The application of continuous surface wave testing for settlement analysis with reference to a full-scale load test for a bridge at Pont Melin, Wales, UK

Abstract

The presence of a significant thickness of soft silts beneath the site of a proposed new road bridge caused concerns over the suitability of shallow foundations. Despite extensive conventional ground investigations, it was not possible to obtain reliable stiffness data, and so a full-scale, fully instrumented load test was undertaken to better determine ground stiffness. The data obtained was used in conjunction with sophisticated numerical analysis to demonstrate that the settlement of shallow foundations would be acceptable. Following completion of the bridge construction, Continuous Surface Wave testing was undertaken and a range of simple non-linear elastic settlement analyses conducted to model the behaviour of the load test. Through these analyses this paper demonstrates the benefit of using continuous surface wave ground stiffness testing in conjunction with simple analysis methods. It underlines the importance of obtaining high-quality stiffness data to accurately predict settlement of shallow foundations.