Characteristics and Applications of 800MPA Highstrength Steel for Ultra High-Rise Build

by Do-Hwan Kim, Seung-Eun Lee, Jin-Ho Kim, Seng-Ho Yu

Publisher - RIST, POSCO Technical Research Laboratories, Pohang, South Korea

Category - General Novel

HSA800 is a new 800MPa high strength steel plate for building structures developed by POSCO and RIST in 2011 combining the advantages of SN and TMCP steels. It obtained the certification of Korean Industrial Standards (KS D 5994) in October 2011. It has upper and lower bounds for yield (Fy) and tensile (Fu) strength as of 650- 770MPa and 800-950MPa, respectively, with yield ratio (Fy/Fu) as of 0.85 below so as to make steel quality more reliable and enhance the seismic resistance of structures. Microalloys such as Nb, V and Ti affecting base metal’s grain refinement and thermo mechanical control process (TMCP) were added to increase yield and tensile strengths of the basic material. As made by TMCP, it has a good weldability without increasing carbon percentage. To evaluate the cost-effectiveness of the HSA800, two different analytical models of an ultra high-rise building artificially developed in accordance with typical tall building configurations were analyzed. The result shows that the high-strength steel model could save approximately 40% steel quantity compared to that of the normal strength steel model. HSA800 is being applied to the mega steel structural members of the Lotte World Tower, a first ultra high-rise building in South Korea having 555m height (124F). By reducing total steel quantity, it will also contribute to reduce CO2 emissions.

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