Research On Stability Of Large Composite Truss

Steel-concrete composite truss has a wide range application prospects in the construction field due to the advantages of both truss structure and composite structure. Currently, research on composite truss which is a new type structure is still not perfect. Research on composite truss is in its infancy in China, less study on stabilizing properties have been done, no standard reference can be referred.In the paper, the stability capacity of external node and ear plate node are analyzed with finite element analysis based on the existing test, the main research contents are as follows:(1) Finite element analysis is employed to do eigenvalue buckling analysis on the composite truss under horizontal load. Ten order buckling modes of external node and ear plate node are analyzed, the status characteristics of buckling critical point on the two types of nodes are studied.(2) Parameter analysis is carried out to research composite truss’ stability capacity. The effects of bending stiffness of ventral pole and thickness of the gusset plate on buckling load are analyzed on composite truss. Studies have shown when stiffness of ventral pole increased, the buckling load increased, and the influence of thickness of the gusset plate on composite truss buckling load is weak.(3)The overall stability on composite truss is analyzed. The relationship of moment rotation is studied on semi-rigid nodes, which establish a basis for the study of the overall stability. The finite element models of different loads are created, the effects on the overall stability are analyzed which are applied by china-live-load and UIC live-load. Truss buckling modes and buckling loads are calculated, buckling load of semi-rigid connection is higher.(4) Parameter analysis is carried out to research composite truss structure’ stability capacity, with aspect ratio, cross-height ratio, bending stiffness of ventral pole,employing the finite element model which has been established. Research shows buckling load can be obviously improved by increasing the aspect ratio and bending stifness of ventral pole, the higher cross-height ratio, the more decrease buckling load.