| Recycled concrete filled steel tube is a kind of composite member formed by filling recycled concrete in steel pipe,the mechanical characteristics in the structure are influenced by components and the form of structure,at home and abroad,the research of recycled concrete filled steel tube mainly concentrates on the performance of components at present,the anti-seismic performance of recycled concrete filled steel tube structure is less studied.Apply recycled concrete to conmposite structure of concrete filled steel tube,not only realize the recycling of waste concrete,but also save the costs of construction,it has certain guiding significance for practical engineering application.Based on the measured data of recycled concrete,10 floors of concrete filled steel tube(CFST)and recycled concrete filled steel tube(RCFST)frame systems were selected,ANSYS finite element models and SAP2000 validation models were established.Modal analysis,response spectrum and dynamic time history analysis of the two models were carried out by ANSYS,dynamic characteristics and anti-seismic performance of the two models under same conditions were compared.The main works are as follows:(1)The results of modal analysis and response spectrum analysis of ANASYS models were compared with the results of SAP2000 verification models,it shows that the calculations of the two finite element software are similar,and the ANSYS finite element models are reasonable,which can accurately analyze anti-seismic performance of CFST and RCFST frame systems.(2)Modal analysis of CFST and RCFST frame systems were conducted,natural vibration frequency distribution diagram,period and vibration diagram of the two models were compared,and the difference of dynamic characteristics between the two models were studied.The analysis results indicate that natural vibration frequency is reduced with the addition of recycled concrete,the maximum decline is 3%,but it does not change vibration modes of the structures.(3)Response spectrum analysis of CFST and RCFST frame systems were conducted,structural responses of the two models under the action of earthquake in X direction and Y direction were calculated respectively,structural displacement and internal force of the two models were compared.The results show that with the addition of recycled concrete,displacement response is increased,the maximum increase is 5%,however,seismic shear strength is reduced,the maximum decline is 3%.(4)Dynamic time history analysis of CFST and RCFST frame systems under the action of frequent earthquake and rare earthquake were carried out,dynamic responses of the two models,such as seismic shear,structural displacement,storey drift and acceleration,were compared.The results indicate that seismic shear of the structure is reduced with the addition of recycled concrete,and the maximum decline is 10%,while the maximum top floor displacement and story drift are changed in different trend under the action of different seismic waves,but the difference is not large.Recycled concrete filled steel tube frame system still has good seismic performance under the action of earthquake,it can be applied to construction engineering. |
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