Structural Performance of 800 MPa High-Strength Steel Members and Application to Highrise and Mega Building Structures

Abstract

The use of high-strength steels in construction of highrise and mega building structures can bring about many technological advantages from fabrication to erection. However, key design criteria such as local and lateral stability in current steel design specifications were developed based on tests of ordinary steels which have stress-strain characteristics very different from that of high strength steels. A series of tests on 800 MPa tensile strength steel (HSA800) members are summarized in this paper which were conducted to investigate the appropriateness of extrapolating current ordinary-steel based design criteria to high strength steels. 800 MPa I-shape beam specimens designed according to flange local buckling (FLB) criteria of the AISC Specification developed a sufficient strength for elastic design and a marginal rotation capacity for plastic design. It is shown that, without introducing distinct and significant yield plateau to the stress-strain property of high-strength steel, it is inherently difficult to achieve a high rotation capacity even if all the current stability limits are met. 800 MPa I-shape beam specimens with both low and high warping rigidity exhibited sufficient lateral torsional buckling (LTB) strength. HSA800 short-column specimens with various edge restraint exhibited sufficient local buckling strength under uniform compression and generally outperformed ordinary steel specimens. The experimental P-M strength was much higher than the AISC nominal P-M strength. The measured residual stresses indicated that the impact of residual stress on inelastic buckling of high-strength steel is less. Cyclic seismic test results showed that HSA800 members have the potential to be used as non-ductile members or members with limited ductility demand in seismic load resisting systems. Finally, recent applications of 800 MPa high strength steel to highrise and mega building structures in Korea are briefly presented.

Structural behaviour of cold-formed S700 high strength steel tubular members after exposure to fire

“…Figure1.1 depicts typical engineering applications of HSS, including the Lotte World Tower in Seoul, which used HAS800 HSS as construction material(Lee 2017), the Cowboy Stadium in Texas, USA, which adopted S460 HSS for the chords of trusses(Bjorhovde 2010), the Nesenbachtalbrücke in Germany, a 572 m long bridge, which used S690QL1 HSS to produce reduced sizes of structural members, to satisfy architectural requirements regarding aesthetics and functionality(Collin and Johansson 2006).Different from the open section, the effective mass distribution of the tubular section provides it expectational flexural stiffness and torsional rigidity, which exhibits excellent structural performance in bending and twisting. Structural tubular hollow sections with aesthetic appearance and excellent mechanical performance have been applied as structural components in civil engineering since the 1970s(Hu 2019).…”