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).

T Beams

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

-

Design Steps for T-beam