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By Dr. Attaullah Shah Swedish College of Engineering and Technology Wah Cantt. Reinforced Concrete Design-4 Design of T beams. Quick 30 minutes- Open Book Quiz. Compare WSD and USD methods. (5 min) - PowerPoint PPT Presentation
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By
Dr. Attaullah Shah
Swedish College of Engineering and Technology Wah Cantt.
Reinforced Concrete Design-4
Design of T beams
Quick 30 minutes- Open Book Quiz
− Compare WSD and USD methods. (5 min)
− Design a simply supported singly reinforced concrete beam of span 15 ft having a superimposed dead load of 1K/ft and live load of 1.5K/ft. fc’ = 4000 psi and fy= 60000psi (15min)
− Determine the moment capacity of doubly reinforced beam of size 12inx18in having 6#8 bars in the bottom and 2#8 bars at the top. Use the above material stresses. (10min).
Case 1: Compression area in Flange a<t
− If the depth of equivalent stress block is equal or less than flange depth, the beam may be designed as rectangular beam.
− In such case
− Nominal moment Capacity
− If the thickness of a > t, then T beam analysis will be required
Case 1: Compression area in web a>t
− The tensile force in steel T is resisted by two components one C1corresponding to A1 and other C2 corresponding to A2
Compression
− Area of steel corresponding to compression in Flange is given as
− The nominal resisting moment by flange is given as
− The remaining steel area ( As-Asf) is compensated by the compression in web.
− The additional resisting moment is given as
− The total nominal resisting moment is given as:
−
Maximum and Minimum Steel- For Case
- The area of steel reinforcement As is given as
- The balanced steel ratio is given as
- The balanced steel ratio is given as (87000/(87000+fy))
- For Case 2
-