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Reliability-based design (RBD) can overcome some limitations and ambiguities in the partial factor design approach found in Eurocode 7 (EC7) and the load and resistance factor design (LRFD) method used in North America. The aim of this study is to show how RBD via the first-order reliability method (FORM) can complement LRFD and EC7 codes. Three geotechnical engineering examples are used to demonstrate that RBD-via-FORM can provide guidance to the partial factor design approach in situations with load-resistance duality, shear strength parameters with context-dependent sensitivities, parameters not covered in design codes, cross-correlated parameters, and designs aimed at a target reliability or failure probability. Insights from RBD-via-FORM are presented. The differences and similarities between the design points in RBD, partial factor, and LRFD methods are explained. Comparisons are made with Monte Carlo simulations, the mean-value first-order second-moment method, and the Bathurst–Javankhoshdel closed-form reliability index solution which is restricted to simple linear limit state performance functions with lognormally distributed load and resistance terms and bias factors. It is suggested that RBD-via-FORM can be conducted in tandem with EC7 and LRFD methods in order to overcome limitations and ambiguities which sometimes arise using these methods. [ABSTRACT FROM AUTHOR]

The focus of this paper is on quantitative evaluation of four different methods that use closed-form equations to calculate the nominal load in steel grid-reinforced soil walls under operational (end of construction) conditions. The four methods are the Coherent Gravity Method used in the UK, the AASHTO Simplified Method (USA), the PWRC Method used in Japan and the Simplified Stiffness Method. The accuracy of the methods is quantified based on analysis of bias statistics where bias is the ratio of measured to predicted (nominal) load. A large database of 113 measured reinforcement loads collected from 11 instrumented field walls is used in the study. For walls constructed with frictional soils, the Coherent Gravity Method and PWRC Method were the least accurate. The AASHTO Simplified Method demonstrated better accuracy and the Simplified Stiffness Method was the most accurate of all methods examined. The Coherent Gravity Method and the updated Simplified Stiffness Method for steel grid walls in the current study have the advantage that they can be used with soils that have a dependable soil cohesive strength component. However, the accuracy of the Simplified Stiffness Method was much better for all soil types based on bias analyses. [ABSTRACT FROM AUTHOR]

Glass beads were coated with a mixture of mechanoluminescent (ML) paint and epoxy resin in order to visualize particle-level force distribution through an analog granular material. SEM observation and X-ray CT scanning was used to verify that the application of the ML coating on the glass beads was uniform. Load tests were conducted on single columns of coated glass particles to equate luminance to diametrical forces transmitted through the particles and particle contacts. The relationship between loading (force) rate during elastic loading of the coated particles and luminance was determined using a column of beads placed in an axial loading device. Coated glass particles were placed in a transparent plane strain container and subjected to biaxial loading to visualize the load transmission through the analog granular material placed in a regular packing. The anisotropy of chains of load transmission during loading was detectable using this test arrangement. The sum of contact forces at the top container boundary deduced from particle luminance is shown to be in agreement with applied boundary loads. This novel technique holds promise as an alternative approach to visualize and measure load transmission through idealized 2D assemblies of granular material. [ABSTRACT FROM AUTHOR]