Question 2 a) Discuss the following types of steel with respect to structural design: i) Class 1 (plastic) ii) Class 2 (Compact) iii) Class 3 (Semi-compact) iv) Class 4 (Slender) AN (8) b) Determine the design tensile strength of the plate (200 x 100) mm connected to a 12 mm thick gussets, using 20 mm bolts shown below, if the yield and ultimate stress of the steel used are 250 MPa and 420 MPa respectively, fy= 250 MPa 40 30 30 200 30 30 40 40