ABSTRACT
Steel with a specified minimum tensile strength of 400 MPa or 490 MPa are widely used for steel construction in Japan. Innovation in steel manufacturing technology has led to the development of ultra-high-strength structural steels with tensile strength near 1000 MPa. For example, H-SA700 is a new grade of steel with a minimum tensile strength of 780 MPa (Yoshida et al., (2009)). This steel was intended for wide use in building structures, so its manufacturing technology was innovated to CO2 output and save more rare alloying elements. The reduced usage of alloying elements is favorable to recyclability of steel. The weld material with matching strength is not yet available for
the column pattern and evaluated the flexural performance of the column. Cyclic loading tests demonstrated that the built-up column using H-SA700 steel exhibit very high strength, develop a long yielding zone near the column end, and that its flexural behavior may be evaluated using the assumption that plane sections remain plane.
