Structural Evaluation of Mortar or Sand Set Dimension Stone Pavers Using a Probability of Failure Approach

Structural failures of traditionally set mortar or sand set dimension stone pavers typically manifest as cracking and minor displacements as opposed to life-safety risks associated with similar structural failures of wall cladding panels or pedestal set pavers. Due to the different and reduced life-safety risks associated with traditionally set stone paver flexural failure, a proposed more liberal approach to structural analysis and design is presented in this paper that illustrates the benefits of explicitly evaluating the probability of failure of a particular paver installation rather than applying the traditional allowable stress design (safety factor) approach. This probability of failure approach provides the ability to quantitatively evaluate the influence of material properties and their variabilities. This paper presents the application of a proposed design and analysis approach for mortar or sand set pavers that is based on the probability of paver cracking under anticipated loading using the tested flexural strength and flexural strength variability of the stone and holding other variables constant (e.g., mortar strength and variability). The relative effect of tested stone flexural strength and variability on the probability of cracking is summarized in tables and figures that can be used to compare the risk of cracking for a stone type that meets ASTM requirements to one that does not. This paper is intended to provide a rational approach to the design of mortar and sand set paver systems for potential inclusion in the ASTM guide on installation of stone paving systems that is currently under development.