Small-scale testing of rehabilitated pile groups

The grouted, helical pier system (GHPS) is proposed as an example of a capacity improvement option for existing pile foundation groups. This paper explores the relative relationships between these geotechnical elements through the implementation of small-scale ground modification techniques causing increases in the axial capacity of the foundation, as measured as a function of load-based deflection. This initial set of tests indicates clear improvement of both piled and non-piled foundations through a variety of intervention methods both in terms of overall capacity and with respect to generating that capacity with smaller mobilization levels. The testing program also showed the likelihood for using some form of superposition as viable design methodology for predicting the performance of existing cast-in-place foundations that have been upgraded with ground-reinforcement and ground-improvement techniques.