The Collapse Mechanism Study Of Grid Structures Subjected To Strong-Earthquake

In this paper, the collapse modes and mechanism of grids structures subjected tostrong-earthquake are studied. The grids structures are designed with the software3D3S. The progressive collapse process of grids structures are simulated with theexplicit dynamic finite element software ANSYS/LS-DYNA. The collapse rules ofgrids structures are obtained and the anti-collapse design measures for the gridsstructures design is given. The main works and production of this paper as follows:(1) The collapse mechanism of square pyramid grids subjected tostrong-earthquake as follow: The first failure element reult in the elements whichadjacent the first failure element begin to rupture, just as the domino effect; then thelong span crack appears and the short span crack is appearing at the same time. Theyform T crack. At last, the grids structures collapse attributing to the T crack.(2) The collapse mechanism of diagonal square pyramid grids subjected tostrong-earthquake as follow: With the X or Y strong-earthquake militating, the gridsstructures collapse attributing to the angle fault zones. The first failure element is theupper chord middle element, and the failure elements distributing in an area. With theZ strong earthquake militating, the grids structures collapse attributing to the middlecatercorner crack. The first failure element is the web member at the short span edge.With the X and Y strong earthquake militating, the grids structures collapse attributingto the angle fault zone crack. The first failure element is the upper chord at the longspan edge. With the3-d seismic militating, the collapse mode is integration. The firstfailure element is the upper chord middle element, and the failure elementsdistributing in middle area.(3) The collapse mechanism of two-way orthogonal space truss subjected tostrong-earthquake as follow: the first failure element is the upper chord edge element,the failure elements are distributing all around and middle part.The collapse mode andmechanism of two-way orthogonal space truss are all around and T cracks.(4) The collapse mechanism of two-way orthogonal-diagonal lattice gridssubjected to strong-earthquake as follow: The first failure element is the upper chordcorner element, the failure elements are distributing in corner and diagonal. Finally,the two-way orthogonal-diagonal lattice grids collapse with angle and cross faultzones.(5) After discussing the collapse modes and mechanism of four species gridsstructures. The anti-collapse design matures for grids structures are given, and there isa fortune-telling. It is evidently that the anti-earthquake-collapse capacity of gridsstructures is improved.