Orrcon Steel structural steel hot rolled plates and checker plate are supplied in accordance with AS/NZS 3678 thickness ranging from 3mm to 100mm and 2.1mm to 6mm for checker plate.Experimental research of replaceable Q345GJ steel shear Jul 01, 2017 · 4.6.4. Stiffener thickness. Specimen RSL-4, RSL-10 and RSL-6-2 have stiffener thickness of 3 mm, 4 mm and 6 mm, respectively. As can be seen from Fig. 27, the ultimate plastic overstrength V u /V p of RSL-10 and RSL-6-2 is almost the same.