University of Newcastle, Australia
A. HUIZER University of Calgary, Canada


An experimental study of the comparative ability of reinforced and prestressed hollow clay masonry walls to resist racking loads is described. Three walls 3000 mm high x 2500 mm long x 200 mm thick, were constructed from hollow clay units and Type S mortar. One wall was vertically reinforced and fully grouted. The second and third walls were left ungrouted, but post-tensioned with high strength Dywidag rods, one wall with prestress in the vertical direction only, the other with prestress applied both horizontally and vertically. Each wall was loaded monotonically with a horizontal racking force applied to a top corner of the wall. The overall response of each wall was monitored as well as surface strains in critical locations and progressive cracking. The results of the tests are reported, and the performance of the three wall types compared. It is shown that post-tensioning is potentially an extremely effective method of increasing the shear capacity of a wall.