T.G. HUGHES and R.J. HARVEY
University of Wales, Cardiff
Strains measured in a highly stressed internal wall of a nine storey structural brick masonry tower block are reported over a period of some 6000 d. Both mechanical and vibrating wire acoustic gauges were installed during the initial construction period. The gauges were in a basement room on wall panels which form part of the structure of a lift and staircase shaft; both methods of strain detection operated reliably over the test period. The greatest part of the axial movement detected occurred within 3000d of construction, however lateral strains are still developing in the masonry after sixteen years. The axial strains developed principally in the mortar joint, whereas the masonry units themselves underwent lateral expansion. Measured axial strains are compared with those given by existing methods of prediction.