The Study On Torsional Effect Of Highway Concrete Curved Box Girder Bridge

Structural curvature-the most essential difference between curved bridge and straight bridge in structure emphasizes bending-torsion coupling problem of curved bridge.Due to the thin-walled box beam adopted in concrete curved bridge, the warping torsion effect of the Beam should be taken into consideration to make a precise analysis. This paper studies the torsion effect of concrete curved box beam, prestressing effect and temperature effect on curved bridge.The main work and achievements are:1. Based on the interpolation function and the element-based strain energy, space beam element stiffness matrix which considers warping and includes seven degrees of freedom per node are derived.With the use of MATLAB software, the author works out space finite element program that consider the role of warping.2. The explicit formulation of box-section torsion parameters is derived, and the calculation of box-section torsion parameters is programmed. Based on the above procedures, the warpage attenuation factor kl, diaphragm, curvature effect on warping torsion are analyzed.3. The wrong concepts of prestress on bending beam torsion effect are corrected. In different prestressed tendon arrangement, torsion effect of the prestress on simply supported curved beam and continuous curved beam is studied.4. Through solid models, internal forces and stresses of concrete curved box girder in different curve radius under line mode gradient temperature and exponential curve mode gradient temperature are analyzed and compared.5. Sunshine thermal curve is derived based on the simulation of concrete curved box girder transient temperature field. It turns out that the curve is almost consistent with the exponential curve in code for design on reinforced and prestressed concrete structure of railway bridge and culvert. Also, the author conducts a time history analysis of the transient temperature field on the curved box girder bridge support reaction.