Simulation Analysis On The Construction Of The Main Arch Of Steel Truss Arch Bridge

Simulation computation of the main arch's construction control is the basis for the implementation of construction control. In the bridge construction phase, to determine the status of bridge construction appears to be more practical value, for its direct association with the construction technology and construction control. And ultimately the actual completed state of bridge is closely related to the construction state of bridge, so an in-depth study of the construction state of a bridge has a practical significance. This thesis takes the large-span steel truss arch bridge in the western hilly region for object, simulates, computes and analyses the construction process of the bridge's arch, mainly contains calculation analysis of buckle cable tension during the process of rib hoisting and stability analysis of rib hoisting under cross-bridge static wind load.According to the slanting pull and buckle construction features of nib hoisting of the steel truss arch bridge, the thesis put forward an idea of hoisting nib in place once, and educe two methods for solving the above-mentioned ideas of the installed buckle cable tension of nib and pre-camer of nib, which are the flexible - rigid support method and forward-backward iteration method.Based on the geometric properties and material properties of structure in design drawings, the thesis discusses the simulation of the structural components, the quality and the boundary conditions. And established three-dimensional finite element model of a large-span steel truss arch bridge construction process by the finite element software MIDAS.Before the construction of slanting pull and buckle cable of rib hoisting, to determine the buckle cable tension is important, which ensures construction and design line consistent as far as possible. In order to accurately calculate the buckle cable tension, the thesis uses the control points to control the displacement, and calculates and optimizes the buckle cable tension by the forward-backward iteration method introduced in chapter 2, and gets a group of proper buckle cable forces. Under these forces, the internal force value of the bar unit and displacement value of control points are both less than the allowable value of specification during the construction process of rib, thus, the method provides a theory basis for the construction of such bridges.Because the bridge is located in valley area where the wind environment is relatively poor, in order to ensure the cross-bridge stability of the arch in construction process, the thesis analyzes static wind stability under cross-bridge wind load during construction process through the finite element software. Through different load ways, comparative analysis of static wind stability of a large-span steel truss rib during construction was conduct, and the minimum stability factor is much larger than the requirement value of norms. In conclusion, horizontal static wind load has little effect on the stability of the steel truss arch during construction, and the steel truss arch bridge has good wind-resistant performance, which accord with requirements of wind-resistant design critetion.