Full-height piled bridge abutments constructed on soft clay

Pull-height piled bridge abutments constructed on soft clay are prone to la teral soil-structure interaction effects resulting from placement of the re tained fill, and associated deformation of the underlying soil. The interac tion increases lateral structural loading and displacement, and hence may r esult in unserviceable behaviour of the abutment or bridge deck. A series o f geotechnical centrifuge tests and finite element method analyses are repo rted, examining the effect of clay layer depth and the rate of embankment c onstruction. Agreement of data from the two methods is good, and the result s confirm the existence of established lateral soil-pile interaction in the clay layer. However, additional interaction effects associated with the re tained embankment material were also identified, causing a significant addi tional component of lateral loading on the structure, Such interaction incr eases bending moments in the piles, which are therefore of concern, Many ex isting empirical methods attempt to estimate these moments directly. Howeve r, it is argued that the moment loading is most logically viewed as a conse quence of the lateral loading components acting on the pile, and that a sim ple calculation based on this information is likely to be considerably more reliable.