Proceedings of the International Conference on Steel and Aluminium Strucutres, ICSAS 91, Singapore 22-24 May 1991. The complete proceedings are available in three volumes: steel structures, aluminium structures and composite steel structures. The conference was organised by the Department of Civil Engineering, National University of Singapore sequel to the one held in Cardiff, UK in July 1987. It was co-sponsored by the International Association for Bridge and Structural Engineering, the Institution of Civil Engineers, the Institution of Engineers, Singapore, the Institution of Structural Engineers, the Steel Construction Institute, UK, the Singapore Structural Steel Society and the University of Wales College of Cardiff. The conference provided a forum to discuss recent advances and trends in the analysis, design and construction of all types of metal structures. This volume contains 18 of the papers presented at the conference. Invited Lectures on the state-of-the-art surveys have been provided by well-known experts in their respective fields. The coverage is extensive and topics include Bridges, Building Floor Systems, Concrete Filled Hollow Sections, Aluminium-concrete Systems, Composite Members to Earthquake Loading, etc.