Pub Date : 2022-10-02DOI: 10.1080/13287982.2022.2049072
C. Rengifo, Diego A. Bravo
ABSTRACT In this study, we propose to evaluate structural control systems in terms of mechanical impedance and the peak of energy stored by the structure. Our main hypothesis is that the higher the mechanical impedance, the lower the peak of energy reached by the structure. This peak is calculated as the maximum of the difference between the energy injected by the seism and the energy dissipated as heat by viscous dampers. To support our claim, we performed numerical simulations on a three-story planar building comprising 12 revolute and four prismatic joints. Instead of using a linear mass-spring-damper model, we simulated a set of nonlinear equations given by the Newton-Euler (NE) algorithm, which has been widely used in robotics, but rarely in structural control. For energy dissipation, we compared a proportional derivative (PD) with a computed torque control (CTC). Simulation results for the CTC indicate that when all parameters of the structure are perfectly known, the deviations of the revolute and prismatic joints with respect to their nominal values are close to zero. This feature leads to almost null energy dissipation, but also reduces the energy transferred by the seism to the structure.
{"title":"Modeling and structural control of a building with holonomic constraints","authors":"C. Rengifo, Diego A. Bravo","doi":"10.1080/13287982.2022.2049072","DOIUrl":"https://doi.org/10.1080/13287982.2022.2049072","url":null,"abstract":"ABSTRACT In this study, we propose to evaluate structural control systems in terms of mechanical impedance and the peak of energy stored by the structure. Our main hypothesis is that the higher the mechanical impedance, the lower the peak of energy reached by the structure. This peak is calculated as the maximum of the difference between the energy injected by the seism and the energy dissipated as heat by viscous dampers. To support our claim, we performed numerical simulations on a three-story planar building comprising 12 revolute and four prismatic joints. Instead of using a linear mass-spring-damper model, we simulated a set of nonlinear equations given by the Newton-Euler (NE) algorithm, which has been widely used in robotics, but rarely in structural control. For energy dissipation, we compared a proportional derivative (PD) with a computed torque control (CTC). Simulation results for the CTC indicate that when all parameters of the structure are perfectly known, the deviations of the revolute and prismatic joints with respect to their nominal values are close to zero. This feature leads to almost null energy dissipation, but also reduces the energy transferred by the seism to the structure.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88358011","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 : 2022-10-02DOI: 10.1080/13287982.2022.2091092
H. Wijaya, P. Rajeev, R. Kalfat, E. Gad, K. Abdouka
ABSTRACT Ageing infrastructure is becoming an increasing challenge as a result of deterioration and greater loading demands. Modern cities were built on top of complex underground infrastructure networks many of which are still in-service beyond their design life. The safety assessment of underground structures is of utmost importance to avoid catastrophic failures and develop cost-effective renewal and rehabilitation strategies. However, the lack of design documentation and absence of data on the level of structural deterioration make determination of current structural capacity a challenge. This paper presents a probabilistic based assessment framework for underground utility service pits using Bayesian updating technique, which is used to refine the probabilistic distribution of material properties from the prior distribution constructed using published data. A case study of an underground pit located in Central Melbourne is provided. Extensive experimental testing was conducted to characterise the material properties and a full-scale masonry wall was tested to understand the failure mode due to earth pressure and traffic load. The test data was used in strength prediction models to achieve a more accurate estimate for wall capacity. Further, the strength degradation models were integrated to develop the time-dependent material models, which were eventually used to compute reliability index.
