Pub Date : 2021-01-02DOI: 10.1080/13287982.2021.1872992
A. Al-Mosawe, R. Al-Mahaidi, Dia Alwash, X. Zhao
ABSTRACT Pre-stressed unbonded retrofit (PUR) CFRP strengthening of steel structures is becoming a common method of strengthening metallic structures. This paper presents a comprehensive study on the use of the PUR CFRP-strengthening method for strengthening a steel bridge in Melbourne, Australia. Finite element analysis is performed in this study to model the entire bridge and the strengthened element, and the model is validated using actual on-site measurements which showed the stress developments of two girders before and after strengthening when a fully loaded truck passed over the bridge. A parametric study is performed to investigate the stress development of steel girders strengthened with the PUR system under different girder-deck levels of rigidity. The results showed a perfect match between the finite element modelling and actual measurements, and the effectiveness of the PUR system under critical conditions such as different girder-deck stiffness connection levels.
{"title":"Finite element simulation of unbonded retrofitting system for a steel bridge in Australia","authors":"A. Al-Mosawe, R. Al-Mahaidi, Dia Alwash, X. Zhao","doi":"10.1080/13287982.2021.1872992","DOIUrl":"https://doi.org/10.1080/13287982.2021.1872992","url":null,"abstract":"ABSTRACT Pre-stressed unbonded retrofit (PUR) CFRP strengthening of steel structures is becoming a common method of strengthening metallic structures. This paper presents a comprehensive study on the use of the PUR CFRP-strengthening method for strengthening a steel bridge in Melbourne, Australia. Finite element analysis is performed in this study to model the entire bridge and the strengthened element, and the model is validated using actual on-site measurements which showed the stress developments of two girders before and after strengthening when a fully loaded truck passed over the bridge. A parametric study is performed to investigate the stress development of steel girders strengthened with the PUR system under different girder-deck levels of rigidity. The results showed a perfect match between the finite element modelling and actual measurements, and the effectiveness of the PUR system under critical conditions such as different girder-deck stiffness connection levels.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"32 1","pages":"29 - 41"},"PeriodicalIF":1.1,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88434846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/13287982.2020.1862973
P. Lu, Chenhao Zhou, Simin Huang, Dengguo Li
ABSTRACT The seamless expansion joint has received considerable attention as a new type of bridge expansion joint owing to its good integrity and driving comfort. To satisfy the requirements of both deformation and road use, the high-temperature stability and low-temperature crack resistance of the asphalt binder for the seamless expansion joint are particularly important. In this study, a temperature scanning test, high-temperature creep test, and low-temperature stress relaxation test of Matrix 502 and Colas, as the asphalt binders in the seamless expansion joints of bridges, were performed before and after ageing using a dynamic shear rheometer. An analysis of the test results revealed that both asphalts had an outstanding stress-relaxation ability and resistance to high-temperature deformation. The maximum stress relaxation of modified asphalt coals with good performance was 83%, and the permanent deformation after short-term ageing was only 0.48%. Additionally, the technical indicators according to the Swiss Federal Road Office for seamless expansion joint road guidelines and the United States Strategic Highway Research Program applicable to the asphalt binder used in the seamless expansion joint of bridges were examined with focus on the development of cost-effective bituminous mixtures for seamless expansion joints.
{"title":"Study on rheological properties of asphalt binders for seamless expansion joints of bridges","authors":"P. Lu, Chenhao Zhou, Simin Huang, Dengguo Li","doi":"10.1080/13287982.2020.1862973","DOIUrl":"https://doi.org/10.1080/13287982.2020.1862973","url":null,"abstract":"ABSTRACT The seamless expansion joint has received considerable attention as a new type of bridge expansion joint owing to its good integrity and driving comfort. To satisfy the requirements of both deformation and road use, the high-temperature stability and low-temperature crack resistance of the asphalt binder for the seamless expansion joint are particularly important. In this study, a temperature scanning test, high-temperature creep test, and low-temperature stress relaxation test of Matrix 502 and Colas, as the asphalt binders in the seamless expansion joints of bridges, were performed before and after ageing using a dynamic shear rheometer. An analysis of the test results revealed that both asphalts had an outstanding stress-relaxation ability and resistance to high-temperature deformation. The maximum stress relaxation of modified asphalt coals with good performance was 83%, and the permanent deformation after short-term ageing was only 0.48%. Additionally, the technical indicators according to the Swiss Federal Road Office for seamless expansion joint road guidelines and the United States Strategic Highway Research Program applicable to the asphalt binder used in the seamless expansion joint of bridges were examined with focus on the development of cost-effective bituminous mixtures for seamless expansion joints.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"31 1","pages":"10 - 18"},"PeriodicalIF":1.1,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78933303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-26DOI: 10.1080/13287982.2020.1862968
Amauri da Silva Ribas Junior, J. C. Molina
ABSTRACT The county of Itapeva – SP, Brazil, has a great territorial extension, with many vicinal roads and, consequently, many wooden bridges with some type of problem. This research had the purpose of analysing 34 wooden bridges, with decks formed by natural longitudinal beams connected to the sawn transverse boards, to identify the main problems presented and proposition of solutions. The great majority of the analysed bridges (82.35%) presented a small span (up to 15 m), and the analysed spans ranged from 5 m to 44 m approximately. The lack of of preservative treatment was a problem for all analyzed bridges and this is a great factor that contributes to the reduction of the lifetime of the bridges. As a result of this work, the main construction and calculation recommendations for wooden bridges are presented. Two pre-sizing tables are also presented to guide builders and other interested parties in the construction of wooden bridges, in order to obtain secure structures, low cost and with guaranteed durability.
