Spatial Structural Behavior And Time-Dependent Analysis Of Composite Cable Stayed Bridge

Composite cable-stayed bridges are widely used in China, but the researches ontheir spatial structural behavior and time-dependent effect are not fully addressed. Bymeans of specimen tests, theoretical and numerical analyses, the spatial structuralbehavior and time-dependent effect of composite cable-stayed bridge are studied, andthen a series of complete practical design methods are proposed.The main work of this thesis including7concepts:1) A theoretical modelconsidering both shear lag in the flange and slip effect on the interface ofsteel-concrete composite girder is established, and then the theory model andanalytical solutions are verified by test results and finite element analysis(chapter2).2) With fully recognized of structural behavior of corrugated web, a new type of cablestayed bridge with composite girder consisting of corrugated web is proposed, andthen beam model considering shear deformation in the web is established. Byintroducing warping displacement function, the theoretical model considering bothshear lag in the flange and shear deformation in the web of composite girder withcorrugated webs is established (chapter3).3) Tests of three composite girders withdifferent sections under the combination loads of bending moment and axial force areconductted (chapter4).4) According to the works of specimen tests, theoretical andnumerical analyses, a series of practical design methods of composite girder incomposite cable stayed bridge are proposed in component and structural systemlevels (chapter5).5) By introducing gradually recursive calculation method inconcrete creep analysis, three-dimension concrete creep and shrinkage analysisprogram are developed based on the user subroutine of finite element analysissoftware ABAQUS, and then the reliability of the program is verified by comparingwith the existing tests and engineering example analysis (chapter6).6) Byembedding stayed cables multi-drawing program and concrete creep and shrinkageanalysis program into three-dimension cable stayed bridge spatial model, the complexspatial structural behavior of composite cable stayed bridge in all stages are studied,and then practical design methods of composite girder are proved to be reliable(chapter7).7) Considering the whole construction stages, the time-dependent effects of composite cable stayed bridges with different types of girders are studied. Then,the age-adjusted effective modulus method is introduced to analysis time-dependenteffect of composite cable-stayed bridge, which may give a more simplified processduring preliminary design stage (chapter8).This dissertation is sponsored by National Natural Science Foundation ofChina (NSFC) program (#50438020).