{"title":"Structural assessment of underground utility services pit using Bayesian inference","authors":"H. Wijaya, P. Rajeev, R. Kalfat, E. Gad, K. Abdouka","doi":"10.1080/13287982.2022.2091092","DOIUrl":"https://doi.org/10.1080/13287982.2022.2091092","url":null,"abstract":"ABSTRACT Ageing infrastructure is becoming an increasing challenge as a result of deterioration and greater loading demands. Modern cities were built on top of complex underground infrastructure networks many of which are still in-service beyond their design life. The safety assessment of underground structures is of utmost importance to avoid catastrophic failures and develop cost-effective renewal and rehabilitation strategies. However, the lack of design documentation and absence of data on the level of structural deterioration make determination of current structural capacity a challenge. This paper presents a probabilistic based assessment framework for underground utility service pits using Bayesian updating technique, which is used to refine the probabilistic distribution of material properties from the prior distribution constructed using published data. A case study of an underground pit located in Central Melbourne is provided. Extensive experimental testing was conducted to characterise the material properties and a full-scale masonry wall was tested to understand the failure mode due to earth pressure and traffic load. The test data was used in strength prediction models to achieve a more accurate estimate for wall capacity. Further, the strength degradation models were integrated to develop the time-dependent material models, which were eventually used to compute reliability index.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76287987","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 : 2022-09-08DOI: 10.1080/13287982.2022.2120239
S. Karimi, O. Mirza
ABSTRACT Bridges are integral parts of the infrastructure and play a major role in civil engineering. Bridge health monitoring is necessary to extend the life of a bridge and retain safety. Periodic monitoring contributes significantly in keeping these structures operational and extends structural integrity. Different researchers have proposed different methods for identifying bridge damages based on different theories and laboratory tests. Several review papers have been published in the literature on the identification of damage and crack in bridge structures in the last few decades. In this paper, a review of literature on damage identification in bridge structures based on different methods and theories is carried out. The aim of this paper is to critically evaluate different methods that have been proposed to detect damages in different bridges. Different papers have been carefully reviewed, and the gaps, limitations, and superiority of the methods used are identified. Furthermore, in most of the reviews, future applications and several sustainable methods which are necessary for bridge monitoring are covered. This study significantly contributes to the literature by critically examining different methods, giving guidelines on the methods that identify the damages in bridge structures more accurately, and serving as a good reference for other researchers and future works.
{"title":"Damage identification in bridge structures: review of available methods and case studies","authors":"S. Karimi, O. Mirza","doi":"10.1080/13287982.2022.2120239","DOIUrl":"https://doi.org/10.1080/13287982.2022.2120239","url":null,"abstract":"ABSTRACT Bridges are integral parts of the infrastructure and play a major role in civil engineering. Bridge health monitoring is necessary to extend the life of a bridge and retain safety. Periodic monitoring contributes significantly in keeping these structures operational and extends structural integrity. Different researchers have proposed different methods for identifying bridge damages based on different theories and laboratory tests. Several review papers have been published in the literature on the identification of damage and crack in bridge structures in the last few decades. In this paper, a review of literature on damage identification in bridge structures based on different methods and theories is carried out. The aim of this paper is to critically evaluate different methods that have been proposed to detect damages in different bridges. Different papers have been carefully reviewed, and the gaps, limitations, and superiority of the methods used are identified. Furthermore, in most of the reviews, future applications and several sustainable methods which are necessary for bridge monitoring are covered. This study significantly contributes to the literature by critically examining different methods, giving guidelines on the methods that identify the damages in bridge structures more accurately, and serving as a good reference for other researchers and future works.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80765478","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 : 2022-08-28DOI: 10.1080/13287982.2022.2117319
S. Morkhade, L. Gupta
ABSTRACT In this study, experimental and numerical approaches are adopted to comprehensively investigate the flexural strength capacity and failure modes of I-shaped steel members with various web openings geometry. To validate the results, the finite element models are established using ABAQUS with the same configurations as the test specimens. Based on the experimental and numerical investigation it is observed that, the web openings not only weaken the practical section but also destroy its continuity. The common mode of failure observed in beams with web openings is excessive bending, Vierendeel mechanism and web post buckling. When the opening ratio exceeds 0.75, the openings greatly affect the stability of the components, which results in reduction in strength capacity of perforated beams. In contrast, when the opening ratio is less than 0.5, the openings have negligible impact on the stability and strength component. The web openings also have a significant impact on the bearing strength of the members when the provided web post width is less than 200 mm. In contrast, when the web post width exceeded 200 mm, the web opening ratio had only a small effect on the member bearing capacity. The response of the perforated beams was presented in terms of load-deflection and moment-deflection curves. .
