Safety analysis of the single-walled Steel Suspension Box Cofferdam during construction

The construction of the Steel Suspension Box Cofferdam (SSBC) is an important procedure for constructing the pile cap. In this paper, a safety analysis is carried out based on the construction of Chongqi Yangtze River bridge primary NO.2 pier SSBC. First, all calculation construction conditions and the corresponding loads are clarified. Second, with the use of ANSYS finite element analysis software, the corresponding finite element model is set up to evaluate its safety during construction. The results show: In the construction process, load and boundary conditions are constantly changing which makes the load transfer path and the mechanical characteristics of the various components also change. The load transfer pattern is hanging box- crane lifting point at first. Then it becomes hanging box - cantilever beam - steel pipe pile, and at last it changes into a dual transfer pattern of hanging box - cantilever beam - steel pipe pile and hanging box - sealing bottom concrete - steel pipe pile. The sealing concrete at the bottom has a strong binding effect on SSBC´s displacement condition. And the critical condition occurs when pumping out water at high tide level.