DESIGN OF RECTANGULAR & T-BEAM  USING USD

1. SUBMITED BY-
MD.TIPU SULTAN 121116
SUBMITED TO
Dr. Md. Rejaul Karim(Ph.D)
DEPARTMENT OF CIVIL ENGINEERING
DUET

2. contents
Definition of T-Beam: slide 4
Effective flange width of T-Beam: slide 6
Strength Analysis: slide 9
Design of T-Beam: slide 12

3. DESIGN OF
RECTANGULAR Beam

4. Definition of Beam:
 Beam is the horizontal member of a structure,
carrying transverse load. Beam carry the Floor slab or
the roof slab. Bram transfer all the loads including its
self-weight to the columns or walls.

5. Definition of R.C.C Beam:
 R.C.CDue . Beam is to bendingtical moments
and shear. to the versubjected external load ,
bending compresses the top fibers of the beam
and elongates the bottom fibers. The strength of
R.C.C. beam depends on the compsite action of
concrete and steels

6. Rectangular beam design : singly &
doubly reinforced beam by USD
• Compressive Strength of Concrete, f‘c (3000-5000psi)
• Yield Strength of Steel, fy(40-60 grade)
• Spacing of Reinforcement------ (≥ maximum diameter of the
bars or 1-1.5in or 1.50 times
maximum size of aggregate)
• Concrete Cover------ ( for main bars 1in and stirrups 0.75 in)
• Beam Width
• Beam Depth, d
• Steel Area
Physical Factors
StrengthFactors

7. Important Considerations In Design
•Factored Loads (Generally 1.2 Dead Load +
1.6 Live Load which implies factored moment
Mu)
•Capacity Reduction Factors,
 ɸ = 0.9 for Bending in Reinforced
Beam;
= 0.75 for Shear and Tension.

8. Important Definitions
 Balanced Steel Ratio
 When due to same load tensile steel theoretically reach its
yield and concrete attains its ultimate strain 0.003.
 ρb = 0.85 * (f’c/fy) * [{0.003/0.003+(fy/Ey)}*d].
 Under Reinforced Beam
 When steel begin to yield even though concrete compressive
strain < 0.003.
 Steel ratio <<<< ρb.
 Failure with warning
 Over Reinforced Beam
 When steel begin to yield with concrete compressive failure.
 Steel ratio >>>> ρb.
 Sudden Failure.

9. Design Types of RCC Beams
 Singly Reinforced Beam
 Steel Only at Tension Zone i.e. below neutral zone.
 Design procedure is General Flexural Design.
 Generally Rectangular Beam.
 Design as when ɸMn ≥ Mu
Doubly Reinforced Beam
Steel in Compression as well as Tension Zone.
General Flexural Design both for top and bottom fibre.
Both Rectangular and T-beam.
Design as when ɸMn ≤ Mu.

10. Flexural Design Equations
Singly Reinforced Beam

11. Steel calculation
Client already deliver design
&demand.
Country code give to you load for this demand.
Such as BNBC/ACI.
Moment calculation
For S.S.B M= 𝑙𝜔2
/8
If Beam size consider by Architect &Compression zone not
perfect
To carry compression load you should be Design doubly
Reinforced Beam,

12. DESIGN OF
T- Beam

13. T BEAM DESIGN : SINGLY & DOUBLY : USD
10/26/2015 13

14. Definition of T-Beam:
 When slabs are monolithically casted with beams
in a positive moment zone, part of the slab act as a
part of the beam and resist the longitudinal
compression. The resulting section is T beam.
 The top of the T-shaped cross section serves as a
flange or compression member in resisting
compressive stresses.

15. Fig:T-Beam

16. Effective flange width of T-Beam:

19. Strength Analysis:

20. For case I:
Area of concrete
section, Area of
steel are known
a Calculation
Are of concrete section, Area of steel are
known

21. εc=0.003
d
c
0.85fc’
a/2
d-a/2
C
T
Strain Diagram Stress Diagram
As
hf
 
n n1 n2
n1 s sf y
f
n2 sf y
2
2
M M M
a
M A A f d
h
M A f d
 
 
   
 
 
  
 
For : fha 
10/26/2015 21
b
bw
And Nominal moment
capacity will be
Mn = Mn1+ Mn2
T- Beam Moment calculation

22. Design of T-Beam:

23. Moment or
loading is
given
Area of steel in
flange
Nominal moment

24. Moment For Web
Area of steel (Web)
Total area of steel

26. conclusion