| This paper concerns geometric nonlinear analysis of bridge structure and software development, mainly concentrating on the analysis for suspension bridge. It consists of two parts, calculation of cable curve for suspension bridge and geometric nonlinear analysis of bridge structure.The main contents about calculation of cable curve for suspension bridges are as follows:Firstly, parabola theory, a traditional calculation theory of linetype for suspension bridge, is introduced. According to behavior of suspension bridge, segmental catenary theory which is an exact calculation theory of cable curve for suspension bridges is then built. After that, the errors and adaptable range of segmental parabola theory, segmental straight-line theory and traditional parabola theory are compared one another. And then the effect of the change of cable length and span and the redistribution of dead load due to deformation on cable curve are analyzed.Secondly, calculation theory of construction for suspension bridge is presented under the ideal condition of dead load design. Linetype change stiffness of cable and slip stiffness of supporting points are deduced based on segmental catenary theory. Then numerical analysis method through SGKZ2000 software are introduced in detail about calculating design linetype for suspension bridge, unstressed length of cable, erection linetype of cable and pre-displacement of saddle without loads, erection linetype of wire strands, the fixed position for erecting cable band and linetype of lifting stiffening girders.Finally, the contents and approaches of construction control for suspension bridge are described. Construction calculation for several suspension bridges is made using SGKZ2000 software. This paper also presents the methods of controlling unstressed length of cable, pre-displacement of saddle, anchor span tension, erection of wire strands, the fixed position for erecting cable band and cable length. Determination and control approach of displacement of saddles during cable erection are also introduced. At the same time, the change course of linetype during construction period for suspension bridge is analyzed.The main contents about geometric nonlinear analysis of bridge structure are as follows:First of all, geometric nonlinear solution method whose calculation precisiondoesn't depend on tangent stiffness matrix but can converge to an exact solution is proposed. According to the characters of this solution, solution method of loads and internal force vectors to achieve the highly precise results is introduced, determination of coordinate system and matrix of coordinate transformation about the problem of 3-D large rotation and the method of calculating rotational deformation directly from local coordination system and cross-section coordination system are presented, and then the treatment to the problems such as beam element, truss element, cable element, cable-membrane element, saddle element, supporting element, uniaxial force element, gap element and release of degree of freedom of elements and etc are given.Then, author introduces geometric nonlinear analysis theory, geometric nonlinear calculation theory during construction period, load position of live load considering geometric nonlinear and calculation theory of worst-case value, static time history theory for vehicle running, geometric nonlinear analysis theory of natural vibration and structural dynamic reaction and so on. All of these theories fit any appointed structure with corresponding programs. So a series of completed analysis approaches that cover all geometric nonlinear factors of bridge structure are formed.And then, SGKZ2000 which is a special software for cable design and construction calculation for suspension bridge and BCAS2000, a 3-D geometric nonlinear static and dynamic analysis software for bridge structure, are described on aspects of main characters, function, applying condition in engineering, interface and program technology. Part of these classic examples and contracts are...
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