{"title":"Wooden bridges with deck of sawn board and round beams: main orientations","authors":"Amauri da Silva Ribas Junior, J. C. Molina","doi":"10.1080/13287982.2020.1862968","DOIUrl":"https://doi.org/10.1080/13287982.2020.1862968","url":null,"abstract":"ABSTRACT The county of Itapeva – SP, Brazil, has a great territorial extension, with many vicinal roads and, consequently, many wooden bridges with some type of problem. This research had the purpose of analysing 34 wooden bridges, with decks formed by natural longitudinal beams connected to the sawn transverse boards, to identify the main problems presented and proposition of solutions. The great majority of the analysed bridges (82.35%) presented a small span (up to 15 m), and the analysed spans ranged from 5 m to 44 m approximately. The lack of of preservative treatment was a problem for all analyzed bridges and this is a great factor that contributes to the reduction of the lifetime of the bridges. As a result of this work, the main construction and calculation recommendations for wooden bridges are presented. Two pre-sizing tables are also presented to guide builders and other interested parties in the construction of wooden bridges, in order to obtain secure structures, low cost and with guaranteed durability.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"35 1","pages":"1 - 9"},"PeriodicalIF":1.1,"publicationDate":"2020-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88542668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/13287982.2020.1835157
H. Tsang, John L. Wilson, E. Gad
ABSTRACT Collapse prevention is the primary objective of earthquake-resistant design of structures; hence, the probability of collapse should be taken as a crucial performance indicator for risk-based design of new structures or assessment of existing structures. One major challenge in collapse risk assessment is to reliably model the non-linear structural response behaviour. This study features the rocking response behaviour of precast reinforced concrete (RC) columns based on results from previous field testing on parts of a real building and supplemented with a study of their rocking behaviours through a series of shake-table tests. The effects of bidirectional earthquake actions on failure drift capacity of columns have also been incorporated, such that realistic estimates of displacement capacity were made for constructing collapse fragility functions, which were then combined with the ground motion recurrence relationships of Melbourne, Australia for the computation of collapse probability. A suite of typical soft-storey buildings was adopted, with considerations given to a diversity of site conditions. Deaggregation of the results reveals the range of return periods that controls the collapse risk, which could have important implications for the choice of earthquake scenarios for seismic analysis and design in regions of lower seismicity.
