Calculation And Analysis For Long Span Cable-Stayed Bridge Structure

Based on practical projects and by applying large finite element software named MIDAS/CIVIL 2006, an integrated finite element model was builded up and the mechanics behavior of a long-span dual tower steel cable-stayed bridge were studied in this thesis.Firstly, development overview, structural systems and structural performance of modern cable-stayed bridge were introduced, then the current situation and future planning of the over-800m main span cable-stayed bridge structure were described. Then, according to the design requirements of the main bridge, a simulation on the girder, tower and cable were run and thus the full-bridge finite element model was established. Then according to this model, by adopting unknown load-factor method as a basis, the cable force was optimized as to achieve the desired goal so that the reasonable construction state can be determined by backward method. Then the construction phase analysis was conducted. The thesis then calculates in detail the structure stress of the bridge under loads, concentrating on calculating the stress and deformation of the bridge structure under the effect of dead loads, vehicle loads, temperature changes, wind loads and their combinations, then finds out the most adverse situations. The operational phase of the structure of the stability also was analyzed. At last, Seismic characteristics of structure were studied by the response spectrum analysis, draws the following conclusion that long-span cable-stayed bridge is a flexible structure, the girder is not strongly affected by the earthquake, but the main supporting tower, the piers and the temporary piers.Through analysis of the practical projects, the mechanics behavior and analyzing method of this kind of bridge were comprehensively understood.