Theoretical And Experimental Study On Multi-Prestressed Steel Structues

Multi-prestressed steel structure is a new system in the steel structures field. . Introducing prestress into steel structures can make full use of material strength, reduce the consumption of steel, improve the mechanics behavior of structutal members, debase the stress peak value, and enhance structural stiffness and stability. Through stepped tensioning and loading such as tensioning→loading→tensioning→…,multi-prestressed steel structures can multiply utilize material strength in elastic range, increase bearing capacity and economizing material further, produc more prestress efficiency. Further more, longer span spatial structure style can be carried out through multi-prestress.In this paper, the stability, optimization, static and dynamic performance and earthquake-resistance capability about multi-prestressed steel structures are studied through those research methods such as theoretical analysis, numerical simulation and model test, et al. The main research work and outcome of this paper are presented as following:1. Stability analysis is carried out with prestressed spatial steel structures according nonlinear finite element theory. Eigenvalue buckling analysis and load-displacement full process buckling analysis on the bases of arc-length method and Newton-Raphson method and nonlinear buckling analysis considering initial flaw based on uniform modal flaw method are carried out with prestressed arch truss. The buckling performance outside plane of prestressed arch truss and the influence of the prestress on structural stability are obtained through buckling analysis. The flaw of the buckling analysis of prestressed steel structures through Ansys is pointed out, which is helpful to the design of these kinds of engineering.2. The optimization model of prestress and cross-section and the resolve method are presented in this paper. Various methods of introducing prestress into the numerical analysis of the prestressed steel structures are summarized and comparied. A new method of optimization of prestress is presented, which takes initial stress as design variable, and takes minimum sum of squares of the structural member stress as objective function. On this base, two-level optimization model of prestress and cross-section for prestressed spatial steel structures is created, which involves the restriction of stress, local stability and displacement. The corresponding programma is...