A Practical and Safe Optimization Method for Temporary Cable Layout on the Upper Beam of Beam-Arch Composite Rigid Frame Bridge

Abstract

Long-span beam-arch composite rigid frame is a novel type of bridge structure. The safe operation of this bridge mainly depends on the bearing capacity of the root section of the upper beam. The upper beam is often constructed by the cantilever method using temporary cables (cable-stayed cantilever method). If the cable layout and cable forces are not reasonable, a plastic hinge will gradually form the root section of the upper beam under the unfavorable internal forces, posing a severe threat to the bridge safety. Therefore, this paper mainly aims to optimize the layout of temporary cables for the implementation of cable-stayed cantilever method. Firstly, the authors explored the essential function of the temporary cables on the upper beam. Next, four different methods for cable force optimization were compared, and the optimal method was identified for the upper beam of long-span beam-arch composite rigid frame bridge. Finally, 78 groups of temporary cable layouts were compared to find the optimal pattern. The results show that the essential function of the temporary cables on the upper beam is to reduce the negative bending moment on the root section of the upper beam at the completion state; the optimal method for cable force optimization is to tension the j-th temporary cable to the tensile stress on the lower edge of the upper beam; it is recommended to tension five temporary cables during the implementation of cable-stayed cantilever method. The research results provide new insights into the safety enhancement of beam-arch composite rigid frame bridges.

Mechanical System Evolution and Reasonable Structural Design Parameters of Long-Span Deck-Type Beam-Arch Composite Rigid Frame Bridge

“…The superstructure of Lijia Jialing River Bridge [18] adopts the beam-arch composite system. The main bridge is 785m long.…”