductile behavior. But the behavior of the frames changes when the infilled brick wall exists. The
presence of masonry wall affects both strength and lateral displacement of eccentrically braced frame. The
stiffness and the strength of frame in elastic range increase significantly, but when the total system enters in
plastic mode, after a little increase, the strength of frame decreases significantly due to fragile behavior of
masonry wall. Because of principle cracking of masonry wall or sometimes collapse of it, steel frame and
masonry wall do not behave as a united system and the increase in strength observed after the mentioned fall is
only because of steel frame. To compare the results of steel frames with and without masonry wall, it should be
said that in the case where masonry wall exists the displacement in which the total system yields is higher, but
since the plastic range in force-displacement force is decreased significantly, the total displacement capacity of
the frame is decreased.
The rotation capacity of the frame with brick wall is significantly decreased compared to the rotation capacity in
bare steel frame. Except two frames, the fracture of masonry wall occurred before the link beam can reach the
required rotation capacity of shear link beams (0.08 rad) and this shows that the frames are not ductile enough.
It should be noted that deformed shape of SMS and SMI specimens are similar and deformed SML specimens are
similar to each others.
Figure 8: Deformed shapes of specimens SL3.4 and SML3.
As it can be seen in figure 8, the presence of bracings prevented the occurrence of diagonal cracks which usually
occur in masonry walls. At the top of the space formed between two braces, horizontal cracks were observed in
all specimens who were the main cause of wall fracture in small and medium and out of plane braced large span
frames. In large span frames without out of plane bracing, the wall has displacement in out of plane direction in
middle part which is the main failure mode of the wall.
7. conclusion
In this study, explicit finite element method is proposed for modeling and analyzing eccentrically braced frames
with masonry infilled walls.
Firstly, the model of single brick wall and model of EBF with infilled wall were made and these models were
analyzed by explicit finite element method. Comparing the results of these models and the results of experimental
8. The 14
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World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
tests, good agreement was observed and the ability of models to precisely simulate the behavior of EBFs is
verified. Then the ability of explicit finite element method to present mechanical behavior and complicated
geometry of masonry materials and to simulate the interaction between steel frame and masonry wall was
assured. The study confirmed that such models can be used to predict crack pattern, failure modes, initial stiffness
and ultimate load. In addition, explicit finite element model present rational stress distribution at critical points
such as wall heel and central part of the wall. After verifying the finite element models, the influence of masonry
infilled wall on the behavior of eccentrically braced frames is studied. This investigation showed that in general,
the presence of masonry wall increases the yield strength and the elastic range in the force-displacement curves.
But the plastic behavior of the frame is deteriorated and due to fragile behavior of masonry materials, the total
system of steel frame and masonry wall has a significant strength fall when the elastic range is passed. By
decreasing the plastic range, the behavior of the frame is no more ductile and so the energy dissipation of the
frame with masonry wall is significantly smaller when compared to those of a steel frame without masonry wall.
In the case of crack pattern and failure mode of brick panels, it can be said that for small, medium and out of
plane braced large span frames, the crack pattern is in the form of the horizontal propagation of cracks. For large
span frames without out of plane bracing, the main cause of the fracture of the wall is out of plane deformations.
In conclusion, it can be said that the effect of masonry infilled walls should be considered in design of
eccentrically braced frames.
References
J.W. Berman, M. Bruneau, 2007,"Experimental and Analytical Investigation of Tubular Links for Eccentrically
Braced Frames", Engineering Structures 29, pp. 1929-1938
Ziaei M, 2007,"Study the Stability of K-shape Eccentrically Braced Frames in shear in Plastic Mode", Master
thesis, K.N.Toosi university of technology, Tehran, Iran
Dhanasekar M., Kleeman P. W. and Page A. W., "Biaxial Stress-Strain Relations for Brick Masonry." Journal of
Structural Engineering, ASCE, 111(5), pp. 1085 -1100, 185.
Middleton J., Pande G. N., Liang J. X. and Kralj B., 1991, "Some Recent Advances in Computer Methods in
Structural Masonry" Computer Methods in Structural Masonry, J. Middleton and G. N. Pande, eds., Books and
Journals International, Swansea, U.K., pp. 1-21
Gambarotta L. and Lagomarsino S., 1997, "Damage Models for the Seismic Response of Brick Masonry Shear
Walls" Part II: The Continuum Model and its Applications,” Earthquake Eng. and Structural Dynamics, 26(4), pp.
441-462
Ali S. S. and Page A. W., 1988, "Finite Element Model for Masonry Subjected to Concentrated Loads" Journal of
Structural Engineering, ASCE, 114(8), 1,761-1,784
Anand S. C. and Rahman M. A., 1990, "Interface Behavior in Concrete Block Mortar Joints - a Comparison of
Analytical and Experimental Results." Proceedings 5th North Am. Masonry Conference, University of Illinois,
Urbana-Champaign, IL, June3-6, 475-486
Rots J. G., 1991, "Numerical Simulation of Cracking in Structural Masonry", Heron, 36(2), pp. 4-63
Arya S. K. and Hegemier G. A., 1978, "On Nonlinear Response Prediction of Concrete Masonry Assemblies",
Proceedings 1st North American Masonry Conference, The Masonry Society, Boulder, CO, August 14-16,
1.1-1.24
Page A. W., 1978, "Finite Element Model for Masonry", Journal of Structural Engineering, ASCE, 104(8), pp.
1,267-1,285
Gambarotta L. and Lagomarsino S., 1997, "Damage Models for the Seismic Response of Brick Masonry Shear
Walls. Part I The Mortar Joint Model and its Applications" Earthquake Eng. and Structural Dynamics, 26(4), pp.
423-43
Formica G., Sansalone V. and Casciaro R., 2002, "A Mixed Solution Strategy for the Nonlinear Analysis of Brick
Masonry Walls." Computer Methods in Applied Mechanics and Engineering, 11(51-52), pp. 5,847-5,876
Vitorino D., 2003, Experimental and numerical Analysis of Blocky Masonry Structures under Cyclic Loading,
Ph.D. Thesis, University of Minho
ABAQUS finite element software manual
H.A. Moghadam, M.Gh. Mohammadi, M. Ghaemian., 2006, Experimental and analytical investigation into crack
strength determination of infilled steel frames. Journal of Constructional Steel Research, 62 pp.1341-1352.