In-plane shear strength and damage fragility functions for partially-grouted reinforced masonry walls with bond-beam reinforcement

This paper presents a study on the in-plane shear response of partially-grouted reinforced masonry walls with bond-beam reinforcement. A database of 95 tests on partially-grouted walls made of concrete hollow blocks was compiled from experimental studies reported in the literature to characterize the capacity and damageability of walls subjected to in-plane lateral loading. The database has been used to evaluate the accuracy of existing design shear strength equations for partially-grouted walls. It is concluded that the shear strength expressions in the Masonry Standards Joint Committee (MSJC) code and Canadian standard are unconservative for partially-grouted walls. A modified equation based on the MSJC expression is proposed which better estimates the shear strength of this type of walls. Seismic fragility functions are also derived based on the experimental database to calculate the probability of experiencing moderate and severe damage in a partially-grouted wall for a given story-drift ratio deformation or normalized shear force demand. The resulting fragility functions show that the normalized shear demand is better correlated with the level of damage than the story-drift ratio. The first author Z. Zhang gratefully acknowledges the financial support provided by a Harbin Institute of Technology scholarship to conduct research as a visiting scholar at the University of Texas at Austin under the supervision of the second author J. Murcia-Delso. The co-authors C. Sandoval and G. Araya-Letelier are grateful for the funding provided by the Fondo de Fomento al Desarrollo Científico y Tecnológico (FONDEF) under Grant N° 17I10264 and the Fondo Nacional de Ciencia y Tecnología de Chile (FONDECYT Regular) through Grant No. 1181598.