To mitigate the challenges in managing the damage level of reinforced concrete(RC)pier columns subjected to cyclic reverse loading,this study conducted a series of cyclic reverse tests on RC pier columns.By analyzing ...To mitigate the challenges in managing the damage level of reinforced concrete(RC)pier columns subjected to cyclic reverse loading,this study conducted a series of cyclic reverse tests on RC pier columns.By analyzing the outcomes of destructive testing on various specimens and fine-tuning the results with the aid of the IMK(Ibarra Medina Krawinkler)recovery model,the energy dissipation capacity coefficient of the pier columns were able to be determined.Furthermore,utilizing the calibrated damage model parameters,the damage index for each specimen were calculated.Based on the obtained damage levels,three distinct pre-damage conditions were designed for the pier columns:minor damage,moderate damage,and severe damage.The study then predicted the variations in hysteresis curves and damage indices under cyclic loading conditions.The experimental findings reveal that the displacement at the top of the pier columns can serve as a reliable indicator for controlling the damage level of pier columns post-loading.Moreover,the calibrated damage index model exhibits proficiency in accurately predicting the damage level of RC pier columns under cyclic loading.展开更多
The structural behaviour of precast shear wall-diaphragm connection was compared with the monolithic connection under seismic loading.The monolithic connection was made by using U-bars connecting shear wall and slab,a...The structural behaviour of precast shear wall-diaphragm connection was compared with the monolithic connection under seismic loading.The monolithic connection was made by using U-bars connecting shear wall and slab,and the precast connection was made by using dowel bars in two steps.Firstly,U-shaped dowel bars from the precast shear wall lower panel and precast slab were connected by the longitudinal reinforcement,and screed concreting was done above the precast slab.Secondly,the shear wall upper panel was connected using the dowel bar protruding from the shear wall lower panel.The gap between the dowel bars and the duct was filled with non-shrink grout.The specimens were subjected to reverse cyclic loading at the ends of the slab.This study also aimed to develop a 3-D numerical model using ABAQUS software.The non-linear properties of concrete were defined by using the concrete damaged plasticity(CDP)model to analyse the response of the structure.The precast dowel connection between the shear wall and slab showed superior performance concerning ductility,strength,stiffness and energy dissipation.The developed finite element model exactly predicted the behaviour of connections as similar to that of experimental testing in the laboratory.The average difference between the results from finite element analysis and experimental testing was less than 20%.The results point to the conclusion that the shear resistance is provided by the dowel bars and the stiffness of the precast specimen is due to the diaphragm action of the precast slab.The damage parameter and the interaction between structural members play a crucial role in the modelling of precast connections.展开更多
The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductilit...The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductility design has not been rigorously enforced inmany developing countries that are prone to seismic risks.Numerous studies have evaluated the effectiveness of joint behavior based on both ductile and non-ductile designs under cyclic loading.Previous research has demonstrated that enhancing joint regions with Ultra-High Performance Steel Fiber Reinforced Concrete(UHPSFRC)significantly improves the seismic resistance of structural components.This paper presents a detailed analysis of the considerable improvements in energy dissipation capacity and stiffness degradation observed in both reinforced test samples compared to the control sample.Furthermore,assessing the effective performance of enhanced reinforced concrete joints is a critical parameter for evaluating the feasibility of this approach.The findings highlight the potential for UHPSFRC to enhance the resilience of concrete structures under seismic loads,providing a viable solution to improve the safety and durability of infrastructure in earthquake-prone regions.This study aims to inform future design methodologies and standards in seismic-resistant construction in developing nations,emphasizing the importance of adopting innovative materials to mitigate earthquake risks effectively.展开更多
The seismic performance of precast reinforced concrete （RC） coupled shear walls is significantly influenced by coupling beams and the beam-to-wall joints during large deformations into plastic ranges. This study inv...The seismic performance of precast reinforced concrete （RC） coupled shear walls is significantly influenced by coupling beams and the beam-to-wall joints during large deformations into plastic ranges. This study investigated the use of engineered cementitious composite （ECC） in the cast-in-place beam-to-wall joints and the upper regions of the composite coupling beams as an innovative method to improve the seismic performance ofprecast RQ coupled shear walls. Two 1/2-scale precast coupled shear walls were tested under reversed cyclic loading and seismic behavior in terms of failure characteristic, mechanical characteristic value, load-displacement hysteresis curves, load-displacement envelope relationship, stiffness degradation, ductility and energy dissipation capacity were evaluated. Research results show that the substitution of concrete with ECC in the critical cast-in-place regions proved to be an effective method to improve the seismic performance of the two-story spatial of precast RC coupled shear walls.展开更多
Sheathed post-and-beam wooden structures are distinct from light-wood structures.They allow for using sheathing panels that are smaller(0.91 m×1.82 m)than standard-sized panels(1.22 m×2.44 m or 2.44 m×2...Sheathed post-and-beam wooden structures are distinct from light-wood structures.They allow for using sheathing panels that are smaller(0.91 m×1.82 m)than standard-sized panels(1.22 m×2.44 m or 2.44 m×2.44 m).Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear walls.To verify the lateral shear performance of wood frame shear walls with smaller panels,we subjected 13 shear walls,measuring 0.91 m in width and 2.925 m in height,to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses.A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element(FE)software,where a custom nonlinear spring element was used to simulate the sheathing-frame connection.The results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame connection.When same nail specifications were adopted,the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel thickness.The shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5,which satisfied the deformation requirements of residential structures.Based on the test and FE analysis results,the shear strength of the post-and-beam wooden structures with sheathed walls was determined.展开更多
基金supported by National Natural Science Foundation of China(Project No.51878156)EPC Innovation Consulting Project for Longkou Nanshan LNG Phase I Receiving Terminal(Z2000LGENT0399).
