Simulation Study Of R.C. Frame Structure Progressive Collapse Based On Degenerated Three-dimension Solid Virtual Laminated Element Theory

Based on the theory of three-dimensional solid virtual laminated element, thispaper researches a finite element method of three dimensional simulation analysiswhich can be used in reinforced concrete structure system framework. This spatialnonlinear finite element analysis program is based upon the degeneratedthree-dimensional solid performance of laminated element theory, and we use thistheory to analysis some examples of frame structure progressive collapse. The maincontent of this paper as follows.(1) To explore a method that has rationality and applicability of threedimensional simulation of nonlinear finite element analysis program, which will beused to analysis ultimate bearing capacity of reinforced concrete frame structure. Thisanalysis program is based on the degenerated three-dimensional solid virtuallaminated element theory.(2) Tried to show how to analysis three dimensional stress and elastic-plasticdeformation of reinforced concrete frame structure, which adopt the threedimensional simulation of nonlinear finite element analysis program of degeneratedthree-dimensional solid virtual laminated element theory. At the same time, we canobtain morphological damage to space of reinforced concrete frame structure. Thisresearch has reached a basis for the following analysis of Reinforced concrete framestructure’s progressive collapse.(3) Combine the above theory and alternate path method, which means weshould remove columns respectively, corner column,side column,middle column andfloor slab, we analysis the process of continuous collapse of one layer, two layerreinforced concrete frame structure by simulation. At the same time, we research thechange and failure mechanism of ultimate bearing capacity. According to research, nofactor has affected ultimate bearing capacity more than removing middle column, theinfluence of removing side column is more than removing corner column andremoving floor slab.(4) In current research of progressive collapse accident of reinforced concrete frame structure，it is very difficult to simulate the Effects and reinforcement ofconcrete slab by traditional software of finite element analysis. In this paper, we adoptnonlinear finite element analysis program of three dimensional simulation, which isbased on the element theory of degenerated three-dimensional solid virtual laminated.By imitating frame column, beam, slab and reinforced, we discussed the influence ofbeam-slab structure on reinforced concrete when the reinforced concrete framestructure begin progressive collapse. In other words, we built the analysis mode inwhich the frame column has enough bearing capacity and the general failure of framestructure appears as the Failure of beam slab structure. We considered the differenceabout the thickness of the plate, reinforcement ratio of the bottom plate andreinforcement ratio of the top plate, and discussed the influence of this difference onprogressive collapse of reinforced concrete frame structure.