Yield Point Determination Method And Its Effect On Seismic Performance Evaluation Of Structures

In the field of structural earthquake resistance,evaluating the elastoplastic performance of a structure or component is an important and fundamental task.To accurately quantify the elastoplastic properties of a structure or component,it is particularly critical to accurately define the yield point.In the early research work,many scholars have proposed a variety of methods to determine the yield point,but the elastoplastic performance parameters of structures or members calculated based on different methods,such as ductility coefficient,damage index,and hysteresis model characteristic parameters,are quite different.As a result,there is a significant difference in the seismic performance evaluation of components and structures.Therefore,in this paper,the method of determining the yield point of the member is used as the starting point.First,the common loading method is used for the beam-column member to discuss the feasibility of defining the member yield by the key material yield of the member;then,based on the member ductility coefficient,by collecting test data,according to The increase in the coupling ratio will lead to the increase of the ductility of the member,the longitudinal reinforcement needs to reach the yield when the member is yielded,and the ductility coefficient cannot show large dispersion.The comparative study of various yield point determination methods is conducted to determine the application of various yield point determination methods.Then,the Park-Ang double-parameter failure criterion was introduced.By collecting data,a method for determining the yield shear force suitable for calculating the damage index of the component was studied.Finally,based on the fiber model established by PERFORM-3D,The elastoplastic performance of the structure was simulated and analyzed.Based on the two-line restoring force model,the impact of the restoring force model determined by different yield point determination methods on the seismic performance evaluation of the structure was studied by inputting seismic waves of different strengths to various structures.Based on the above research work,the main conclusions of this article are as follows:(1)The definition of the critical material yield as a member’s yield point has certain limitations.For a member that can appear a long yield section at the same time,such as a three-point load reinforced concrete suitable reinforcement beam,this definition is applicable,but not for other members.(2)Among the six methods for determining the yield point,the intersection perpendicular method,the primary perpendicular method,and the secondary perpendicular method are not suitable for determining the yield point of the member used to calculate the ductility coefficient;the farthest point method,0.75 Fu method,energy method One is applicable in determining the ductility coefficient of components.(3)Based on the six yield point determination methods,the yield shear force of the component has obvious differences in calculating the Park-Ang damage index of the component.Among them,the yield damage value determined by the energy method 1 is calculated and the theoretical damage index when the component is damaged is 1 is the most consistent,so when calculating the damage index of the component,it is recommended to use the energy method to determine the yield shear force.(4)When the two-line restoring force model is used to evaluate the seismic performance of the structure,the energy method 1 is more accurate for evaluating the layer shear force and layer displacement of the structure;the two-line restoring force of the component determined by the farthest point method and the 0.75 Fu method The model is more accurate for grasping the damage degree of components and structures.