ABSTRACT
Proof pile load tests are an important means to cope with uncertainties in the design and construction of pile foundations. In this chapter, the term load test refers to a static load test following specifications such as ASTM D1143, BS8004 (BSI, 1986), ISSMFE (1985), and PNAP 66 (Buildings Department, 2002). Load tests serve several purposes. Some of their functions include verification of design parameters (this is especially important if the geotechnical data are uncertain), establishment of the effects of construction methods on foundation capacities, and provision of data for the improvement of design methodologies in use and for research purposes (Passe et al., 1997; Zhang and Tang, 2002). In addition to these functions, savings may be derived from load tests (Hannigan et al., 1997; Passe et al., 1997). With load tests, lower factors of safety (FOS) or higher-strength parameters may be used. Hence, there are cost savings even when no changes in the design are made after the load tests. For example, the US Army Corps of Engineers (USACE) (1993), the American Association of State Highway and Transportation Officials (AASHTO) (1997), and Geotechnical Engineering Office (2006) recommend the use of different FOSs, depending on whether load tests are carried out or not to verify the design. The FOSs recommended by the USACE are shown in Table 10.1. The FOS under the usual load combination may be reduced from 3.0 for designs based on theoretical or empirical predictions to 2.0 for designs based on the same predictions that are verified by proof load tests.
