Application of reliability based design concepts to transmission line structure foundations. II

For pt.I see ibid., vol.6, no.1, p.352 (1991). A reliability-based-design methodology previously proposed by the authors for application to transmission line structure foundations is extended to laterally load drilled shafts. The results of a statistical analysis performed on four analytical models for predicting lateral load capacities of drilled shafts are discussed. A lognormal PDF is suggested for the ratio of measured to predicted ultimate capacity. It can be concluded that a particular foundation design methodology can only be used in practice with confidence after it has been calibrated against a large database of full-scale load tests. The statistical analysis also shows the economic impact of conducting more detailed subsurface investigations on the design of the foundations. An application example for the design of a straight drilled shaft embedded in homogeneous soil and subjected to an overturning moment load is presented