Analysis of the Mechanical Behaviour of Double-wall Steel Boxed Cofferdam Structures

In recent years, double-wall steel boxed cofferdams with bottom structures have been applied in the construction of deep-water caps for bridges. However, their mechanical properties are affected by many factors. To elucidate the mechanics influencing such double-wall steel boxed cofferdam configurations, an analytical and computational model was proposed. Through the three-dimensional finite element software midas civil, calculations and analyses were executed on a steel boxed cofferdam design example from the 10# pier pile foundation of the Xinjiang Kalasuke Reservoir’s extra-large bridge and its platform construction. The alterations in mechanical states triggered by adjustments to the influential parameters, such as wall plate thickness, water injection height between double walls, and support rod spacing within the double walls of the steel boxed cofferdam, were discussed. Results show that, the optimal wall thickness for this cofferdam variant is between 5 and 6 mm, the controllable water injection height ranges from 3.4 m to 4.5 m, and consistently low-stress states occur across the bottom skeleton, secondary beam, and bottom plate throughout the construction process. The spacing between double-wall horizontal components greatly influences the stress and deformation of the inner and outer wall plates. The obtained conclusions provide a significantly reference value for the design theory and practical application of double-wall steel boxed cofferdam structures