Dynamic Response Analysis And Study On The Seismic Characteristics Of The Beam String Structure

A new type of self-balance structure-Beam String Structure (BSS) which is composed of strings, struts and moment-resistant elements is presented in this paper. The stress of its members is succinct and definite, tension and compression members complementing each other and cooperating to making full use of advantages of different materials, which is a typical hybrid system with the combination of rigid and flexibility in large span structures. Because of the reasonable mechanical performance of BSS and the broad developmental space of the large span structure in our country, it is sure that the structure will be used more and more widely.Based on the existing researching finding on BSS and the prestressed spatial truss string structure, taking use of the large common finite element program ANSYS; the dynamic properties of BSS were studied as follows:(1) Taking use of the APDL(ANSYS Parametric Design Language) in ANSYS, this paper develop the special parametric program for the model building and the solution of BSS, which settles firm base for the intensive study of the mechanical performance and the optimization design of the structure.(2) The finite element model of the structure was formed through reasonable simplification. And model shapes were studies by using the famous program of ANSYS.(3) Responsible formulations were used to describe the dynamic actions of BSS while appropriate method was chosen to solve these problems on the base of forgone researches.(4) Long span beam string structures' responses to uniform excitation of earthquake were discussed. Through a large amount of analysis of the different parameters, for example, the rise-span ratio, the sag-span ratio, the number of struts, the prestress and the oblique angle etc, there-dimension excitation and traveling wave effect were introduced in this structure with geometric nonlinear being considered. Through comparing the structures' properties and the seismic responses with geometric nonlinear, results from the analysis supplied some useable conclusion for us to make further researches as well as practices, which may be a reference for project design.(5) Multi-dimension asynchronous excitations were imposed on the structure and the beam string structures' seismic response time histories were discussed. Displacement time histories which were used to excite the structure piers were gotten by twice integral of acceleration time histories. The effects of the parameters of BSS and traveling wave effect on seismic response are discussed in detail here.