Rectangular beam design by WSD method (singly & doubly reinforcement)
Design of rectangular & t beam using usd
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Transcript of Design of rectangular & t beam using usd
DESIGN OF RECTANGULAR & T-BEAM USING USD
SUBMITED BY- MD.TIPU SULTAN 121116
SUBMITED TO Dr. Md. Rejaul Karim(Ph.D)
DEPARTMENT OF CIVIL ENGINEERING DUET
contents
Definition of T-Beam: slide 4Effective flange width of T-Beam: slide 6Strength Analysis: slide 9Design of T-Beam: slide 12
DESIGN OF RECTANGULAR Beam
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.
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
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
Strength Factors
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.
Important DefinitionsBalanced 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.
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 BeamSteel 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.
Flexural Design EquationsSingly Reinforced Beam
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/8If Beam size consider by Architect &Compression zone not perfectTo carry compression load you should be Design doubly Reinforced Beam,
DESIGN OF T- Beam
05/03/2023 13
T BEAM DESIGN : SINGLY & DOUBLY : USD
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.
Fig:T-Beam
Effective flange width of T-Beam:
Strength Analysis:
For case I:Area of concrete section, Area of steel are known a Calculation
Are of concrete section, Area of steel are known
05/03/2023 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
fn2 sf y
2
2
M M M
aM A A f d
hM A f d
For : fha
b
bw
And Nominal moment capacity will be Mn = Mn1+ Mn2
T- Beam Moment calculation
Design of T-Beam:
Moment or
loading is given
Area of steel in flange
Nominal moment
Moment For Web
Area of steel (Web)
Total area of steel
conclusion