| Cable supported structure is a advanced and efficient pre-stressed steel structure systembased upon the tensegrity concept. Generally, the structure is composed of upper structure(beam, reticulated shell, truss, etc), lower cables, and vertical struts that connect both of them.By prestressing the cables, the stress and distortion situation of upper structure can beimproved significantly. Cable supported structure pushing the limits of traditional spacestructure, and has been widely used in many of buildings such as gymnasium, theater, railwaystation, airport. Especially since2008Beijing Olympic Games, because of the development ofChina’s sports undertaking, a lot of gymnasium has been constructed in different locations.Cable supported structure has been adopted in many venues of different styles,and derivesvarious structural style.This article is based on the multiple suspended beam roof of Shanxi Olympic Gymnasium.The upper part of the roof is single layer reticulated shell that is composed of two-wayorthogonal box-section beams, the central part is vertical struts made of circular steel tubes,and the lower part is cables made of high strength steel wire bundle and inclined steel rods.The three part combines as a unified whole and bears external load together. This structurehas reasonable stress and spatial integrity. But the loading path of the structure is complicated,the similar project experiences is lack, and the theoretical research of this structure isimperfection. To further understand the performance of monolithic structure, the steel roof ofthe velodrome was simulated by ABAQUS finite element analysis software, the stress state ofthe structure under dead load and live load was analyzed. The computed result was comparedwith the construction monitoring data, validated the finite element mode. Based on the model,analyzed the mechanical property of multiple suspended beam, and obtained the followingmain conclusions: (1) The mechanics property analysis indicates that the deflection of the mid-span,support reaction and moments of top chords in the multiple suspended beam is much smallerthan that in reticulated shell. Prestress makes a major contribution to the aspects above.(2) Use the subspace method to analyze the vibration characteristic of the structure. Theresults show that the vibration frequencies increases gently with the increase of modes order,and there is not a sudden change. The vibration frequencies is much bigger and more complexthan it of reticulated shell. For the cases with fixed support, the vibration frequencies raise10%compares to the cases with simple support. The vibration frequencies decreases to someextent with the increase of load. Prestress has small impact on vibration characteristic.(3) Linear buckling analysis shows that the buckling modes with more vertexes appearsearlier in multiple suspended beam than in reticulated shell, and the eigenvalue increasesobviously. Non-linear buckling analysis with arc-length method shows that critical load ofmultiple suspended beam increases significantly. Consider geometry nonlinear and materialnonlinear reduces stability of the structure evidently. The stability declines sharply with theincrease of initial imperfection. In addition, supporting condition, live load, distribution ofimperfection have different level of effects on stability of the structure.(4) To analysis the seismic response of multiple suspended beam by dynamicelastic-plastic time history analysis, the result indicates that displacement response and thenumber of plastic members of multiple suspended beam is much smaller than that of latticedshell. Judging by B-R principle, the dynamic stability of multiple suspended beam increasessignificantly. The structure is sensitive to vertical earthquake. Seismic response of thestructure under different earthquakes is different, too. In order to conforming to the code,choosing more earthquake records and paying attention to vertical earthquake in analyzingprogress is necessary. |
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