Plenary Lecture
| Plenary Lecture 4 | Design and Construction of Large Span Tubular Structures |
| Date / Time | 11 December 2019, Wednesday / 09:00 - 09:40 hrs |
| Venue | Lecture Theatre 6 |
| Speaker | J Y Richard Liew Department of Civil & Environmental Engineering, National University of Singapore, Kent Ridge, Singapore |
Abstract
Ultra-High strength concrete and high tensile steel are found to be attractive alternatives to normal strength materials for high-rise construction. In this paper, a design guide has been proposed for concrete filled steel tubular members based on an extension of EN1994-1-1 for concrete compressive strength up to 190N/mm2 and high tensile steel with yield strength up to 550N/mm2. More than 2200 test data collected from the literature on concrete filled steel tubes with normal and high strength materials have been analysed to formulate this design guide. This paper provides insights to the design guide sharing some of the expertise and knowledge for its applications to building construction. A comprehensive test program has been carried out to investigate the structural behaviour of tubular members infilled with high-strength concrete at ambient and elevated temperatures. More than 60 such tests were conducted including stub columns under concentric compression to assess the cross-sectional compressive resistance, beams under flexural loading to assess their moment resistance, slender tubular members under concentric and eccentric compression to assess the buckling resistance under compression and moment, and beam-columns members subject to standard ISO fire to assess their fire performance. The test specimens consisted of circular and rectangular concrete infilled tubes with steel grades from S355 to S690 and concrete grades from C50 to C190. Further tests were conducted to study the behaviour of these high strength steel and concrete materials at elevated temperatures. The effects of fibre types and dosage were investigated to improve the ductility of ultra-high strength concrete and to prevent spalling when exposed to fire. The test results were compared with analytical predictions to establish the validity of the proposed design method. Case studies are provided to highlight the applications and challenges encountered in construction. Novel solutions are suggested to overcome such problems for practical implementation.
Biography
Professor Richard Liew is currently the deputy head of research in the Department of Civil and Environmental Engineering at the National University of Singapore. He is a Professional Engineer in Singapore, a specialist professional engineer in protective security engineering and a UK chartered engineer. He is a Fellow of the Academy of Engineering Singapore, an Honorary Fellow and the Past President of Singapore Structural Steel Society. Prof Liew is world-renowned as an expert of advanced analysis of tall buildings and large-span structures with special focusses on robustness and hazard assessments including the effects due to fire, blast and impact loads. He has authored and co-authored six books and published over 400 technical papers. He received several research and design awards, including the 2017 best research paper prize from Institution of Structural Engineers, UK and the 2013 Structural Excellent Award from the Hong Kong Institute of Engineers. He is a key person responsible for the development of Singapore's practices for steel structures and steel-concrete composite structures.