{"title":"Collapse probability of soft-storey building in Australia and implications for risk-based seismic design","authors":"H. Tsang, John L. Wilson, E. Gad","doi":"10.1080/13287982.2020.1835157","DOIUrl":"https://doi.org/10.1080/13287982.2020.1835157","url":null,"abstract":"ABSTRACT Collapse prevention is the primary objective of earthquake-resistant design of structures; hence, the probability of collapse should be taken as a crucial performance indicator for risk-based design of new structures or assessment of existing structures. One major challenge in collapse risk assessment is to reliably model the non-linear structural response behaviour. This study features the rocking response behaviour of precast reinforced concrete (RC) columns based on results from previous field testing on parts of a real building and supplemented with a study of their rocking behaviours through a series of shake-table tests. The effects of bidirectional earthquake actions on failure drift capacity of columns have also been incorporated, such that realistic estimates of displacement capacity were made for constructing collapse fragility functions, which were then combined with the ground motion recurrence relationships of Melbourne, Australia for the computation of collapse probability. A suite of typical soft-storey buildings was adopted, with considerations given to a diversity of site conditions. Deaggregation of the results reveals the range of return periods that controls the collapse risk, which could have important implications for the choice of earthquake scenarios for seismic analysis and design in regions of lower seismicity.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"95 1","pages":"307 - 319"},"PeriodicalIF":1.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74174929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/13287982.2020.1842581
S. M. Anas, M. I. Ansari, M. Alam
ABSTRACT In general, the blast-induced ground shock excites the foundation of the structure prior to the air-blast pressure because of the obvious reasons of difference in wave propagation velocities. However, the ground shock and air-blast pressure might act simultaneously on the structure for some standoff distance with a particular quantity of the explosive charge and cause severe damage than by air-blast pressure. Therefore, the ground shock and air-blast pressure both should be considered for estimating the structural response by such a near-field detonation. The objective of the present study is to assess the performance of the masonry heritage building under air-blast pressure without and with ground shock generated from on the ground spherical-shaped TNT explosive charge at varying standoff distances. The considered building is a heritage brick masonry structure in lime-surkhi mortar. The time lag between the ground shock and air-blast pressure for different scaled distances is evaluated. Stresses have been computed and are compared with the provisions of the Indian and Australian Standard Codes of Practice for Structural Use of Unreinforced Masonry. Also, the damage assessment has been carried out using the concrete-damaged plasticity (CDP) model available in the ABAQUS finite element program.
{"title":"Performance of masonry heritage building under air-blast pressure without and with ground shock","authors":"S. M. Anas, M. I. Ansari, M. Alam","doi":"10.1080/13287982.2020.1842581","DOIUrl":"https://doi.org/10.1080/13287982.2020.1842581","url":null,"abstract":"ABSTRACT In general, the blast-induced ground shock excites the foundation of the structure prior to the air-blast pressure because of the obvious reasons of difference in wave propagation velocities. However, the ground shock and air-blast pressure might act simultaneously on the structure for some standoff distance with a particular quantity of the explosive charge and cause severe damage than by air-blast pressure. Therefore, the ground shock and air-blast pressure both should be considered for estimating the structural response by such a near-field detonation. The objective of the present study is to assess the performance of the masonry heritage building under air-blast pressure without and with ground shock generated from on the ground spherical-shaped TNT explosive charge at varying standoff distances. The considered building is a heritage brick masonry structure in lime-surkhi mortar. The time lag between the ground shock and air-blast pressure for different scaled distances is evaluated. Stresses have been computed and are compared with the provisions of the Indian and Australian Standard Codes of Practice for Structural Use of Unreinforced Masonry. Also, the damage assessment has been carried out using the concrete-damaged plasticity (CDP) model available in the ABAQUS finite element program.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"4 1","pages":"329 - 344"},"PeriodicalIF":1.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78900170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/13287982.2020.1840012
M. Mahmoodian, A. Seyfallahi Asl, C. Q. Li
ABSTRACT An accurate structural assessment of rails under combined effect of fatigue and corrosion prevents a phenomenal disaster, also saves millions of dollars and people’s lives. Recent studies which are proposed to simulate a precise model fail to take into account the different underlying mechanism for rail corrosion. The current study presents a numerical procedure to investigate crack initiation under combined effect of fatigue and corrosion. A three-dimensional (3D) finite element model (FEM) which accounts for rolling contact stresses due to wheel-rail contact loads is developed. Then, stress distribution is used in a MATLAB code to estimate the fatigue crack initiation life. The advantage of the proposed model is considering the combined effect of rolling contact fatigue and corrosion on structural integrity of rails. This model is applied to a case study of rail assessment in Melbourne, Australia. The cracks orientations and locations which were based on the FEM results were in good agreement with the field observations.