{"title":"Critical study of steel beams with web openings","authors":"S. Morkhade, L. Gupta","doi":"10.1080/13287982.2022.2117319","DOIUrl":"https://doi.org/10.1080/13287982.2022.2117319","url":null,"abstract":"ABSTRACT In this study, experimental and numerical approaches are adopted to comprehensively investigate the flexural strength capacity and failure modes of I-shaped steel members with various web openings geometry. To validate the results, the finite element models are established using ABAQUS with the same configurations as the test specimens. Based on the experimental and numerical investigation it is observed that, the web openings not only weaken the practical section but also destroy its continuity. The common mode of failure observed in beams with web openings is excessive bending, Vierendeel mechanism and web post buckling. When the opening ratio exceeds 0.75, the openings greatly affect the stability of the components, which results in reduction in strength capacity of perforated beams. In contrast, when the opening ratio is less than 0.5, the openings have negligible impact on the stability and strength component. The web openings also have a significant impact on the bearing strength of the members when the provided web post width is less than 200 mm. In contrast, when the web post width exceeded 200 mm, the web opening ratio had only a small effect on the member bearing capacity. The response of the perforated beams was presented in terms of load-deflection and moment-deflection curves. .","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88902913","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 : 2022-08-24DOI: 10.1080/13287982.2022.2112286
N. Khattak, H. Derakhshan, D. Thambiratnam, N. Perera, J. Ingham
ABSTRACT Worldwide, unreinforced masonry (URM) buildings are present in abundance with many holding cultural and heritage value. URM buildings have a known history of poor performance during past earthquakes because of the weak tensile properties and lack of mechanical connections between elements. Information about the construction of URM buildings for a region is important because it can help engineers and policy makers to perform seismic assessment, risk and loss studies. In this regard, this study includes a characterisation of the heritage URM buildings in Brisbane City, Australia, and its surrounding suburbs using the Queensland Heritage Register (QHR). The QHR includes a total of 1775 heritage sites, of which 323 are identified as URM buildings in Brisbane City and surrounding suburbs. The studied building characteristics obtained from QHR included the architectural styles, construction year, function/use, number of storeys, roof material and load-bearing wall materials. Other features such as roof types (shapes), plan geometry, isolated or interconnected buildings, verandas and openings, and finally the presence of seismic hazards such as gable-end walls, chimneys, and parapets have been obtained using online 3D maps. It was concluded that heritage registers in combination with online digital resources can be successfully utilised to characterise URM buildings.
{"title":"Using heritage building registers to characterise unreinforced masonry buildings of Brisbane, Australia","authors":"N. Khattak, H. Derakhshan, D. Thambiratnam, N. Perera, J. Ingham","doi":"10.1080/13287982.2022.2112286","DOIUrl":"https://doi.org/10.1080/13287982.2022.2112286","url":null,"abstract":"ABSTRACT Worldwide, unreinforced masonry (URM) buildings are present in abundance with many holding cultural and heritage value. URM buildings have a known history of poor performance during past earthquakes because of the weak tensile properties and lack of mechanical connections between elements. Information about the construction of URM buildings for a region is important because it can help engineers and policy makers to perform seismic assessment, risk and loss studies. In this regard, this study includes a characterisation of the heritage URM buildings in Brisbane City, Australia, and its surrounding suburbs using the Queensland Heritage Register (QHR). The QHR includes a total of 1775 heritage sites, of which 323 are identified as URM buildings in Brisbane City and surrounding suburbs. The studied building characteristics obtained from QHR included the architectural styles, construction year, function/use, number of storeys, roof material and load-bearing wall materials. Other features such as roof types (shapes), plan geometry, isolated or interconnected buildings, verandas and openings, and finally the presence of seismic hazards such as gable-end walls, chimneys, and parapets have been obtained using online 3D maps. It was concluded that heritage registers in combination with online digital resources can be successfully utilised to characterise URM buildings.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73518623","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 : 2022-07-08DOI: 10.1080/13287982.2022.2098600
F. S. Klak, H. Saleh, Abdulla S. Tais
ABSTRACT This paper presents the results of a testing program to examine the possibility of using crushed clay bricks as fine aggregate in concrete and mortar mixtures. A total of 90 specimens of concrete and mortar were cast at different percentages of crushed bricks (0, 25, 50, 75, and 100)% by weight as replacement of fine aggregate. Mechanical and physical properties of the specimens were conducted and presented in this paper. The experimental results indicated a decrease in compressive strength and splitting tensile strength of the concrete specimens. Also, the presence of crushed bricks aggregate in mixtures reduces the workability and flow ratio compared to the reference mix due to high water demand of the recycled aggregates than the normal aggregate. It can be noted that crushed bricks concrete is a convenient replacement in treading and finishing areas in buildings and in high floors in order to reduce the dead loads.
