| Under the action of earthquakes,reinforced concrete（RC）columns（or piers）,as the main vertical load-bearing components of structures such as water conservancy and hydropower projects,highways and bridges,buildings and underground projects,carry the vertical loads of the entire structure and the earthquake-induced horizontal load.All previous earthquake damages show that the damage to the RC column in the earthquake is often more serious,endangering the safety of the entire structure.RC columns usually undergo flexure,flexure-shear or shear failures with changes in reinforcement configuration,material strength,and shear span ratio.Post-earthquake investigations have shown that the properties of different failure modes are different,and the seismic performance of RC columns is also different.The hysteretic model can not only reflect the nonlinear relationship between restoring force and displacement,but also describe the strength,stiffness,ductility,energy dissipation capacity and other hysteretic behavior of structural members,which is the comprehensive reflection of seismic performance.Therefore,it is necessary to study the hysteretic model and hysteretic behavior of RC columns under different failure modes to ensure the seismic safety of structures and members.In this paper,the hysteretic model parameters of RC columns under shear（flexure-shear,shear failure）are identified,and the corresponding hysteretic models are established,and the hysteretic performance of RC columns under different seismic failure modes are analyzed.The main research contents are as follows:1.The hysteretic model of single axis BWBN is solved by numerical method,and the characteristics and variation rules of 12 parameters of BWBN model are analyzed by MATLAB software.Then,the applicability and effectiveness of the model are verified and analyzed with the aid of the quasi-static reciprocating loading test data of RC columns in the PEER test database in the United States.2.Based on the quasi-static reciprocating loading test data of RC rectangular section columns（34 pieces of flexure-shear failure and 17 pieces of shear failure）in the PEER test database in the United States,the parameters of BWBN hysteretic model of RC columns under flexural-shear failure and shear failure are identified,and the probability distribution of main influencing parameters is obtained,and then the BWBN hysteretic model of RC columns under two failure modes is obtained.3.With the aid of 9 RC rectangular cross-section columns with different failure modes in the PEER test database in the United States,the finite element model of the RC column was established through the solid element and fiber beam element in the finite element analysis software ABAQUS for numerical simulation.And the hysterestic characteristics of RC columns with different failure modes are analyzed,then the applicability of simulation elements of RC columns with different failure modes is disscussed. |
