Probabilistic models for the initiation of seismic soil liquefaction

A Bayesian framework for probabilistic assessment of the initiation of seismic soil liquefaction is described, A database, consisting of post-earthquake field observations of soil performance, in conjunction with in situ "index" test results is used for the development of probabilistically-based seismic soil liquefaction initiation correlations. The proposed stochastic model allows full and consistent representation of all relevant uncertainties. including (a) measurement/estimation errors, (b) model imperfection, (c) statistical uncertainty, and (d) inherent variabilities. Different sets of probabilistic liquefaction boundary curves are developed for the seismic soil liquefaction initiation hazard problem, representing various sources of uncertainty that are intrinsic to the problem. The resulting correlations represent a significant improvement over prior efforts, producing predictive relationships with enhanced accuracy and greatly reduced overall model uncertainty

Assessment of the Partial Safety Factor Related to Resistance Model Uncertainties in 2D NLFEAs of R.C. Systems

This work estimates the partial safety factor corresponding to the resistance model uncertainties in non-linear finite element method analyses (NLFEAs) of reinforced concrete structures considering various structural typologies with different behaviours and failure modes (i.e., walls, deep beams, panels). The comparison between the two-dimensional NLFE structural model results and the experimental outcomes is carried out considering the possible solution strategies available to describe the mechanical behaviour of reinforced concrete members in different software codes. Several NLFE structural models are defined for each experimental test in order to investigate the resistance model uncertainty. Then, a consistent treatment of the resistance model uncertainties is proposed following a Bayesian approach identifying the mean value and the coefficient of variation of the resistance model uncertainties. Finally, in agreement with the safety formats for NLFEAs of reinforced concrete structures, the partial safety factor is calibrated