Study On Key Technology In Closure Of Long Multi-span Continuous Girder Bridge

Multi-span continuous girder bridge are widely used due to the stiffness of the bridge structure and smooth driving characteristics,.It is essential to take special research on multi-span continuous girder bridge as the domestic and foreign development of which such as bridge construction methods, the growing awareness of common disease problem are founded. In this paper, Analysis and simulation of such multi-span continuous bridge construction process and into the bridge state are made combine with the Yellow River Bridge project in Inner Mongolia. Some of the work has been done as follows:The development of multi-span continuous beam bridge are summarized, consider the cantilever construction methods of bridge, the difficulties often encountered in the process and bridges of common diseases. The pre-camber settings of bridge and the stress during the design closure sequences are considered, what more, the construction monitoring of the Yellow River bridge project in Inner Mongolia are made.The setting of the steel skeleton on the closure segment is the critical factor in construction. In this paper, a control group contain outlay-stiff skeleton and internal-stiff skeleton has been taken in the Yellow River bridge project in Inner Mongolia to calculation, analysis and compare the section properties with the internal force near the closure segment. And analysis about the influent of the system transformation are also been taken into considerations.The influence of the vertical temperature field for the multi-span continuous girder bridge are considered. The vertical temperature field which contain roof vertical temperature differences on roof, vertical temperature differences between roof and the webs and the vertical temperature differences along the section are simulated.Discussions are made to the internal force of the steel skeleton which combine with the vertical temperature differences. Conclusion that the influent of verti cal temperature load obviously can not be ignored are made.Based on the construction site for the bridge that the choices of the closure sequence、the tight construction period, we made the analysis about the closure sequences of the Yellow River bridge project in Inner Mongolia. Three different traditional sequences are provided to comprehensive comparison in various aspects, the best closure sequence are obtained, which provide some suggestions on the construction process.Because of different quantity span, long multi-span bridge is more hard to construction than usual continuous beam bridge; with more complex temperature influence,it is important to avoid the impact of the temperature effect on the bridge structure; what is more, reasonable selection of the closure sequence and optimizing the close process will successfully guarantee closure of the long multi-span bridge.