Progressive Collapse Analysis Of Prefabricated Reinforced Concrete Frame Structures Connected By Sleeve Grouting

Progressive collapse performance is the theoretical basis for the study of structural design methods against progressive collapse.In this paper,the progressive collapse resistance of the reinforced concrete(RC)frame structure is systematically studied.The main research work and achievements are as follows:(1)Mechanical properties of the assembled RC frame node connected by sleeve grouting.Based on the numerical analysis model,the skeleton curve of the assembled RC frame node connected by sleeve grouting is obtained.According to the characteristics of the skeleton curve,the bending moment-corner model is set as a quadruple line relationship,and the calculation formula of each turning point parameter is obtained by using data fitting.(2)Numerical analysis model of progressive collapse of prefabricated RC frame structure connected by sleeve grouting.Based on the finite element software SAP2000 with its own connecting unit to simulate the mechanical properties of the sleeve grouting connection,a numerical analysis model of the progressive collapse of the assembled RC frame structure is established,and the accuracy and efficiency of the model are verified by a series of examples.(3)Analysis and evaluation of progressive collapse resistance of prefabricated RC frame structure with sleeve grouting connection.By using the nonlinear dynamic removal component method and the nonlinear static Pushdown method,the mechanism and distribution of resistance to progressive collapse of the assembled RC frame structure designed according to the standard of our country is studied,which provides a basis for further analysis of the design method for progressive collapse.Two evaluation indexes of RC frame structure resistance to progressive collapse,including probability of collapse and bearing capacity reserve,are proposed.The results show that these two evaluation indexes can comprehensively evaluate the structure's resistance to progressive collapse from two aspects: the overall structure and the local structure weakness.(4)Suggestions on engineering design methods of prefabricated RC frame structure with sleeve grouting connection to resist progressive collapse.A numerical example is used to verify that the RC frame structure of the sleeve grouting connection is designed to resist progressive collapse by using the nonlinear dynamic and linear static methods of the alternate path method.The results show that the two design schemes can ensure that the RC frame structure of the sleeve grouting connection meets the need of progressive collapse.By means of example,the design effect of the existing tensile strength method and the improved tensile strength method against progressive collapse is tested.It is found that the existing tensile strength method can not guarantee that the assembled RC frame structure of the sleeve grouting connection meets the requirements for progressive collapse.The improved strength method can ensure that the RC frame structure of sleeve grouting connection under partial column removal can meet the demand of progressive collapse.