Study On Shear Capacity And Deformation Capacity Of Reinforced Concrete Columns Subjected To Flexure-shear Failure Under Seismic Load

Reinforced concrete(RC)columns as the main vertical load-bearing elements of hydropower station,pumping plant house,aqueduct,and highway bridges,plays a crucial role in overall structural performance and easily fail under seismic load.Once the reinforced concrete columns destruction will endanger the safety of the structure,causing a large number of casualties.Located in the junction of the world’s two major seismic belt,China is a multi-earthquake-happening country,especially in the southwest region,which is China’s hydropower development center with high-frequent earthquakes.Therefore,investigations on the failure modes and seismic performance of RC columns are necessary.Effective measures should be taken to ensure that the columns develop sufficient bearing capacity and ductility to absorb large seismic energy.Accordingly,RC columns in flexural-shear under seismic loads is studied in this paper,and the main content and conclusion are listed as follow:1 From the PEER(the Pacific Earthquake Engineering Research Center,USA)database for seismic performance testing of the columns,the quasi-static test data of 16 rectangular section columns failed in flexural-shear were collected.Through statistical analysis,the reliability of the shear capacity as provided in the standard of water conservancy industry in China,the Design Code for Hydraulic Concrete Structures(SL/T191-96)and the Design Code for Hydraulic Concrete Structures(SL191-2008)and in the standard of electric power industry in China,the Design Specification for Hydraulic Concrete Structures(DL/T5057-2009)and the main bridge seismic design specifications of the USA and Europe were evaluated.And then the main factors affecting the shear capacity of RC columns subjected to flexure-shear failure are analyzed.2 From the PEER(the Pacific Earthquake Engineering Research Center,USA)database for seismic performance testing of the columns,the quasi-static test data of 16 rectangular section columns failed in flexural-shear were collected.The lateral deformation of RC columns: reliability calculation model of plastic hinge model,Saatcioglu model,Sugano model,and Razvi Elwood and Moehle model were collected to evaluate.And then the main factors affecting the deformation capacity of RC columns subjected to flexure-shear failure are analyzed.3 By using FORTRAN program,the full curvature analysis of RC columns in flexureshear failure is carried out,and the moment-curvature diagram is obtained with analyzing the constitution of the later deformation.The flexure deformation and shear deformation as well as the deformation caused by pull-out of longitudinal reinforcement of RC columns are combined to calculate the skeleton curve of columns in flexure-shear failure.4 The calculated skeleton curves and the hysteretic curves of the test columns are compared,and the main factors affecting the shearing capacity and ductility of the RC columns are analyzed.Research shows that the modal predicted the load-deformation response envelop reasonably well,so it can be used to calculate the skeleton curve and analyze the deformation capacity of RC columns subjected to combined action of axial load and lateral load.