Research On Component-based Damage Model Of Prestressed Concrete Frame Structure

In recent years,domestic and foreign scholars have proposed a variety of component-based damage model applied to the evaluation of seismic performance of ordinary reinforced concrete frame structures.With the popularization and application of prestressed concrete(PC)frame structure in seismic fortification engineering,it is necessary to evaluate its seismic performance and capacity.Researchers begin to explore the seismic performance and evaluation methods of PC frame structures from a variety of different perspectives.Because of the difference between the bonded and unbonded PC frame structure coupled with the complexity of PC frame structure itself,a reasonable model for the damage assessment of various PC frame structural components has not been proposed.In this paper,the modified Park-Ang damage model which is suitable for the ordinary reinforced concrete structure is choosen,and the effective prestress of prestressed beam is transformed into axial pressure by equivalent load method,the component-based damage model of the bonded and unbonded prestressed concrete beam is studied combining with the results of pseudo static test of existing bonded,unbonded prestressed concrete beams and ordinary reinforced concrete beams,which will provide the basis for the evaluation of the seismic performance of the bonded and unbonded PC frame structure.First of all,this paper focuses on the selection of the results of representative pseudo static test of ordinary reinforced concrete beams,the bonded and unbonded prestressed concrete beam,and the shear span ratio,axial compression ratio,longitudinal reinforcement ratio,stirrup reinforcement ratio,yield load,yield displacement and ultimate displacement are collected seperately.The damage factor calculation method of the bonded and unbonded prestressed concrete beam based on Park-Ang damage model is modified separately.Secondly,the domestic bonded and unbonded PC frame structure test are selected to evaluate the damage by the modified Park-Ang damage model,the reasonable weight method is used to calculate the damage from the component to the whole structure.The applicability and validity of the component-based damage model of the PC frame structure are verified by the actual damage development of the PC frame structure in the experiment.Finally,this paper designs a three-tier,two-span,bonded PC frame structure according to the present specification.Considering the randomness of ground motion,IDA analysis and seismic vulnerability analysis based on component damage model are carried out,what's more,the practicability of the method for seismic performance evaluation of the bonded PC frame structure based on component damage index is further verified and the seismic performance of the bonded PC frame structure is evaluated combining with the analysis results based on maximal story drift angle.