{"title":"Combined effect of rolling contact fatigue and corrosion on structural performance of rails","authors":"M. Mahmoodian, A. Seyfallahi Asl, C. Q. Li","doi":"10.1080/13287982.2020.1840012","DOIUrl":"https://doi.org/10.1080/13287982.2020.1840012","url":null,"abstract":"ABSTRACT An accurate structural assessment of rails under combined effect of fatigue and corrosion prevents a phenomenal disaster, also saves millions of dollars and people’s lives. Recent studies which are proposed to simulate a precise model fail to take into account the different underlying mechanism for rail corrosion. The current study presents a numerical procedure to investigate crack initiation under combined effect of fatigue and corrosion. A three-dimensional (3D) finite element model (FEM) which accounts for rolling contact stresses due to wheel-rail contact loads is developed. Then, stress distribution is used in a MATLAB code to estimate the fatigue crack initiation life. The advantage of the proposed model is considering the combined effect of rolling contact fatigue and corrosion on structural integrity of rails. This model is applied to a case study of rail assessment in Melbourne, Australia. The cracks orientations and locations which were based on the FEM results were in good agreement with the field observations.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"5 1","pages":"320 - 328"},"PeriodicalIF":1.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84131205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-25DOI: 10.1080/13287982.2020.1809811
Danda Li, Jianzhuang Xiao, Y. Zhuge, J. Mills, H. Senko, Xing Ma
ABSTRACT This paper addresses the structural performance of crumb rubberised concrete (CRC) and reinforced CRC slabs under static and low-velocity impact loads. An innovated setup was designed to investigate the impact of behaviour of concrete material based on the drop-weight test. The drop-weight velocities before and after impact were recorded through a laser system. Based on the velocity variation, the energy that was absorbed in concrete material during the test, which also was the impact resistance of the sample’s failure section, had been calculated. CRC samples with rubber percentages varying from 0% to 20% were tested. Experimental results verified the advantages of using rubber on material impact behaviour. Finally, as a structural application, reinforced CRC slabs were tested under static and impact loads. Experimental results showed that CRC slabs exhibited superior post-cracking performance with member moment capacities comparable or even higher than that of reinforced traditional concrete (TC) slabs. It is believed that this unique phenomenon was due to zip-shaped cracking section along CRC slab width. At last, a series of impact tests were conducted and test results showed a significant reduction in the peak stress response in CRC slabs when compared with TC slabs.
{"title":"Experimental study on crumb rubberised concrete (CRC) and reinforced CRC slabs under static and impact loads","authors":"Danda Li, Jianzhuang Xiao, Y. Zhuge, J. Mills, H. Senko, Xing Ma","doi":"10.1080/13287982.2020.1809811","DOIUrl":"https://doi.org/10.1080/13287982.2020.1809811","url":null,"abstract":"ABSTRACT This paper addresses the structural performance of crumb rubberised concrete (CRC) and reinforced CRC slabs under static and low-velocity impact loads. An innovated setup was designed to investigate the impact of behaviour of concrete material based on the drop-weight test. The drop-weight velocities before and after impact were recorded through a laser system. Based on the velocity variation, the energy that was absorbed in concrete material during the test, which also was the impact resistance of the sample’s failure section, had been calculated. CRC samples with rubber percentages varying from 0% to 20% were tested. Experimental results verified the advantages of using rubber on material impact behaviour. Finally, as a structural application, reinforced CRC slabs were tested under static and impact loads. Experimental results showed that CRC slabs exhibited superior post-cracking performance with member moment capacities comparable or even higher than that of reinforced traditional concrete (TC) slabs. It is believed that this unique phenomenon was due to zip-shaped cracking section along CRC slab width. At last, a series of impact tests were conducted and test results showed a significant reduction in the peak stress response in CRC slabs when compared with TC slabs.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"440 1","pages":"294 - 306"},"PeriodicalIF":1.1,"publicationDate":"2020-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74398619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-27DOI: 10.1080/13287982.2020.1796075
Qingming Xiang, Xuansheng Cheng, Jiaxuan Su, Liang Ma
ABSTRACT In this paper, grouting compactness and load forms are taken as control conditions, and the bending behaviour of 8 PCBs (prestressed concrete beams) with metal bellows of different grouting compactness is experimentally examined. The strain and deflection of the prestressed beams are measured, and the failure process and failure modes are investigated under the action of different load forms. The rebar strain, bending bearing capacity and bending stiffness of the PCBs are explored, and a comparative analysis is conducted. The results show that the average strain is linearly distributed along the beam height for all PCBs. The load versus span deflection curve and rebar strain curve of the specimens show that the grouting compactness has little effect on the early stage of beam cracking, but the effect becomes increasingly obvious after the beam cracks. Under different load forms, when the grouting compactness of the PCB increases, the crack distribution becomes more concentrated, the spacing narrows, and the ductility decreases. The load-bearing capacity of the PCB with 100% grouting compactness can be improved by more than 30% compared with that of the prestressed beam with 0% grouting compactness of the metal bellows.
