Seismic Performance Evaluation Method And Application Of Concrete Frame Structures With Damage And Defects

In recent years,due to the impact of earthquake disasters,a large number of buildings have been damaged.At the same time,the early buildings have defective problems due to imperfect standard and durability damage for long-term use.So it is of great significance to assess seismic performance of structures with damage and defects.In this paper,the concrete frame structure is taken as the research object to study the analytical model of the damage structure.This paper are mainly divided into three parts: study on durability damage model,seismic damage model and layer damage model of frame structure.The main research work and achievements of this paper are as follows:1.Constitutive models of carbonized concrete,corroded reinforcements and bonding slip of corroded reinforced concrete are described.Through the case,the constitutive model of the degraded material is modified.The effects of concrete carbonation and reinforcement corrosion on the seismic performance of the whole structure are analyzed.2.Based on the existing research results,the establishing process of restoring force skeleton curve of seismic damage component is analyzed,and the establishing method of plastic hinge model of seismic damage component is put forward.According to the seismic damage model proposed by Park-Ang and the hysteresis curve information of 39 components,the stiffness,strength degradation coefficient and residual deformation of structural components under different damage conditions are obtained.The seismic hazard description is linked with the damage index,and the stiffness,the strength degradation coefficient and the residual deformation of the components are determined by the appearance damage.The damage levels of the structure are determined according to the structure pushover curve.This chapter intents to determine the relationship between the stiffness,the strength,the residual deformation and the damage levels of the structural components by the hysteresis curves information of 10 concrete columns and 10 concrete beams.The data are fitted to obtain the stiffness,strength degradation coefficient and the residual deformation of the structural components under different damage levels.3.For the damage structure,a Bayesian method for physical parameter recognition based on modal is used to identify the layer stiffness of the damaged structure.According to the recognition result,the key parameters of layer restoring force skeleton curve of the damaged structure are calculated,the layer restoring force model of the damaged structure is obtained.A rapid evaluation method for seismic performance of damaged structures based on layer model is proposed.4.Based on the analytical model of the structural components proposed in this paper,the plastic hinge model of the damaged structural component is modified by using SAP2000 as the analysis platform.The seismic performance of the damaged structure is evaluated by the static elastic-plastic analysis and dynamic time history analysis method.The results show that the stiffness,strength and ductility of the whole structure are reduced after the damage of the structure,and the interlayer displacement angle of the structure is increased.Based onthis example,the concrete frame structure is equivalent to the shear layer model,and the layer restoring force model of the damage structure is established.The simplified model is analyzed and the results are compared with the results of the structure without simplification to verify the feasibility of the proposed layer restoring force model of the damaged structure.