Answer Happy

a) Consider the rectangular column shape as shown in Figure 1. Draw a interaction diagrams of the column by taking account three cases (i) the contribution of concrete only; (ii) Concrete and steel bar A 2 (bottom) and (iii) Concrete plus steel bar A2 (bottom) plus bar Ası (top). At what values of Axial and Moment that the column will undergo balanced failure for all cases. Calculate the load eccentricity at balanced failure. The material parameters are given as following: Compressive stress of concrete fcu = 40 MPa. Concrete strain at failure = 0.0035 Elastic modulus of concrete = 30,000 MPa Elastic modulus of steel bar = 200,000 MPa b) At what load does the steel bar for case (A22 only) become active and start to yield. c) Explain and comment on the failure mode of the column that you can deduce from the interaction diagrams for all three cases. Asi = 402 mm (total for both-bars) 650 50 A2 = 628 mm (total for both-bars) 250 (Figure 1)