Reliability-Based Design for Serviceability Limit State of Micropiles in Ontario Soils

This research is to develop a reliability-based design (RBD) for the serviceability limit state (SLS) of micropiles in Ontario soils according to international and national design codes. A database of 40 static tests conducted on full-scale micropiles is collected and applied in this study. First, a two-parameter hyperbolic model is used to curve fit the load-displacement curves of the micropiles. The hyperbolic parameters are identified through the least squares regression method. Second, the statistical properties including the mean value, standard deviation, and probability distributions of the model parameters are established. Copula theory is implemented to represent the dependence between the model parameters and influencing factors. Third, Monte Carlo simulations are applied to randomly generate the load-displacement curves of micropiles according to the hyperbolic model and the statistical properties of the model parameters. Last, a series of resistance factors are developed for RBD of SLS of micropiles in Ontario soils according to three design codes, including the American Association of State Highway and Transportation Officials, the National Building Code of Canada, and Canadian Highway Bridge Design Code.