Design Parametric Analysis And Research Of Multi-span Continuous Rigid Frame Bridge

With the rapid development of highway, driving speed increased and driving comfort has been promoted a very important position.As possible as to increase the span of the bridge, which is conducive to high-speed traffic and can ensure the comfort of travel,became an important factor of selecting the type of bridge. In this case, the multi-span continuous rigid frame bridge with the advantage of no expansion joint, driving comfort, no support, convenient construction, long span and so on, to be the excellent type of bridge in highway. With the multi-span continuous rigid frame bridge appeared, the height-span ratio of the bridge is avriable, but the reasonable ratio has great influence on the force condition of the structure.In addition, continuous rigid frame bridge is not statically structure, temperature change and concrete shrinkage and creep will lead to additional internal forces of the larger structure, need to design flexible and smaller stiffness pier to reduce the the derivative force result from various factors of the structure, and the key point to the design of bridge is a reasonable ratio of beam stiffness to pier stiffness.In this discourse, with the background of a existing bridge, to establish finite element model of a four-span continuous rigid frame bridge with the process of the construction, considering the constant load, the annual temperature difference, day sunshine temperature difference,the six types of load conditions, in different conditions under the load stress and key section force and the comparison of the key section in the internal force and stress value of constant load in the same section of this percentage to determine the structure stress influence degree, the comprehensive analysis and comparison of the girder will depth-span ratio, pier beam stiffness ratio as two important design parameters. Then, by changing the depth-span ratio and girder beams than the two piers stiffness of the design parameters, structure in constant load, temperature changes in temperature, sunshine and three load conditions, the stress analysis of the whole bridge in H/teams in each section of the internal stress of the key and the change rule and bridge in H/L increases the critical section and change rules of internal stress.Finally, based on parametric analysis,took optimization theory, establish the objective function, using the grid search method for finding the optimal height-span ratio, and compared the optimized bridge and the original bridge...