M. E. PHIPPS and T. I. MONTAGUE University of Manchester, Institute of Science and Technology


The paper describes full scale tests on four concrete blockwork diaphragm walls, twelve square hollow section beams and seven I section beams. Two of the walls were 4m high x 3m long with metal ties to connect the webs to the leaves and damp proof membranes incorporated at the web-leaf interfaces on one side. Both walls were tested as unprestressed, or plain, propped cantilevers to simulate walls in a building. The other walls were 3m long x 3m high and were built with the cross ribs bonded into the leaves, in one case using standard blocks and in the other case using quoin blocks. These walls were prestressed with an unbonded post-tensioning system and were tested as free cantilevers. They were intended to simulate prestressed concrete blockwork diaphragm walls acting as retaining walls. Later, all four walls were prestressed to different levels and losses were measured for over a year. The hollow section beams 4- 5m long and 440mm wide and deep were post-tensioned with unbonded tendons and tested in bending up to ultimate load. The I beams 3-Om long x 670mm to 780mm wide x 440mm deep with various bonding patterns, with and without metal ties and under different levels of prestress were used for shear tests. The results have led to detailed and comprehensive design rules which are being published as Design Guides.