Prior to the concentric and eccentric load tests, tensile coupon tests
were conducted to measure the mechanical material properties.
Coupons were laser-cut from the same plates used for fabricating specimens.
For each steel type, a total of 5 tensile couponswere tested. Fig. 6
and Table 3 summarize the coupon test results. As shown in Fig. 6,
SM490 showed a stress–strain curve typical of ordinary steel. However,
HSA800 steels showed the properties typical of high-strength steels:
no sharp yield point, no distinct yield plateau, early strain-hardening,
high yield ratio of about 0.90, and reduced ductility. Because steel
overstrength was suitably assumed in designing specimens, the section
classification of Table 1 remained valid.