Experimental study of the flexural strength of URM (Brick) walls

Unreinforced (brick) masonry (URM) construction in South Australia follows local regulations (SA Housing Code, 1996) which, in some circumstances, permit the construction of 4m tall single leaf brick masonry walls even though they do not comply with the slenderness limits given in AS3700 (SA, 1998). Because "none of them have ever fallen down" is often used to justify their continued use. Of course, another possible reason that they have never failed is that they have never been subjected to their full "design load". It was the aim of this project to establish the actual strength for several of the "deemed-to-comply" wall details given in the South Australian Housing Code. The experimental values were compared to the design capacity values obtained using AS3700 in order to verify whether the walls satisfied the masonry structures code. The tests were performed in Adelaide University's Chapman Structures Lab in the Department of Civil and Environmental Engineering. The experimental walls all exhibited strengths in excess of the con'esponding AS 3700 design capacities by factors of between 1.8 and 3.7, suggesting that the code estimated strength values are reasonably conservative. While the calculated design strength for an internal 4m tall single leaf non load-bearing brick wall is less than the design earthquake load for Adelaide, the experimentally determined strength was found to be sufficient (by a factor of between 1.6 and 3.3). Under no conditions was the 4m tall wall found to be adequate as an external wall or cladding to resist wind loads or earthquake forces without additional support.Michael Griffit