Research On The Behavior Of Thin-walled Box Girder With Initial Flaw

Now, the thin-plate structure is widely applied to modern projects, especially to bridge structures (including the outsized span steel hanging bridges, the large span cable stayed bridges, the continuous girder bridges and simple supported girder bridges with medium or small span). So over resent 40 years and through world-wide bridge constructions, Besides, with extensive use of the box-girder bridge throughout the country, the reports about engineered plagues are increasing and the crucial problems are as follows:The emergence of a variety of cracks;the experimental model and finite element numerical analysis confirmed the density of pore filling the impact of stress on the cross-section. Post-tensioned prestressed channel weakened section of the main beam, thus the entire structure of the impact of the stress distribution.In this paper, the experimental model and finite element numerical analysis confirmed the density of pore filling the impact of stress on the cross-section, Then taking Chongqing Soil and Water Bridge for an example and using ANSYS (a analysis software for a finite element analysis on those large structures), this paper sets up models of plane analyzing and three dimensional analyzing, and does the numerical analysis on each construction segment in part 0～2#of the main box-girder(single box in single room) of this bridge, by which the pre-stressed ducts'influences on the load-bearing characteristics of P.C. bridge's section is turn out to be assignable, at the same time, we have simulated experiments of cracking and grouting by the finite element software, and the influences from cracking and grouting on carrying capacity of the bridge are affirmed. and show prospects of the development trend of researches on the load-bearing characteristics of P.C. bridge and its cracking causes, and make objectives for further research works.The researches in my paper will be performed regarding the three aspects as follows:1. Is in the milk through the test simulation and the finite element software Ansys numerical simulation passageway to the box beam bridge structure behavior influence, and draws the corresponding conclusion.2. By the second-round development tool of ANSYS and parameterized ANSYS designing language, the three dimensional solid model of 0～2# section of the main box girder of Chongqing Soil and Water Bridge should be set up because it will be used for the space and three-dimensional analysis under constructions and the completion of bridge. Simulation of duct-grouting and other construction processes are crucial, by this we can analyze and understand the distribution conditions of stresses on the box-girder's sections with pre-stressed ducts during the whole project.3. Considering the following factors such as whether the duct-effects exist or not, compact or incompact grouting or not, and according to data from ANSYS three-dimensional numerical analysis, the stress distribution of the typical sections of the main box girder under the special engineering status should take some comparison and analysis, by this we can do researches on the post-tensioning pre-stressed ducts'influences on the load-bearing characteristics of the box-girder's sections of the P.C. bridge.