Pre-camber Analysis for Hanging Cradle Construction of Qinhe Bridge

摘要

In order to ensure the safety of long-span continuous prestressed concrete girder bridge constructed by hanging cradle method, a pre-camber is always made to reduce shrinkage and creep in the process of post-operation, the late loss of pre-stressed, deformation produced by live load and so on. Combining with Qinhe Bridge, how to install the pre-camber is studied in this paper. The maximum pre-cambers and their locations of every span of Qinhe Bridge are determined by the method of standard JTG D62-2004 with the finite element analysis software MIDAS/CIVIL. The results show that the final pre-camber curves calculated by the method of standard JTG D62-2004 and quadratic parabolic method have cusps, which cannot meet the standard requirements for the smooth of the bridge. But the slop of the final pre-camber curve calculated by cosine curve at the maximum pre-cambers and the pier top is zero, and the slop of curve from pier top to the mid-span is small, which satisfy the standard requirements for the smooth of bridge. Therefore, the final pre-camber curve should be calculated by cosine curve.