{"title":"Recycling of crushed clay bricks as fine aggregate in concrete and cement mortar","authors":"F. S. Klak, H. Saleh, Abdulla S. Tais","doi":"10.1080/13287982.2022.2098600","DOIUrl":"https://doi.org/10.1080/13287982.2022.2098600","url":null,"abstract":"ABSTRACT This paper presents the results of a testing program to examine the possibility of using crushed clay bricks as fine aggregate in concrete and mortar mixtures. A total of 90 specimens of concrete and mortar were cast at different percentages of crushed bricks (0, 25, 50, 75, and 100)% by weight as replacement of fine aggregate. Mechanical and physical properties of the specimens were conducted and presented in this paper. The experimental results indicated a decrease in compressive strength and splitting tensile strength of the concrete specimens. Also, the presence of crushed bricks aggregate in mixtures reduces the workability and flow ratio compared to the reference mix due to high water demand of the recycled aggregates than the normal aggregate. It can be noted that crushed bricks concrete is a convenient replacement in treading and finishing areas in buildings and in high floors in order to reduce the dead loads.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80626792","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 : 2022-07-04DOI: 10.1080/13287982.2022.2093006
Mohamed Amine Abid, A. El Ghoulbzouri, L. Ikharrazne
ABSTRACT Progressive collapse is the failure of primary structural components produced by natural or abnormal events that may result in a total or partial collapse of the structure. In this paper, several structure models, under different column removal scenarios, were modeled and analyzed using the FE program SAP2000 to evaluate the effect of span length, the strength of structural members, and cross-section on the steel building’s resistance against progressive collapse. The Alternative Load Path method was carried out using the linear static and nonlinear dynamic analysis following the GSA 2003 guidelines for this investigation. The material and the geometric nonlinearities must be considered in the nonlinear dynamic analysis. The contribution of span length, steel grade, and cross-section to the response of the structural system was studied through the Demand Capacity Ratio for the linear static analysis. The variation of several parameters, such as bending moments, plastic hinges status and their rotations, displacements, and ductility, was discussed based on the response of the nonlinear dynamic analysis. The main objective of this study is to demonstrate the impact of the latter parameters on the structural enhancement and the reduction of the damage level triggered by the failure of a primary structural component.
{"title":"FE modelling progressive collapse assessment of steel moment frames-parametric study","authors":"Mohamed Amine Abid, A. El Ghoulbzouri, L. Ikharrazne","doi":"10.1080/13287982.2022.2093006","DOIUrl":"https://doi.org/10.1080/13287982.2022.2093006","url":null,"abstract":"ABSTRACT Progressive collapse is the failure of primary structural components produced by natural or abnormal events that may result in a total or partial collapse of the structure. In this paper, several structure models, under different column removal scenarios, were modeled and analyzed using the FE program SAP2000 to evaluate the effect of span length, the strength of structural members, and cross-section on the steel building’s resistance against progressive collapse. The Alternative Load Path method was carried out using the linear static and nonlinear dynamic analysis following the GSA 2003 guidelines for this investigation. The material and the geometric nonlinearities must be considered in the nonlinear dynamic analysis. The contribution of span length, steel grade, and cross-section to the response of the structural system was studied through the Demand Capacity Ratio for the linear static analysis. The variation of several parameters, such as bending moments, plastic hinges status and their rotations, displacements, and ductility, was discussed based on the response of the nonlinear dynamic analysis. The main objective of this study is to demonstrate the impact of the latter parameters on the structural enhancement and the reduction of the damage level triggered by the failure of a primary structural component.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89859315","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 : 2022-06-27DOI: 10.1080/13287982.2022.2092949
M. Wasim, Osmar Oliveira
ABSTRACT Volumetric steel structures are commonly used in the construction of modular buildings to overcome environmental hazards, control wastage, minimise construction safety issues, improve productivity and cost-effectiveness, reduce labour, and execute quick project completion. An adequate structural design and effective manufacturing are both integral processes to produce efficient and durable volumetric steel structures. Design for Manufacture and Assembly (DfMA) principles known for efficient design in the automobile industry can significantly improve the design of volumetric steel structures in terms of overall cost, safety, sustainability, productivity and time. The current research presents a case study of a volumetric steel structure in which structural design and DfMA approaches were integrated, and 3D visualisation was achieved by Building Information Model (BIM) and Solidworks that has limited previous research. The findings of this research reveal sustainable, material and cost optimised design for the prefabricated 3D steel structures. Furthermore, the novelty of the current research is enhanced by proposing a model for the automated efficient design and production of volumetric steel structures.
