CIVE 421 Other, Spring 2008

FACULTY OF ENGINEERING & ARCHITECTURE AMERICAN UNIVERSITY OF BEIRUT CE-421_ CONCRETE I 1 (2 HOURS), A 10, 2007 {OPEN BOOK) 1. (60%) & 25 e 4 20 é | =2.4 40 -=? | Longitudinal reinforcement = 16 T 25 Pf, = 280 kg/em’, fy = 4200 kp/em®, E,= 29 x 10* psi, and ¢y = 0.00207 1. Locate the plastic centroid. 2. Using a strain compatibility analysis, plot a 3-point nominal load-moment interaction diagram for the given column. Do not apply strength reduction and minimum eccentricity factors. The three points must be A (zero moment), B (balanced point), and C (zero load). Join the points by straight-line segments. IL. (40%) “fk jt F v7 Longitudinal reinforcement = 18 T 25 f= 280 kg/em’, f, = 4200 kg/cm’, E, = 29 x 10° psi, and e, = 0.00207 1. Use the ACI load-moment interaction diagrams to check the adequacy of the column whose section is shown above to carry at service an axial dead load of 80 Tons, an axial live load of 40 Tons, a moment about the major axis due to dead load of 40 Ton-m, and a moment about the major axis due to live load of 20 Ton-m. The column is part of a frame that is braced against sidesway. The effective length factor k is assumed to be |. The column is bent in single curvature about its major axis, The unsupported length is 5 m, and the moments at both ends of the column are equal. Hint: You have to check slenderness before you proceed Use Bresler's reciprocal load equation and ACT column strength interaction diagrams to compute the total factored moment about the minor axis which when applied simultaneously with the given axial load and major axis moment would cause failure of the column.