Analysis Of The Influence Of Closure Parameter On Multi-span Prestressed Concrete Continuous Girder Bridge Completion State

With the development and use of the large displacement bearing and large deformation expansion joint, the prestressed concrete continuous beam bridge begins to develop towards large span and long connected continuous grider. Due to the increase of span’s length and number, multi-span prestressed continuous beam bridge completion state control becomes more and more difficult. As the key link part in the construction of prestressed concrete continuous beam bridge, closure segment construction has a significant impact on the finished bridge state. Therefore, it’s necessary to study on the parameters such as closure order and temperature which has influence on the state of bridge.This thesis takes the nine spans Dong-Ming Yellow River Bridge as the engineering background. The main research and results are as follows:(1)The research is based on investigating a large amount of documents, and then summarizes the closure parameters which have more influences on the completion state of multi-span prestressed concrete continuous beam bridge, and makes a brief introduction separately.(2)In this thesis,models for 11 different closure sequence and 3 kinds of closure temperature are established by finite element software Midas/civil 2012, and results are calculated respectively.(3)By comparing the upper and lower edge stress of bridge, it is found that the different closure order has little impact on stress and the distribution law of the main beam.By comparing the bridge line under different closure order,it is found that the bridge line is greatly influenced by the closure order. This research considers the construction difficulty, the construction period and other factors, and then selects a reasonable closure scheme.After compares the bridge line of some schemes among the 11 different schemes, the law of the bridge line influenced by closure order is obtained.(4)Affected by the change of different temperature, the bridge bearings vertical displacement may occur; this thesis determines an optimum closure temperature by compare the bearing vertical displacement. Finally, starting from the angle of reducing the maximum eccentric bending moment of bridge pier, this thesis illustrates the selection principle of closure temperature.Research shows that a reasonable closure order and temperature can ensure the final bridge main beam alignment.It can enable the stress distribution more reasonable and the construction period shorter. The bridge bearings maximum vertical displacement which influenced by temperature is small. At last, it can effectively reduce the maximum eccentric bending moment which the bridge pier supported.The analysis draws a general law about closure order and closure temperature,it has a certain reference value for the construction of similar bridges.