Dimension stone design – kerf anchorage in limestone and marble

Abstract

This paper describes a study on kerf anchorage behaviour in three types of stones. Two limestone and various marble specimens were submitted to a series of tests – namely standard absorption, bulk specific gravity and flexural strength tests – to determine their physical and mechanical properties. The paper focuses on the results of tests carried out according to the ASTM Standard Test Method for Strength of Individual Stone Anchorages in Dimension Stone. These tests were performed on a stiff rail continuous anchorage system on both the front and rear kerf legs. Stress analysis and finite element method calculations were the basis for the proposed semi-empirical formula to estimate this anchorage system's breaking load under the above-mentioned conditions. Through a general but practical example, it is shown that a design focused on the bending strength of stone panels, to the detriment of the kerf anchorage, is an unsafe and yet common practice. The paper emphasises that designing stone cladding systems with continuous kerf must take into account different effects in order to evaluate the effective stress in the critical region of the kerf geometry. Separate stress concentration factors are proposed to account for the kerf geometry and the specimens' specific properties.