Since the mid-l950s, the Hong Kong Government has housed some 2.8M people in approximately 1500 high-rise, reinforced concrete buildings. By the early 1980s, the Government’s Housing Department was facing growing maintenance problems in the older blocks. These difficulties arose in part from the common problems of reinforcement corrosion and spalling which are now being faced worldwide, and also because of generally low and extremely variable concrete strengths. This paper describes, firstly, how these defects were identified and how priorities for further action were
established through the development of ranking systems. It goes on to discuss the techniques utilised in assessing the nature and extent of the defects, including visual survey and testing programmes, and the development of a structural appraisal methodology. Finally, the ways in which the defects are now being redressed, and the repair and strengthening methods being used, are outlined.
D.P. McNicholl, P.R. Ainsworth, M.V. Harley, B.J. Stubbings and R.A. Watkins