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

A 1.565m deep prestressed brickwork diaphragm wall, representing part of a full size highway bridge abutment, was tested in the laboratory under the combined action of a constant active earth pressure force and a gradually increased longitudinal had. At about 75% of the design ultimate load, decompression of the brickwork occurred and a horizontal crack formed along the bottom bed joint, propagating within approximately 140mm of the outer face of the front flange. With a further increase in the longitudinal load, the webs of the abutment cracked. Although this occurred fairly suddenly, a catastrophic form of collapse did not occur and the abutment was able to sustain a 29% increase in the applied load before the structure was judged unsafe and the test was stopped.Based on the load at which web cracking first occurred, a lower bound estimate of the principal tensile strength of the brickwork would be 0.3 N/mm2. Even though the horizontal shear stress in the brickwork during the test was in order of 5 N/mm2, there was no evidence of any bodily sliding of the abutment relative to the foundation.