| As a combination of steel-concrete composite structure and rigid frame bridge, thesteel-concrete composite rigid frame bridge has many advantages in mechanicalperformance, total cost, construction speed and durability. However, its analysis theoryand design method is far from completed. By means of specimen tests, theoreticalanlyses and numerical simulations, the mechanical performance of new type pier-girderrigid composite connections, new type compoiste girders with corrugated steel webs,and a new type steel-concrete connector without shear resistance were studied, and thecorresponding analycal models and design methoed were also developed. The mainresearch works and results obtained in this dissertation are as follows:(1) Specimens of rebar type and steel-cap type of composite rigid connections weretested under quasi-static loading, and the force transfer mechanism was studied. The testresults and numerical analysis show that the steel-cap type of composite rigidconnection has better crack resistance and bearing capacity than the traditional ones.The design method on the bearing capacity of the steel-cap type rigid connection wasthen proposed.(2) Four large-scale tests on composite box-girders with corrugated steel webswere performed, and the loading capacity, stiffness, cracking, strains and slips atsteel-concrete interface were studied. The laboratory test results and the parameterstudies show that the improved and new type girders have better mechanicalperformance than the traditional ones. The formulae on calculating the flexural strengthof composite box-girders with corrugated steel webs were also proposed.(3) Push-out tests on a new type of uplift-restricted and slip-permittedconnector under cyclic loading was performed, and the design method was alsoproposed. Comparison tests on composite truss girders under negative bending momentshow that the connectors without shear resistance can greatly increase the effectiveprestress and the cracking loading of concrete slabs.(4) Elastic partial differentia equation by considering local-released compositeactions was developed, and solutions under commonly used loading and boundaryconditions were derived. Comparision with the finite element analysis shows good accuracy of the theoretical formulus. Parametric study on continuous composite bridgeshows that application of the new type connectors in negative moment regions caneffectively release the tensile stress in concrete slabs, while the influence on structuralstiffness is minor.(5) Based on the traditional fiber model, a steel-concrete composite fiberbeam-column element by considering the slip effect on steel-concrete interface wasdeveloped, and the accurancy of the element was verified by comaprison with testresults.This dissertation is sponsored by National Natural Science Foundation of China(Grant No.51138007) and China National Science and Technology Ministry (Grant No.2011BAJ09B02). |
