Stability of a large-span continuous rigid frame bridge with high pier

In this paper, based on the actual project Liangshui Bridge, the finite element analysis software MIDAS Civil is used to establish the bridge construction stage model and the completed bridge model. First, the models of each construction stage from block 0 to block 17 (maximum cantilever state) are established. Three working conditions are considered: symmetrical construction; asymmetric construction of one side hanging basket falling; asymmetric construction of one side pouring concrete. The stability coefficient is extracted and compared with the theoretical value calculated by the simplified model of mechanics of materials. The ratio of the theoretical value to the calculated value of the model changes with the load on the top of the pier. Secondly, the model of bridge completion stage is established. Four working conditions are considered: full load of side span, full load of mid span, full load of side span and mid span, full load of the whole bridge. Through stability analysis, the most unfavorable working condition is determined. Under this condition, change the pier height, carry out the stability analysis, and get the curve of bridge stability coefficient with the pier height. By analyzing the stability of the continuous rigid frame bridge with high piers, this paper obtains the law that the ratio of the calculated value of the simplified model of mechanics of materials to the calculated value of the finite element model changes with the load on the top of the pier, and the law that the height of the pier affects the stability coefficient of the bridge, which is helpful to give the correct stability evaluation of the bridge at the corresponding stage, and provides the scientific basis for the design and construction of the actual project.