| The PC composite box-girder bridge with corrugated steel webs, which replaces traditional concrete webs with corrugated steel plates, is a newly developed structural form of bridge in China. This kind of bridge which has a beautiful form and a good mechanical behavior can also shorten construction period and be costing saving. The study on the structural performances of the box-girder bridge with corrugated steel webs in this paper is of theoretical significance and practical value in terms of practical engineering application.On basis of two group structural tests:the test on structural properties of a real variable cross-sectional PC composite box-girder bridge with corrugated steel webs; and the test on 12 shear connector models with 1:1 scale, the actual structural performance of box-girder bridge with corrugated steel webs is studied; Following the analytical solution and finite element method analysis, the structural performance of variable cross-sectional box-girder bridge with corrugated steel webs is also analyzed with regard to bending, shear, torsion, lateral force and the shear resisting ability of shear connector. The main work and achievements are as follows:1. The strain distribution along the sectional height of variable cross-sectional box-girder bridge with corrugated steel webs is studied on basis of the real bridge test and finite element analysis, quasi-plane section assumption is verified; The deflection distribution of variable cross-sectional box-girder bridge with corrugated steel webs along the axis of the bridge is studied under symmetrical loading and eccentric loading, which aims to analyze the influence of shear stiffness degradation of web on deflection of the structure.2. A formula for calculating shear stress of variable cross-sectional box-girder bridge with corrugated steel webs is derived; the results are checked with both the real bridge test and finite element analysis. The distribution of shear stress along the span, and the relationships of shear distribution between lining concrete and corrugated steel webs are investigated, the reasonable thickNess of the lining concrete is proposed.3. Distribution of the warping stress and strain of variable cross-sectional box-girder bridge with corrugated steel webs by torsion is analyzed, and a formula for torsion stiffness of variable cross-sectional box-girder bridge with corrugated steel webs is proposed, and the influence of sectional parameters and diaphragm on torsional stiffness of the structure is also studied for the practical design purposes.4. An analytical model for calculating transverse internal force in box-girder bridge with corrugated steel webs is put forward. The test and finite element analysis of the real box-girder bridge with corrugated steel webs verify the validity of the proposed model. By comparing with requirements of transverse design in Code for Bridges (JTG D62-2004), the result can give detail suggestions to insure the safety of transverse design of the structure.5. The push-out-test of the shear connector models of PC composite box-girder bridge with corrugated steel webs under both monotonic and cyclic loading is conducted, three kinds of forms (angle shear connector channel shear connector and Twin-PBL shear connector) are used, the mechanical properties of these three shear connectors are analyzed with regard to bearing mechanism, load-slip curves, bearing capacity, ductility and energy dissipation; Nonlinear finite element analysis of 21 entity models is done to study the influence of parametric variation on shear capacity of these three connectors. |
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