Analysis of Mechanical Behavior in the Construction of Truss-stayed Bridge

Abstract

Cantilever installation is a commonly used method of construction in the superstructure construction of truss-stayed bridge. Considering construction safety, the mechanical behavior was analyzed for each phase of superstructure construction of the bridge. Based on building 3-D finite-element model of Kaziwan Bridge, girder’s geometric configuration, key section’s stress and stability of different construction phases were calculated, and the comparison of the calculation results and the measured results of vertical displacement, axis deviation, key section’s stress was carried out. The results show that (1) the measured values of vertical displacement are smaller than the calculation values due to actual stiffness of structure is larger than theory stiffness; (2) variation regularity between the theoretical value and the measured value of key section’s stress of the bridge agree pretty well in the construction, and structural mechanical behavior is the most disadvantageous from the maximal cantilever length phase to entire bridge closure phase; (3) the outward direction stability is obviously poor than the inward direction stability with cantilever length increasing and local outward loss stability is quite obvious on partial truss members.