Presented herein is an experimental study on seismic resistance of rectangular steel reinforced concrete (SRC) columns confined with a new type of multi-spiral cage. The multi-spiral cage is a device of five interconn...Presented herein is an experimental study on seismic resistance of rectangular steel reinforced concrete (SRC) columns confined with a new type of multi-spiral cage. The multi-spiral cage is a device of five interconnected spirals, named "5-spirals", with a large spiral at the center and four small ones at the corners. The innovation of applying the 5-spirals to SRC column is to take its superiority in concrete confinement and efficiency in automatic production for the precast construction industry. Four full-scale SRC columns were tested under horizontal cyclic loading. All of the tested columns were capable of sustaining a drift angle up to 6% radians. The hysteresis loops observed from the cyclic loading tests indicated that the spirally confined SRC columns demonstrated excellent performances in both strength and ductility. The test results suggested that with significant saving of the confinement steel, the newly innovated 5-spirals can be successfully applied to the precast rectangular SRC columns.展开更多
To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial co...To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.展开更多
This study investigates the seismic performance of multiple reinforcement,high-strength concrete(MRHSC)columns that are characterized by multiple transverse and longitudinal reinforcements in core areas.Eight MRHSC co...This study investigates the seismic performance of multiple reinforcement,high-strength concrete(MRHSC)columns that are characterized by multiple transverse and longitudinal reinforcements in core areas.Eight MRHSC columns were designed and subjected to a low cycle,reversed loading test.The response,including the failure modes,hysteretic behavior,lateral bearing capacity,and displacement ductility,was analyzed.The effects of the axial compression ratio,stirrup form,and stirrup spacing of the central reinforcement configuration on the seismic performance of the columns were studied.Furthermore,an analytical model was developed to predict the backbone force-displacement curves of the MRHSC columns.The test results showed that these columns experienced two failure modes:shear failure and flexure-shear failure.As the axial compression ratio increased,the bearing capacity increased significantly,whereas the deformation capacity and ductility decreased.A decrease in the spacing of central transverse reinforcements improved the ductility and delayed the degradation of load-bearing capacity.The proposed analytical model can accurately predict the lateral force and deformations of MRHSC columns.展开更多
文摘Presented herein is an experimental study on seismic resistance of rectangular steel reinforced concrete (SRC) columns confined with a new type of multi-spiral cage. The multi-spiral cage is a device of five interconnected spirals, named "5-spirals", with a large spiral at the center and four small ones at the corners. The innovation of applying the 5-spirals to SRC column is to take its superiority in concrete confinement and efficiency in automatic production for the precast construction industry. Four full-scale SRC columns were tested under horizontal cyclic loading. All of the tested columns were capable of sustaining a drift angle up to 6% radians. The hysteresis loops observed from the cyclic loading tests indicated that the spirally confined SRC columns demonstrated excellent performances in both strength and ductility. The test results suggested that with significant saving of the confinement steel, the newly innovated 5-spirals can be successfully applied to the precast rectangular SRC columns.
基金Supported by National Natural Science Foundation of China (No. 50878141)Hebei Natural Science Foundation,China (No. E2011202013)High School of Hebei Science and Technology Research Youth Foundation,China(No. Q2012083)
文摘To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.
基金Natural Science Foundation of China(NSFC)under Grant No.51868073Special Funds for Technology Innovation Guidance of Shaanxi under Grant No.2019CGHJ-06+1 种基金Natural Science Foundation of Shaanxi under Grant No.2018JQ5005Special Fund for Basic Scientific Research of Central Colleges under Grant No.300102288302。
文摘This study investigates the seismic performance of multiple reinforcement,high-strength concrete(MRHSC)columns that are characterized by multiple transverse and longitudinal reinforcements in core areas.Eight MRHSC columns were designed and subjected to a low cycle,reversed loading test.The response,including the failure modes,hysteretic behavior,lateral bearing capacity,and displacement ductility,was analyzed.The effects of the axial compression ratio,stirrup form,and stirrup spacing of the central reinforcement configuration on the seismic performance of the columns were studied.Furthermore,an analytical model was developed to predict the backbone force-displacement curves of the MRHSC columns.The test results showed that these columns experienced two failure modes:shear failure and flexure-shear failure.As the axial compression ratio increased,the bearing capacity increased significantly,whereas the deformation capacity and ductility decreased.A decrease in the spacing of central transverse reinforcements improved the ductility and delayed the degradation of load-bearing capacity.The proposed analytical model can accurately predict the lateral force and deformations of MRHSC columns.
