T - Beam (USD-Ultimate Strength Design)
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OF SCIENCE & TECHNOLOGY DEPARTMENT OF CIVIL ENGINEERING CE-416 PRE-STRESSED CONCRETE LAB SESSIONAL PRESENTED BY: S. M. RAHAT RAHMAN ID NO:10.01.03.044 COURSE TEACHERS: MUNSHI GALIB MUKTADIR SABREENA NASRIN 10/17/2022 1
Transcript of T - Beam (USD-Ultimate Strength Design)
AHSANULLAH UNIVERSITY OF
SCIENCE & TECHNOLOGY
DEPARTMENT OF CIVIL ENGINEERING
CE-416PRE-STRESSED CONCRETE LAB
SESSIONALPRESENTED BY:
S. M. RAHAT RAHMANID NO:10.01.03.044
COURSE TEACHERS:MUNSHI GALIB MUKTADIR
SABREENA NASRIN10/17/2022 1
T BEAM DESIGN : SINGLY & DOUBLY : USD
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USD (ULTIMATE STRENGTH DESIGN METHOD) T-BEAM T - BEAM ACTS LIKE SINGLY REINFORCED BEAM CONTINUOUS T – BEAM EFFECTIVE FLANGE WIDTH OF T-BEAM STRENGTH ANALYSIS ANALYSIS OF T - BEAM T BEAM MOMENT CALCULATION
CONTENTS
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ULTIMATE STRENGTH DESIGN(USD)
Assuming tensile failure condition
Additional strength of steel after yielding
ACI code emphasizes this method.
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T-BEAM
Concrete beams are often casted integrally with the slab and formed a “T” – shaped beam.
These beams are very efficient .
Here slab portion carries the compressive load and web portion carries the tension .
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T-BEAMOccurrence and Configuration of T-Beams
• Common construction type• The slab forms the beam flange, while the part of the beam projecting below the slab forms is what is called web or stem.
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SINGLY REINFORCED BEAM
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Tension Zone
Compression Zone
Figure : Singly Reinforced Beam for positive moment condition
DOUBLY REINFORCED BEAM10/17/2022 8
Figure : Doubly Reinforced Beam for positive moment condition
Compression Zone
Tension Zone
T BEAM BEHAVES AS SINGLY REINFORCED BEAM
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CONTINUOUS T-BEAM
T-Action
Rectangular
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CONTINUOUS T-BEAM T Versus Rectangular Sections
When T-shaped sections are subjected to negative bending moments, the flange is located in the tension zone.
On the other hand, when sections are subjected to positive bending moments, the flange is located in the compression zone and the section is treated as a T-section.
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EFFECTIVE FLANGE WIDTHFrom ACI 318, Section 8.10.2
Effective Flange Width : Condition 1
For symmetrical T-Beam or having slab on both sides a) 16 hf + bw
b) Span/4 c) c/c distance
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EFFECTIVE FLANGE WIDTHFrom ACI 318, Section 8.10.2
Effective Flange Width : Condition 2 Beams having slabs on one side only a) bw + span/12 b) bw + 6hf
c) bw + 1/2 * beam clear distance
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EFFECTIVE FLANGE WIDTH
From ACI 318, Section 8.10.2
Effective Flange Width :Condition 3
Isolated T Beam
a) beff 4 b≤ w
b) hf b≥ w/2
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T - SECTION (STRENGTH ANALYSIS)
Strength Analysis :
1st case : (N.A. is with in the flange)
Analysis as a rectangular beam of width
=
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T-SECTION (STRENGTH ANALYSIS)
Case 1 : (N. A. is with in Flange)
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hf
Strain Diagram
Stress Diagram
T-SECTION (STRENGTH ANALYSIS)
Case 2 : (N. A. is with in Web)
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ANALYSIS OF T-BEAM
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Analysis of T-Beams - ( a > hf)
Consider the total section in two parts:
1) Flange overhangs and corresponding steel;2) Stem and corresponding steel;
N.A. N.A.
b - bw
bw
ANALYSIS OF T BEAM
Case-1
0.85 fc’ (b-bw) hf = As2 fy
Case-2 0.85 fc’ bw a = As1 fy
0.85 fc’ bw a + 0.85 fc’ (b-bw) hf = As fy
Where,
As1 = As – Asf As2 = Asf
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εc=0.003
d
c
0.85fc’ a/
2
d-a/2
C
T
Strain Diagram
Stress Diagram
As
hf
T BEAM MOMENT CALCULATION
For :
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b
bw
n n1 n2
n1 s sf y
fn2 sf y
2
2
M M MaM A A f d
hM A f d
fha
THANK YOU
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10/17/2022 22ANY QUESTION ?