文摘To mitigate the challenges in managing the damage level of reinforced concrete(RC)pier columns subjected to cyclic reverse loading,this study conducted a series of cyclic reverse tests on RC pier columns.By analyzing the outcomes of destructive testing on various specimens and fine-tuning the results with the aid of the IMK(Ibarra Medina Krawinkler)recovery model,the energy dissipation capacity coefficient of the pier columns were able to be determined.Furthermore,utilizing the calibrated damage model parameters,the damage index for each specimen were calculated.Based on the obtained damage levels,three distinct pre-damage conditions were designed for the pier columns:minor damage,moderate damage,and severe damage.The study then predicted the variations in hysteresis curves and damage indices under cyclic loading conditions.The experimental findings reveal that the displacement at the top of the pier columns can serve as a reliable indicator for controlling the damage level of pier columns post-loading.Moreover,the calibrated damage index model exhibits proficiency in accurately predicting the damage level of RC pier columns under cyclic loading.
基金Supported by Council of Scientific and Industrial Research(CSIR)-SRF under Award Letter No.09/468/0494/2016 EMR-I。
文摘The structural behaviour of precast shear wall-diaphragm connection was compared with the monolithic connection under seismic loading.The monolithic connection was made by using U-bars connecting shear wall and slab,and the precast connection was made by using dowel bars in two steps.Firstly,U-shaped dowel bars from the precast shear wall lower panel and precast slab were connected by the longitudinal reinforcement,and screed concreting was done above the precast slab.Secondly,the shear wall upper panel was connected using the dowel bar protruding from the shear wall lower panel.The gap between the dowel bars and the duct was filled with non-shrink grout.The specimens were subjected to reverse cyclic loading at the ends of the slab.This study also aimed to develop a 3-D numerical model using ABAQUS software.The non-linear properties of concrete were defined by using the concrete damaged plasticity(CDP)model to analyse the response of the structure.The precast dowel connection between the shear wall and slab showed superior performance concerning ductility,strength,stiffness and energy dissipation.The developed finite element model exactly predicted the behaviour of connections as similar to that of experimental testing in the laboratory.The average difference between the results from finite element analysis and experimental testing was less than 20%.The results point to the conclusion that the shear resistance is provided by the dowel bars and the stiffness of the precast specimen is due to the diaphragm action of the precast slab.The damage parameter and the interaction between structural members play a crucial role in the modelling of precast connections.
文摘The design principles for conventional reinforced concrete structures have gradually transitioned to seismic-resistant design since the 1970s.However,until recently,the implementation of strength capacity and ductility design has not been rigorously enforced inmany developing countries that are prone to seismic risks.Numerous studies have evaluated the effectiveness of joint behavior based on both ductile and non-ductile designs under cyclic loading.Previous research has demonstrated that enhancing joint regions with Ultra-High Performance Steel Fiber Reinforced Concrete(UHPSFRC)significantly improves the seismic resistance of structural components.This paper presents a detailed analysis of the considerable improvements in energy dissipation capacity and stiffness degradation observed in both reinforced test samples compared to the control sample.Furthermore,assessing the effective performance of enhanced reinforced concrete joints is a critical parameter for evaluating the feasibility of this approach.The findings highlight the potential for UHPSFRC to enhance the resilience of concrete structures under seismic loads,providing a viable solution to improve the safety and durability of infrastructure in earthquake-prone regions.This study aims to inform future design methodologies and standards in seismic-resistant construction in developing nations,emphasizing the importance of adopting innovative materials to mitigate earthquake risks effectively.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0701703)the Fundamental Research Funds for the Central Universities+1 种基金Project Supported by the Research and Innovation Program for Graduate Students in Jiangsu(Grant No.KYLX16_0257)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(Grant No.CE02-2-47)
文摘The seismic performance of precast reinforced concrete （RC） coupled shear walls is significantly influenced by coupling beams and the beam-to-wall joints during large deformations into plastic ranges. This study investigated the use of engineered cementitious composite （ECC） in the cast-in-place beam-to-wall joints and the upper regions of the composite coupling beams as an innovative method to improve the seismic performance ofprecast RQ coupled shear walls. Two 1/2-scale precast coupled shear walls were tested under reversed cyclic loading and seismic behavior in terms of failure characteristic, mechanical characteristic value, load-displacement hysteresis curves, load-displacement envelope relationship, stiffness degradation, ductility and energy dissipation capacity were evaluated. Research results show that the substitution of concrete with ECC in the critical cast-in-place regions proved to be an effective method to improve the seismic performance of the two-story spatial of precast RC coupled shear walls.
基金supporting this study with a research grant(No.2019YFD1101001).
文摘Sheathed post-and-beam wooden structures are distinct from light-wood structures.They allow for using sheathing panels that are smaller(0.91 m×1.82 m)than standard-sized panels(1.22 m×2.44 m or 2.44 m×2.44 m).Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear walls.To verify the lateral shear performance of wood frame shear walls with smaller panels,we subjected 13 shear walls,measuring 0.91 m in width and 2.925 m in height,to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses.A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element(FE)software,where a custom nonlinear spring element was used to simulate the sheathing-frame connection.The results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame connection.When same nail specifications were adopted,the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel thickness.The shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5,which satisfied the deformation requirements of residential structures.Based on the test and FE analysis results,the shear strength of the post-and-beam wooden structures with sheathed walls was determined.