{"title":"Efficient design of a prefabricated steel structure integrating design for manufacture and assembly concepts","authors":"M. Wasim, Osmar Oliveira","doi":"10.1080/13287982.2022.2092949","DOIUrl":"https://doi.org/10.1080/13287982.2022.2092949","url":null,"abstract":"ABSTRACT Volumetric steel structures are commonly used in the construction of modular buildings to overcome environmental hazards, control wastage, minimise construction safety issues, improve productivity and cost-effectiveness, reduce labour, and execute quick project completion. An adequate structural design and effective manufacturing are both integral processes to produce efficient and durable volumetric steel structures. Design for Manufacture and Assembly (DfMA) principles known for efficient design in the automobile industry can significantly improve the design of volumetric steel structures in terms of overall cost, safety, sustainability, productivity and time. The current research presents a case study of a volumetric steel structure in which structural design and DfMA approaches were integrated, and 3D visualisation was achieved by Building Information Model (BIM) and Solidworks that has limited previous research. The findings of this research reveal sustainable, material and cost optimised design for the prefabricated 3D steel structures. Furthermore, the novelty of the current research is enhanced by proposing a model for the automated efficient design and production of volumetric steel structures.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76319851","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 : 2022-06-18DOI: 10.1080/13287982.2022.2088654
A. Jabbar, D. Mohammed, M. J. Hamood
ABSTRACT Transverse shear reinforcement is usually used to resist the induced shear stresses in conventional concrete beams. Ultra-high performance concrete (UHPC) with fibres has high strength, post-peak strength, and strain softening. Such features can impact the behavior of the beam under loading. This paper presents the results of experimental tests performed on simply supported UHPC T-beams with basalt or steel fibres, with or without stirrups, subjected to four-point bending loads. The volume fraction of basalt fibres, the shear span, and the presence of stirrups are adopted as parameters. The possibility of achieving equivalent performance by using basalt or steel fibres, as shear micro-reinforcement, instead of using traditional steel stirrups is discussed from viewpoint of the beam structural behavior due to shear stress. The results show that the shear resistance increases with increasing fibre content and decreases with increasing shear span. The addition of basalt or steel fibres alters the fracture from brittle to ductile. Also, it is possible to partially replace the stirrups by using 1.0 % or more steel fibres or 0.5-1.0 % basalt fibres in the UHPC matrix. However, it is preferable to use a considerable ratio of shear rebars to avoid the dominance of shear failure.
