At The End Of The Big Span Structure Constraints In The Process To The Temperature Of The Response Analysis

With the large number of prestressed concrete bridge construction, many problems appeared in the process of bridge construction and operation, The temperature effect of bridge structure caused by the construction of bigger harm. In bridge design and construction, we must need to consider the impact of temperature, in order to avoid the temperature stress to bridge construction safety。In this paper, combined with a large span prestressed concrete box girder bridge, It was originally designed hanging basket cantilelever construction, but construction is still maintaining the original design, while they make use of cast-in-place support section construction。So considering the sunlight radiation during the construction, because of the temperature inhomogeneous of beam body upper and lower, it will produce the temperature gradient distribution, so upper beam body elongation is larger than the lower beam, and cantilever end will have deflection tendency。At the same time, when we complete the pouring of the new construction concrete beam,we need to wait for the concrete intensity that reaches a certain index to the prestressed steel strand tensioning, yet tensioning prestressed steel strand between construction beam connection is still weak。In the initial set of concrete to the tensioning prestressed steel strand before a few days, because of the sunshine and temperature difference between day and night temperature, due to the role as well as the beam body at the bottom of the support joint action, it will cause the deformation coordination to the new and old construction segment, and the connected part of the construction of the new concrete beam may be destroyed.. Aiming at this problem, this article has done the related research and analysis, in order to find a solution to avoid potential safety problems of construction, ensure the bridge safety successfully closed, The following is what I do the main work:(1) Combined with the Ningbo port of Xiangshan highway bridge and the wiring engineering construction monitoring, in allusion to the construction of second, and make use of the sunshine radiation theory, through the solar radiation on box beam temperature field by Ansys finite element analysis, and the results compared with the relevant information provided in the most adverse temperature gradient curve。(2) According to the front of the temperature field data as well as the most adverse temperature gradient curve, at this time I add to these temperature effects data as the temperature load to the box beam finite element model, and I make the analysis of the continuous box beam of prestressed concrete structure under temperature effect between old and new beam section of the temperature stress and displacement of the bridge, and then draws the corresponding conclusion: namely, under the action of temperature, the old and the new beam between the temperature stress is larger and the beam body at the bottom of the support together, it will lead to a new beam deformation coordination, which may cause potential safety hazard。(3) Through the front of the results of the analysis, I have put forward the corresponding improvement measure, which we can watering water or laid batt to surface cooling that have been built in the beam body, so I can reduce the temperature gradient。 And then through the finite element analysis, so the temperature stress effect will be reduced。 Through the calculation of the results that is in line with expectations, and then I put forward the improvement measures in favor of lower temperature stress, which eliminates the potential safety problems of construction for the bridge construction, the right to provide a theoretical basis, in order to ensure the bridge closure smoothly。...