Appraisal of the Structural Adequacy of High-Rise Reinforced Concrete Domestic Buildings in Hong Kon

Environmental enhancement and the ‘aims of structural design’ We have received a plea from Mr R. P. Strauss of Stratford-upon-Avon to the effect that, as structural engineers, we should more specifically include ‘environmental enhancement’ as one of our declared ‘aims’: ’The IStructE document Aims of structural design proposes function, economy and safety as the desired objectives. In the first ‘cost v. maintenance-cost’ equations of economy, an additional ‘environmental enhancement factor’ should be considered. Environmental enhancement refers to the impact of the chosen structure on its users and beholders rather than, for example, the flood protection aspects of the Thames Barrier or the pollution reduction aspects of water treatment. Verulam

Since the mid 1950s, the Hong Kong Government has housed some 2.8 m people in approximately 1500 high-rise reinforced concrete buildings. Since the early 1980s the Government’s Housing Department has faced growing maintenance problems related in part to the low concrete strength encountered in some older blocks. R.A.M. Watkins and D.P. McNicholl

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