Air-Blast Response of Axially Loaded Clay Brick Masonry Walls with and Without Reinforced Concrete Core

Abstract

Brick masonry is being replaced by other lightweight compatible materials in the walls, however, it is still being used. Almost all the old structures comprise of load-bearing as well as partition walls are of brick masonry. The blast response of such masonry elements is not well studied and understood. Unreinforced masonry (URM) walls usually perform poorly under extreme loadings due to their low tensile strength. Safety of the building structures with URM walls close to the sites such as ammunition depots, airports, and seaports which are vulnerable to the explosions is of concern. Recent ammonium nitrate explosion at the Beirut seaport (Lebanon) and the devastation that resulted from it is an eye-opener. More recently, the Russian invasion of Ukraine has increased this concern for existing infrastructure made of masonry. The present study aims to investigate the air-blast response of 6000 mm × 3040 mm × 350 mm (length × height × thickness) axially loaded clay brick masonry walls with and without reinforced concrete (RC) core using the commercial software, ABAQUS/Explicit-v.6.15. Two finite element models have been developed for this purpose. The first model is of clay brick masonry wall with the English bond arrangement. The second model is consisting of two wythes of walls, 110 mm thick each sandwiching 130 mm thick concrete core wall with grade M20 and M30 having nominal single curtain steel reinforcement. The models are subjected to the experimental blast peak overpressures available in the literature. For the accuracy of the results, the walls have been modeled using a detailed micro-modeling strategy. The concept of the masonry wall with the RC core has been taken from FEMA P-154 (2015), Rapid Visual Screening of Buildings for Potential Seismic Hazards - A Handbook. The damage model (Concrete Damage Plasticity) considering the plasticity of concrete and masonry in tension and compression has been utilized for the damage assessment of the walls. The effects of strain rate on the materials’ strength are also considered as per FIB MODEL CODE 2010 and UFC 3-340-02 (2008). Based on the results obtained, this study recommends the provisions for improving the response of the masonry walls under close-in explosion loading.