A numerical model for predicting the bending strength of Larssen steel sheet piles

Abstract

Larssen piles are U-shaped in cross-section and are connected together by sliding joints to form quay walls, cofferdams and other types of retaining walls. Since the sliding joints are located along the centreline of the pile wall, slippage of one pile relative to another can lead to a 70% reduction in elastic bending strength. This slippage can be partially prevented by installing the piles in pairs, with the interlocks ‘crimped’ to prevent inter-pile movement. However, like non-crimped piles, the bending strength is difficult to predict since slip still can occur between the crimped pile pairs. This paper presents a numerical model for predicting the bending stresses and crimp forces in crimped pairs of Larssen piles. Tests are also reported on one-sixth scale pile walls constructed from extruded aluminium Larssen piles, with the results compared with those from the numerical model. Stress predictions from the numerical model are shown to be in close agreement with the experimental results, and can be used to economise on the crimping necessary to achieve the full composite bending strength.