Assessment of settlement-based strain in masonry building facade due to tunneling

Abstract

Relative stiffness method (RSM) has been widely adopted to calculate the deflection ratios of masonry façades due to tunneling. However, comparisons with the existing 1 g physical model test, centrifuge tests and numerical studies reveal that the method would slightly overestimate the bending strains of masonry façades and severely underestimate the diagonal strains. An analytical Winkler solution is presented to investigate the effect of greenfield, soil conditions, facade geometry and eccentricity on the deflection characteristic of the deformation pattern and the modification factor of deflection ratio in RSM. Design charts accounting for the effect of the greenfield settlement profile are developed to better characterize the different facade settlement profiles and evaluate the deflection ratio based on RSM. In addition, an equation based on the deflection pattern represented by a simple beam subjected to a uniformly distributed load is proposed for determining the ratio of deflection ratio to the bending and diagonal strains. Lastly, existing field case studies are presented to validate the newly proposed equation combined with the modified RSM.