a) Determine the elastic section modulus, S, plastic section modulus, Z, yield moment, M and the plastic moment M, of the cross-section shown below. What is the design moment for the beam cross-section. Assume 50 mm steel. 12 F, mm 0.75 mm 16 W t= 0.5 mm mm 1.0 AN, (7) b) To prevent local buckling occurring, it is necessary to limit the outstand/thickness ratios for flanges and depth/thickness ratios for webs of open sections. Column sections are classified as plastic, compact, semi-compact or slender, depending on their local buckling characteristics. Discuss the following: I. Plastic cross-section II. Compact cross-section