Effect Of Prestressing Loss On String Truss Structure Seismic Response Analysis

With the development of social economy in our country, in recent years, large-span spatial structures are springing up like mushrooms, String truss structure is large span space structure in which a representative structure. String truss structure is composed of arch truss, cable and pole, and is a typical flexible integration system. Usually, the cable must be applied to a certain degree of prestress, so that the structure has a certain anti camber value in advance, so as to reduce the bending moment caused by the interference of the structure under the action of the load and the bending moment. Therefore, prestressing value using the size and different degree of prestress loss on the structural displacement, internal force distribution is important. Is a problem that can not be ignored, the conclusion through the research analysis can provide some references for the design and construction of truss structure.This paper summarizes the characteristics and present situation of the String truss structure, before the scholars on the basis of the study, to Guangzhou International Convention and Exhibition Center Exhibition Hall steel roof structure as the prototype. String truss structure steel roof model is established by using APDL language in ANSYS software, focus on the different degree of prestress loss effect on self vibration characteristics and seismic response of the String truss structure. The main results are the following contents:(1) The modal analysis of String truss structure is carried out, and the natural vibration characteristics of the structure are understood. And in the prestress loss of the whole truss varying degrees and the different prestress loss combination on the overall structure of the self vibration characteristics of comparative analysis. Different degrees of prestressing losses is obtained, which has little effect on the natural frequency of the structure.(2) When String truss structure input three-dimensional seismic waves, respectively, in the El-Centro wave, Taft wave and Qian’an wave, considered full and part-Pin Truss varying degrees of prestressing losses. String truss structure across nodes in the vertical acceleration displacement across nodes, cross brace axial force in the upper and lower chord stress, stress cable for seismic response of comparative analysis, and comes to a conclusion that the different degree of prestress loss of the degree of the influence of truss string structure seismic response.(3) The seismic wave with the time difference of 0.5s and 1s in the truss structure is analyzed, consistent with the input comparison analysis, and the effect of travel wave effect on the seismic response of truss structure is analyzed. Due to the Guangzhou International Convention and Exhibition Center roof vibration characteristics of the relationship itself, the traveling wave effect has little effect on the seismic response of the roof.