2. Pile load tests. Prior or during the construction of the foundation, a pile or pile group could be load tested in the field to determine its carrying capacity. Because of the uncertainties in the design of piles based on engineering analyses, pile load tests are common. However, the load test only determines the short-term load-deformation behavior of the pile. In addition, the zone of influence of a single pile will be much less than the zone of influence of the entire building.
Thus long-term settlement of the entire structure due to consolidation of the cohesive soil must still be evaluated. For example, the pile load test may demonstrate a high capacity, but once constructed,the structure experiences excessive settlement due to consolidation of clay layers located well below the pile tips.