Question

• 1) a)Determine the ratio of reinforcement that will result in a balanced condition for CMU . Given f’_m = 2500 psi and Grade 40 a,d 60 reinforcement.
• b) Determine the ratio of reinforcement that will result in a balanced condition for Brick masonry Given f’_m = 3000 psi and Grade 40 a,d 60 reinforcement.

Answer 1

Example: Balanced Condition Determine the ratio of reinforcement that will result in a balanced condition per UBC. Given: f. = 2000 psi and Grade 60 reinforcement F, = 0.33 f.=667 psi E. = 750 1. - 1500 ksi F, = 24 ksi for Grade 60 reinforcement E-29,000 ksi E, 29,000 – 19.3 E 1500 P. 19.3 19.3 + 24/0.667 2.x24/0.667 -]- -0.48%

Example: Reinforced Masonry Design a beam section for a moment equal to 370 kip-in. Prisms have been tested and is specified at 2000 psi. Use Grade 60 reinforcement and 8” CMU's. 1. From previous example, p, -1.48% 2. Estimate p to be slightly lower than , so steel will govern. A good estimate is p = 0.4% 3. Solve for k: *2 +2 pnk-2 pnzo 2 pn=2(0.004) (19.3)-0.154 k2 +0.154k-0.154=0 k.323 jul-k/3=0.892 4. Solve for ba? bd2-M/pils bd? (370 kip-in )/(0.004)(0.892 324 ksi) 4321 in)