S. W. GARRITY and T. G. GARWOOD Bolton Institute of Higher Education

A prestressed brickwork diaphragm wall, representing part of a full size highway bridge abutment, and a similarly constructed reaction wall of larger cross-section were built on a reinforced concrete base. Macalloy bars, anchored into the base, provided the prestressing force for each wall, the force being transmitted into the brickwork by precast concrete capping beams, A system of hydraulic rams was arranged to simulate both the longitudinal load applied to the abutment at carriageway level and the earth pressure forces acting on the back face. Under the simulated design service toad, there was no cracking in the brickwork. At the final stage in the test loading, when the bending moment and shear force resisted by the abutment were greater than those produced by the recommended design ultimate loads, there was no indication of impending shear or bending failure.