Study On Thermal Expansion Coefficient Of Cable And Structural Performance Of Prestressed Steel Structure Under Temperature Action

Nowadays the prestressed steel structure is one of the most popular and potential structures, and in this kind of structure cable is usually adopted as tension unit. However thermal expansion coefficient of cable, which is one of their major characteristics, has not exact values in past research. Moreover current data don't agree with each other, and the thermal expansion coefficients of cables is often substituted by pure steel's to analyze structures. Based on the investigation of existing equipments and instruments for measuring the thermal expansion coefficient of cables, a conclusion is drawn that none is satisfied. So two thermal expansion instruments by air-heating and water-heating are designed and manufactured. With them the thermal expansion coefficients of cables, which are usually used in engineering facts, are measured.The thermal expansion coefficients of cables are measured by actual test. And test data are analyzed and processed by the ORIGIN data processing software, with which the value of the thermal expansion coefficients of cables are determined.Then the data got from above experiment are used to analyze prestressed structures. Prestress of circle cables are setting in the case of a suspendom with 35.4m span and 4.6m rise. Here the model building, form finding, and mechanical performance under temperature action of this suspendome are analyzed by ANSYS finite element analysis software, in which the changes of the mechanical performance of circle cables and other structural members is calculated just under temperature load. Different thermal expansion coefficients (which are acquired from existing documents and experiments) are adopted in order to acquire the separately changes of prestress and inner force of the suspendome. Meantime the importance of the thermal expansion coefficient to the mechanical performance of prestressed space steel structure is also analyzed.The contrast of the influence to the mechanical performance of the prestressed space steel structure, the cable stayed structure and the beam string structure is also analyzed by adopting different thermal expansion coefficients.In the end, research results are summarized and some conclusions are drawn, which can be refereed by engineering facts. Some questions to be deeply studied and prospects of the paper's signifacation are also proposed.