The Research On Geometric Nonlinearity And Stability Of Rigid Frame Bridge With High-pier And Large-span

In recent years, with the rapid development of the expressway of our country, large-span continuous rigid frame bridge with tall piers has been widely popularized and applied in bridge engineering. However, with the boost of the span and the piers, the structure is becoming more and more soft, the nonlinear effects and stability are become more and more important. Therefore, this article studied the following contents in detail.(1) The flexibility of the group pile foundation of large-span continuous rigid frame bridge affect the anti-push stiffness of the substructure of bridge directly. In order to get the real deformation and internal force and reasonably study the force performance of the combination system of t large-span continuous rigid frame bridge, it is necessary to consider the pile-soil interaction. This article utilize the finite element software Midascivil to establish the simulation model of the Shandianjiang Bridge of Chenzhou to analyze the impact of the bridge by force of large-span continuous rigid frame bridge on pile-soil interaction effects.(2) Based on Nonlinear FEM theory and closely combined with the engineering practice of large-span continuous rigid frame bridge with tall piers of the RuChen expressway—shandianjiang major bridge, we analyzed the geometric nonlinearity of the whole bridge by the software of MIDASCIVIL and the results show that the geometric nonlinearity of high pier is obvious, considering geometric nonlinear effect after the girder deflection increases. Discussing the curvature and height of piers on the Long-span Continuous Rigid Frame Bridge with geometric nonlinear effect, show that the nonlinear effect of Long-span Continuous Rigid Frame Bridge increases the with high pier and curvature’s increasing, and that high-pier can improve the stress of the rigid frame bridge pier, found the geometric nonlinear pier height less than40m bridge is not very obvious.(3) Using the great bridge software MIDAS_CIVIL, and taking the effects of geometric nonlinearity into consideration, we analyzed the autoinoculation stability of tall piers,the stability of cantilever construction and the construction of the whole bridge stability Discussing the influence of straining beam, initial eccentricity and defects on the high pier’s stability,according to the analysis above, we got that the straining beam can reduce the pier beam bottom moment and increase stability eigenvalue, the influence of initial eccentricity on the piers of the linear stability analysis is relatively small but the influence of the geometrical nonlinear stability of high pier is large, and that when the initial material defects was in the1/3of the high pier,the pier stability was the most disadvantageous. Analysising the cantilever construction stage’s geometric nonlinear stability of the large-span continuous rigid frame bridge with tall piers, show that the maximum cantilever construction stage was the most dangerous stage, geometric nonlinearity of Long-span Continuous Rigid Frame Bridge with high pier is obvious and the geometric nonlinearity decreases with cantilever length-increasing and that seting one straining beam in thel/2.of high pier beam can meet the construction requirements of the stability for the continuous rigid frame bridge with100m span and127.5m pier. Especially druing the cantilever construction,if the basket fall, the pier will occurred strength failure rather than stability wreck...