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 05/23/2022 1
T Beam USD
Jun 20, 2015
As-salamu alaykum
Welcome to the presentation on “T Beam Design: Singly & Doubly by USD method” Presented By -
S. M. Rahat Rahman
ID: 10.01.03.104
1.Contents :
USD (Ultimate Strength Design Method)
T-beam
T - Beam acts Like Singly Reinforced Beam
T – Action vs rectangular Action
Effective Flange width of t-beam
Strength analysis
Nominal moment for t section
2. USD : Based on the ultimate strength of the structure member assuming a failure condition , due to concrete crushing or yielding of steel. Although there is additional strength of steel after yielding (strain hardening zone) which will not be considered in the design.
Actual loads are multiplied by load factor to obtain the ultimate design loads. ACI code emphasizes this method.
3. T Beam : For monolithically casted slabs, a part of a slab act as a part of beam to resist longitudinal compressive force in the moment zone and form a T-Section. This section form the shape of a "T“ . It can resist the longitudinal compression
4. Occurrence 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.
5. Singly Reinforced Reinforcement is provided in tension zone only
6. Doubly Reinforced > Concrete can not develop the required compressive force to resist the maximum bending moment
> Reinforcement is provided in both compression and tension zone.
7. T-Beam Act As a Singly Reinforced Beam
8. Continuous T Beam :
When T-shaped sections are subjected to negative bending moments, the flange is located in the tension zone. Since concrete strength in tension is usually neglected in strength design, the sections are treated as rectangular sections.
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.
9. Effective Flange Width
10. Strength analysis of T beam
11. Analysis of T beam
12. T Beam moment calculation
Welcome to the presentation on “T Beam Design: Singly & Doubly by USD method” Presented By -
S. M. Rahat Rahman
ID: 10.01.03.104
1.Contents :
USD (Ultimate Strength Design Method)
T-beam
T - Beam acts Like Singly Reinforced Beam
T – Action vs rectangular Action
Effective Flange width of t-beam
Strength analysis
Nominal moment for t section
2. USD : Based on the ultimate strength of the structure member assuming a failure condition , due to concrete crushing or yielding of steel. Although there is additional strength of steel after yielding (strain hardening zone) which will not be considered in the design.
Actual loads are multiplied by load factor to obtain the ultimate design loads. ACI code emphasizes this method.
3. T Beam : For monolithically casted slabs, a part of a slab act as a part of beam to resist longitudinal compressive force in the moment zone and form a T-Section. This section form the shape of a "T“ . It can resist the longitudinal compression
4. Occurrence 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.
5. Singly Reinforced Reinforcement is provided in tension zone only
6. Doubly Reinforced > Concrete can not develop the required compressive force to resist the maximum bending moment
> Reinforcement is provided in both compression and tension zone.
7. T-Beam Act As a Singly Reinforced Beam
8. Continuous T Beam :
When T-shaped sections are subjected to negative bending moments, the flange is located in the tension zone. Since concrete strength in tension is usually neglected in strength design, the sections are treated as rectangular sections.
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.
9. Effective Flange Width
10. Strength analysis of T beam
11. Analysis of T beam
12. T Beam moment calculation
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Transcript
AHSANULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY
DEPARTMENT OF CIVIL ENGINEERING
CE-416PRE-STRESSED CONCRETE LAB
SESSIONAL
PRESENTED BY:S. M. RAHAT RAHMAN
ID NO:10.01.03.044
COURSE TEACHERS:MUNSHI GALIB MUKTADIR
SABREENA NASRIN
T BEAM DESIGN : SINGLY & DOUBLY : USD
USD (ULTIMATE STRENGTH DESIGN METHOD)
T-BEAM
T - BEAM ACTS LIKE SINGLY REINFORCED BEAM
T – ACTION VS RECTANGULAR ACTION
EFFECTIVE FLANGE WIDTH OF T-BEAM
STRENGTH ANALYSIS
NOMINAL MOMENT FOR T SECTION
CONTENTS
ULTIMATE STRENGTH DESIGN(USD)
Assuming tensile failure condition
Additional strength of steel after yielding
ACI code emphasizes this method.
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 .
T-BEAM
Occurrence 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.
SINGLY REINFORCED BEAM
Tension Zone
Compression Zone
Figure : Singly Reinforced Beam for positive moment condition
DOUBLY REINFORCED BEAM
Figure : Doubly Reinforced Beam for positive moment condition
Compression Zone
Tension Zone
T BEAM BEHAVES AS SINGLY REINFORCED BEAM
CONTINUOUS T-BEAM
T-Action
Rectangular
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. Since concrete strength in tension is usually neglected in strength design, the sections are treated as rectangular sections.
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.
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
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
EFFECTIVE FLANGE WIDTHFrom ACI 318, Section 8.10.2
Effective Flange Width :Condition 3
Isolated T Beam
a) beff ≤ 4 bw
b) hf ≥ bw/2
T - SECTION (STRENGTH ANALYSIS)
Strength Analysis :
1st case : (N.A. is with in the flange)
Analyseas a rectangular beam of width
=
T-SECTION (STRENGTH ANALYSIS)
Case 1 : (N. A. is with in Flange)
hf
Strain Diagram Stress Diagram
T-SECTION (STRENGTH ANALYSIS)
Case 2 : (N. A. is with in Web)
ANALYSIS OF T-BEAM
18
Analysis of T-Beams - ( a > hf)
Consider the total section in two parts:
1) Flange overhangs and corresponding steel;2) Stem and corresponding steel;
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
T BEAM MOMENT CALCULATION
For : fha
T BEAM MOMENT CALCULATION
Part-1
0.85 fc’ bw a = As1 fy
Part-2
0.85 fc’ (b-bw) hf = As2 fy
0.85 fc’ bw a + 0.85 fc’ (b-bw) hf = As fy
Where,
As1 = As – Asf
As2 = Asf
Thank you
ANY QUESTION ?
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