Geometric Nonlinear Static Analysis Of Long-Span Suspension Bridge And Its Program Design

Along with the increase of the spans of suspension bridges, the influence with geometric nonlinear character gets more and more notable. Therefore, how to consider its influence accurately and reasonably in structural analysis has great engineering value and theory significance. According to the strong geometric nonlinear character of long-span suspension bridges, this thesis has explored the calculation of cable curve for suspension bridge and geometric nonlinear analysis theory of suspension bridge. It has put forward some new calculation methods. The main contents about of this thesis are as follows: (1) Segmental catenary theory, an accurate theory of the cable curve for suspension bridge is introduced and two kinds of numerical analysis method for cable is analysed. (2) The basic principles which should be followed in the structural calculation of suspension are elaborated in details, in which the correction calculation of the main cable on saddle's position is generalized into the separate calculation method and the iterating approached calculation method. And this thesis applies these two methods to calculation of combined arc saddle's position. From the viewpoints of NEWTON-RAPHSON iterating method, linetype change stiffness of cable is deduced based on segmental catenary theory. (3) According to the defect of the existed calculation method which is sometimes hard to converge, the concrete numerical analysis method is approved about calculating design linetype for suspension, erection linetype of cable and pre-displacement of saddle without loads, erection linetype of wire strands and linetype of lifting stiffening girders. Based on the above analysis method, the program SUSP_CABLE is compiled on calculation of cable for suspension bridge. Then, Through calculating examples, have verified the correctness of calculation method. (4) Geometric nonlinear solution method whose calculation precision can theoretically converge to an exact solution is proposed. According to the characters of this solution, the calculation formulas of internal force about 2-D truss element, cable element and beam element is deduced. Then the treatment to the problems such as suspension bridge saddle and rigid arm are given. And the calculation method of the internal force under vehicle load concerning geometric nonlinear character is solved. (5) The program SUSP_CAL which is based on the organic combination of analysis law and finite element theory, is described on aspects of main characters and function. Part of these classic examples and contracts are given, and then accuracy and reliability of this program are demonstrated. (6) The program of this thesis is simplified used to the calculation of the cable curve for Pingsheng Bridge in Foshan city and gets more advisable conclusion.