The effects of externally applied reinforcement methodologies on globigerina limestone masonry walls

Abstract

This study focuses on the strengthening of globigerina limestone masonry walls by applying an external reinforcement to the surface of a masonry wall. The reinforcement methodology chosen for this study was a Textile Reinforced Mortar (TRM). This experimental program investigated the use of “Geogrid 120” a basalt mesh incorporated into a lime based mortar matrix, “GeoCalce F Antisismico”, which are both commercially available locally at "JMV Building solutions”. Eight half scale Globigerina limestone masonry walls where subjected to racking tests, replicating lateral movements and differential settlements, which are common events within the local masonry construction, particularly when subjected to additional storeys and alterations. This research compares the shear capacity and behaviour of unreinforced walls with wall specimens reinforced on both sides having different substrate surface finish, wall specimen reinforced on one side only and pre-damaged wall specimens which where subjected to reinforcement on either both sides or one side only. Through the analysis of video footage obtained during testing, crack propagation could be observed and this helped to better analyse the behaviour of each wall specimen. Patterns of displacement with time and the loads each wall specimen was subjected to helped to compare results of each wall specimen. The application of TRM in all wall specimens delayed failure of joint sliding which was the type of failure unreinforced walls experienced. Instead failure of reinforced wall specimens occurred through diagonal cracking and local crushing of Globigerina masonry units. Results indicate a large capability for structural enhancement of Globigerina limestone masonry walls, for both type of walls including as built walls, and for walls which where pre-damaged-repaired, where the largest shear strength enhancement recorded was for wall specimens reinforced on both sides. These registered a 173% increase in the shear strength when compared to a unreinforced wall specimen.