{"title":"Using Fibers instead of Stirrups for Shear in Ultra-High Performance Concrete T-beams","authors":"A. Jabbar, D. Mohammed, M. J. Hamood","doi":"10.1080/13287982.2022.2088654","DOIUrl":"https://doi.org/10.1080/13287982.2022.2088654","url":null,"abstract":"ABSTRACT Transverse shear reinforcement is usually used to resist the induced shear stresses in conventional concrete beams. Ultra-high performance concrete (UHPC) with fibres has high strength, post-peak strength, and strain softening. Such features can impact the behavior of the beam under loading. This paper presents the results of experimental tests performed on simply supported UHPC T-beams with basalt or steel fibres, with or without stirrups, subjected to four-point bending loads. The volume fraction of basalt fibres, the shear span, and the presence of stirrups are adopted as parameters. The possibility of achieving equivalent performance by using basalt or steel fibres, as shear micro-reinforcement, instead of using traditional steel stirrups is discussed from viewpoint of the beam structural behavior due to shear stress. The results show that the shear resistance increases with increasing fibre content and decreases with increasing shear span. The addition of basalt or steel fibres alters the fracture from brittle to ductile. Also, it is possible to partially replace the stirrups by using 1.0 % or more steel fibres or 0.5-1.0 % basalt fibres in the UHPC matrix. However, it is preferable to use a considerable ratio of shear rebars to avoid the dominance of shear failure.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77653453","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 : 2022-06-16DOI: 10.1080/13287982.2022.2088055
H. Mousavi, S. Sabbagh Yazdi, M. Almohammad-albakkar
ABSTRACT In this paper, a new method is presented for designing nonlinear viscous dampers to improve the seismic response of multi-storey frames with braces. In this regard, a 2/3-scale three-storey steel structure is used as a benchmark case. Considering the cylindrical friction damper equipment on the bracings, the optimum slip loads are calculated for cylindrical friction damper of all stories under selected earthquakes records. For three earthquakes in optimised slip loads, the force versus the difference between velocities of two ends of cylindrical friction dampers for all stories is combined and plotted according to the velocity range for all earthquakes. Finally, the velocity–force curve is fitted and used for finding the design parameter of nonlinear viscous dampers. Similarly, the aforementioned steps are applied for El-Centro with three scales (of 50, 100 and 200% El Centro). According to the analysis results, the viscous dampers which are designed by using this approach present better performance than that of cylindrical friction dampers and considerably reduce the structural response. The values of displacement, acceleration and base shear are reduced between 63–96%, 44–85% and 14–78%, respectively. Moreover, the results of viscous dampers designed using three and one earthquakes are very similar.
本文提出了一种设计非线性粘性阻尼器的新方法，以改善带支撑的多层框架的地震响应。在这方面，采用了一个2/3比例的三层钢结构作为基准案例。考虑支撑柱上的圆柱摩擦减振器装置，在选定的地震记录下，计算了各层圆柱摩擦减振器的最佳滑移荷载。对于优化滑动载荷下的三次地震，根据所有地震的速度范围，将所有楼层的力与圆柱形摩擦阻尼器两端的速度差进行组合并绘制。最后，对速度-力曲线进行拟合，求出非线性粘性阻尼器的设计参数。同样，上述步骤适用于El-Centro的三个尺度(50,100和200% El Centro)。分析结果表明，采用该方法设计的粘性阻尼器性能优于圆柱摩擦阻尼器，并能显著降低结构响应。位移、加速度和基底剪切值分别减小63-96%、44-85%和14-78%。此外，用三次地震和一次地震设计粘性阻尼器的结果非常相似。
{"title":"A novel method for efficient design of frame structures equipped with nonlinear viscous dampers by using computational results of cylindrical friction damper","authors":"H. Mousavi, S. Sabbagh Yazdi, M. Almohammad-albakkar","doi":"10.1080/13287982.2022.2088055","DOIUrl":"https://doi.org/10.1080/13287982.2022.2088055","url":null,"abstract":"ABSTRACT In this paper, a new method is presented for designing nonlinear viscous dampers to improve the seismic response of multi-storey frames with braces. In this regard, a 2/3-scale three-storey steel structure is used as a benchmark case. Considering the cylindrical friction damper equipment on the bracings, the optimum slip loads are calculated for cylindrical friction damper of all stories under selected earthquakes records. For three earthquakes in optimised slip loads, the force versus the difference between velocities of two ends of cylindrical friction dampers for all stories is combined and plotted according to the velocity range for all earthquakes. Finally, the velocity–force curve is fitted and used for finding the design parameter of nonlinear viscous dampers. Similarly, the aforementioned steps are applied for El-Centro with three scales (of 50, 100 and 200% El Centro). According to the analysis results, the viscous dampers which are designed by using this approach present better performance than that of cylindrical friction dampers and considerably reduce the structural response. The values of displacement, acceleration and base shear are reduced between 63–96%, 44–85% and 14–78%, respectively. Moreover, the results of viscous dampers designed using three and one earthquakes are very similar.","PeriodicalId":45617,"journal":{"name":"Australian Journal of Structural Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80369018","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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