{"title":"Bending behaviour experiment of a prestressed concrete beam with metal bellows","authors":"Qingming Xiang, Xuansheng Cheng, Jiaxuan Su, Liang Ma","doi":"10.1080/13287982.2020.1796075","DOIUrl":"https://doi.org/10.1080/13287982.2020.1796075","url":null,"abstract":"ABSTRACT In this paper, grouting compactness and load forms are taken as control conditions, and the bending behaviour of 8 PCBs (prestressed concrete beams) with metal bellows of different grouting compactness is experimentally examined. The strain and deflection of the prestressed beams are measured, and the failure process and failure modes are investigated under the action of different load forms. The rebar strain, bending bearing capacity and bending stiffness of the PCBs are explored, and a comparative analysis is conducted. The results show that the average strain is linearly distributed along the beam height for all PCBs. The load versus span deflection curve and rebar strain curve of the specimens show that the grouting compactness has little effect on the early stage of beam cracking, but the effect becomes increasingly obvious after the beam cracks. Under different load forms, when the grouting compactness of the PCB increases, the crack distribution becomes more concentrated, the spacing narrows, and the ductility decreases. The load-bearing capacity of the PCB with 100% grouting compactness can be improved by more than 30% compared with that of the prestressed beam with 0% grouting compactness of the metal bellows.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"133 1","pages":"279 - 293"},"PeriodicalIF":1.1,"publicationDate":"2020-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78464700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/13287982.2020.1783068
Ian W Hooley, S. Al-Deen
ABSTRACT The design of cantilever retaining walls is a routine task for the civil or structural engineer, but the design ultimately adopted typically results in highly varying vertical foundation pressure across the base. This variation in foundation pressure promotes differential settlement, thus increasing the tilting tendency of the whole retaining wall over time. This paper demonstrates that there are generally two (alternative) positions for the stem on the base for which there will be no tendency for the wall to tilt either forwards or backwards under the action of given loadings, and develops a direct approach for the determination of these positions with a view to minimising the ultimate tilting tendency of the wall.
{"title":"Design of cantilever retaining walls for minimum tilting tendency","authors":"Ian W Hooley, S. Al-Deen","doi":"10.1080/13287982.2020.1783068","DOIUrl":"https://doi.org/10.1080/13287982.2020.1783068","url":null,"abstract":"ABSTRACT The design of cantilever retaining walls is a routine task for the civil or structural engineer, but the design ultimately adopted typically results in highly varying vertical foundation pressure across the base. This variation in foundation pressure promotes differential settlement, thus increasing the tilting tendency of the whole retaining wall over time. This paper demonstrates that there are generally two (alternative) positions for the stem on the base for which there will be no tendency for the wall to tilt either forwards or backwards under the action of given loadings, and develops a direct approach for the determination of these positions with a view to minimising the ultimate tilting tendency of the wall.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"70 1","pages":"254 - 262"},"PeriodicalIF":1.1,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88096975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1080/13287982.2020.1786988
M. Haddad, N. Shrive
ABSTRACT Concentrically braced steel frames (CBFs) are often used in buildings to resist lateral loads induced by wind and seismic excitations. Large-size wide-flange (WF) steel brace members could be selected and used in these frames. In the current study, a finite element model (FEM) with a strain-based fracture rule is presented to investigate the performance of a large-size WF brace member in single-storey CBF with different sizes of beams and columns when subjected to reversed axial displacements. The effects of restraining the far ends of the beam bottom-flange, increasing the thickness of tab-plates, increasing the number of bolts used to connect the tab-plates to the web of the beam, and the location of the work-point along the brace with respect the beam-column assembly, on the hysteresis response of the frame are investigated. Results suggest that it may be advantageous to reduce the number of bolts and to increase the bolt size to allow for an increase in the thickness of the tab-plates to resist the extreme rotational demand in high seismic regions, thereby preventing fracture of the weld between the tab-plates and the column flange.
{"title":"Cyclic performance and fracture of wide flanged concentrically steel braced frames","authors":"M. Haddad, N. Shrive","doi":"10.1080/13287982.2020.1786988","DOIUrl":"https://doi.org/10.1080/13287982.2020.1786988","url":null,"abstract":"ABSTRACT Concentrically braced steel frames (CBFs) are often used in buildings to resist lateral loads induced by wind and seismic excitations. Large-size wide-flange (WF) steel brace members could be selected and used in these frames. In the current study, a finite element model (FEM) with a strain-based fracture rule is presented to investigate the performance of a large-size WF brace member in single-storey CBF with different sizes of beams and columns when subjected to reversed axial displacements. The effects of restraining the far ends of the beam bottom-flange, increasing the thickness of tab-plates, increasing the number of bolts used to connect the tab-plates to the web of the beam, and the location of the work-point along the brace with respect the beam-column assembly, on the hysteresis response of the frame are investigated. Results suggest that it may be advantageous to reduce the number of bolts and to increase the bolt size to allow for an increase in the thickness of the tab-plates to resist the extreme rotational demand in high seismic regions, thereby preventing fracture of the weld between the tab-plates and the column flange.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":"59 1","pages":"263 - 278"},"PeriodicalIF":1.1,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85523026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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