Masonry crack damage: its origins, diagnosis, philosophy and a basis for repair

This paper deals with the repair of brickwork and masonry walls that have c racked as a result of ground movement. It outlines work in this field over the last 60 years, identifying the options of repairing the foundation or i ncreasing the ductility of the brittle structure. Practice has been to unde rpin or otherwise strengthen the foundation but this paper examines the pot ential to modify the behaviour of the masonry itself by introducing reinfor cement. A study of four building facades, verified by a programme of labora tory tests, leads to the conclusion that if the ductility of existing mason ry can be improved then the need to underpin will be reduced. This is of pa rticular relevance to non-invasive restoration of historic buildings but al so offers an economic repair to more routine structures. The paper conclude s that localized reinforcement of masonry walls can significantly increase their tolerance to foundation movement.