S - Kam Ng PhD Dissertation Final.pdf - Digital Repository of CCEE ...

193surrounding the pile and the consolidation of cohesive soils from pore water pressuredissipation induced by pile driving (Soderberg (1962) and Randolph et al. (1979)). Toaccount for the pile setup in design, the American Association of State Highway andTransportation Officials (AASHTO) (2010) suggests the use of dynamic tests involving timeconsuming pile restrikes and/or completing static load tests over a sufficient length of timealthough it is not feasible in practice to perform these tests. Furthermore, the measurednominal pile resistance obtained from the pile tests is assumed to be a single random variable(i.e., the uncertainties associated with pile resistance and pile setup estimations are assumedto be the same), and thus a single resistance factor is suggested in accordance with the Loadand Resistance Factor Design (LRFD) framework.Alternatively, pile setup can be accounted for using empirical methods (e.g., Skovand Denver (1988); Svinkin and Skov (2000)) or analysis-based semi-empirical methods asdescribed in Chapter 4, and the setup estimation using each approach has its own uncertainty.For example, based on extensive field evaluation, Chapter 4 concludes that setup can besatisfactorily estimated using the initial pile resistance obtained from a bearing graph(ultimate pile resistance versus hammer blow count) generated using Wave EquationAnalysis Program with SPT N-value based method (WEAP-SA) (Pile Dynamic, Inc (2005))and soil parameters as detailed in Eq. (5.1) without performing any restrikes or load tests.*( ) ( )+(5.1a)(5.1b)where,R setup = the pile setup resistance, kN or kips,R EOD = the initial pile resistance at EOD estimated using WEAP-SA, kN or kips,R t = the total nominal pile resistance at time (t), kN or kips;f c = consolidation factor (13.78 for using WEAP-SA in estimatingR EOD ),minute,