Research On Seismic Performance And Collapse Resistance Of RACFST Frame-SPCCAW Core Structure

With the rapid development of the construction industry,the resulting waste concrete has also risen sharply.How to treat and utilize waste concrete and recycle it for reuse has become a hot topic.Recycled aggregate concrete filled steel tube(RACFST)not only shows good mechanical properties,but also can effectively utilize renewable resources such as waste concrete,which is of economic and environmental significance;Steel plate concrete combined shear wall(SPCCSW)mainly bears horizontal force in the frame-core structure,its structural system has good ductile and lateral force resistance;RACFST is applied to the frame-SPCCSW core structure system,form the new RACFST frame-SPCCSW core structure.This paper mainly studies the seismic performance of RACFST member and structure,and research the ability of the structural collapse resistance,The main research contents and research results are as follows:In terms of components: The seismic performance of rectangular RACFST columns with different recycled aggregate substitution ratios are studied,the failure modes,stress and deformation development trends,ductility and energy dissipation are analyzed.The results show that the bottom drum deformation occurred in rectangular RACFST columns with different recycled aggregate substitution ratio,they have similar failure modes and hysteresis curves and strong energy consumption of components.With the increase of recycled aggregate substitution ratio,the ultimate bearing capacity of rectangular RACFST columns are slightly reduced,the ductility coefficient and equivalent viscous damping coefficient vary within ±5%,the seismic deformation resistance of the component is not affected by recycledaggregate substitution ratio;the ultimate bearing capacity,ductility and hysteretic energy dissipation capacity of the RACFST column with 30% recycled aggregate substitution ratio are relatively better;From the perspective of ultimate bearing capacity,seismic ductility and energy consumption,recycled concrete can be applied to rectangular concrete filled steel tube(CFST)column.Structural aspect: Parameter analysis of the properties of RACFST frame-SPCCSW core structure from different recycled aggregate substitution ratios rectangular RACFST columns,steel thickness and steel plate thickness in SPCCSW.Based on a practical project,the static elastoplastic analysis,structural performance index analysis and dynamic time history analysis of the RACFST frame-SPCCSW core structure is analyzed.The structure ductility,deformation law,shear distribution,stiffness degradation,damage mechanism and plastic hinge are studied,verify structure meet seismic fortification requirements,and the analysis of structural continuous collapse resistance.The results show that the overall stability of RACFST frame-SPCCSW core structure with 30% recycled aggregate substitution rate has little difference with the CFST frame-SPCCSW core structure.With the increase of the concrete thickness and steel plate thickness in the SPCCSW,the overall stiffness improvement rate of the structure is continuously reduced,reasonable improvement of steel plate thickness can significantly improve the seismic performance of the structure,The thickness of concrete and steel plate in the SPCCSW should be selected within a reasonable range of 200mm~600mm and 20mm~50mm respectively.With the increase of recycled aggregate substitution ratio,the overall stiffness of the structure is reduced,the shear force of the base is reduced,the structure lateral shift is relatively increased,and the recycled aggregate substitution rate has no greater influence on the ductility of the RACFST frame-SPCCSW core structure,the structural ductility ratio is about 8,the elastic-plasticity of large earthquakes and the elastic base shear ratio of small earthquakes are about 4 times,the structure overall stiffness degrade is better.Under the rare earthquake,87% of the plastic hinged members are in the B-LS strengthening state,7% are in the LS-CP unloading phase,6% are in the CP-E failure phase,the important components are basically in a safe state,and a few components are destroyed,the overall structure has not collapsed,and the structure has sufficient seismic capacity to meet the seismic performance requirements of “big earthquakesdo not fall”.The failure of the middle column and the side column failure structure in the bottom layer will not cause continuous collapse,and the failure of the bottom layer weak corner column may cause a small range of continuous collapse of the structure corners,the ability of the whole structural resistance continuous collapse is good.