Loading Capacity Of Spatial Beam-Arch Composite Bridge And Bearing Joints

Spatial Beam-Arch Composite Bridge is a novel bridge system combining spatial structure with bridge. This system of high capacity and reasonable figuration makes the best of the members as the arch and the beam worked together perfectly. These bridges are complex for mechanical and tectonic consideration, since the dead loads are apparently lessened down thus the structural behaviors have greatly enhanced. Thus the problems of vibration and stability become very important and maybe control the bridge design. Besides, the load-bearing characteristics of the bearings of these bridges are instinctive from each other. Some bearings need to carry tensile loads and other bearings should bear shearing loads. Experiments are indispensable to these special bearings. Apart from that, deformation of bearings may impose influence on the carrying behavior of bridges and worth studying.The analysis methods of Spatial Beam-Arch Composite Bridge have been reviewed. The dynamic characteristics and stability of a steel Spatial Beam-Arch Composite Bridge– Bengbu Bridge of Tianjin Haihe-River has been analyzed. The mechanic behaviors of two bearings of the bridge are tested by experiments.The main research work is covered as follows:1) The finite element program ANSYS is adopted to establish a three-dimensional finite element model. The dynamic characteristics of the bridge are analyzed. The seismic responses are examined by spectrum analysis method as well as transient analysis method.2) Through the FEM model, the elastic stability and limiting bearing capacity of the bridge under different loads behavior are analyzed. The influence of nonlinearity (geometry nonlinearity and material nonlinearity) and the wind loadings on the composite bridge is focused on.3) The full-scale model of the bearings 2nd of abutment 1st and 6th of Bengbu Bridge is built and tested through exerting two load cases such as tension combined with shear, compression with shear.4) A full-scale model of the 3rd bearings of 2nd and 5th abutments of the Bridge was also established. A loading scheme combining ordinary jack with prestressing force was carried out and the static behavior of the bearings was analyzed. The full scale test reveals the rule of variation of vertical displacement and lateral displacement. A FEA model by ANSYS also verifies that the bearing has exhibited high load-carrying and deformation capacities. Some of the issues that need to be considered in the real bridge construction were also discussed.5) The static carrying behavior and limiting bearing capability of the bridge under different bearings'deformation (vertical deformation and horizontal deformation) are analyzed.