| JFE Steel developed a new line of high-strength steel
products with a lower limit tensile strength of 550 N/mm²
for building frames using its advanced Super-OLAC (on
line accelerated cooling)accelerated cooling technology.
This product series currently consists of a steel plate,
“HBL385,” circular steel tube, “P-385,” and square
steel tube, “P Column G385.” These products realize
high strength and excellent earthquake resistance while
maintaining the weldability of the conventional steel.
The results of a test of members using the square tube
confirmed that the cumulative ductility factor of 30,
which is required in columns, can be sufficiently secured.
A rolled H-shape steel, “HBL-H385,” is also under
development. A design trial was carried out to investigate
the qualitative advantages and problems with these
products. The results showed that it is difficult to guarantee
the design criteria necessary to replace the beams
in all stories as story drift increases by more than 20%
due to reduced stiffness, but replacement of columns
presents no problems for practical use. A further expansion
of the applicable range is possible if designs are
prepared using these products from the initial stage. |
