This document appears to be a presentation on beams given by a group of civil engineering students at Dhaka University of Engineering & Technology. The presentation covers the definition of a beam, different types of beams classified by shape, design, equilibrium, and support conditions. It also discusses the size, reinforcement, and covering of beams. Key points covered include the types and spacing of longitudinal and transverse reinforcement, as well as the minimum cover requirements. The presentation concludes with descriptions of different failure modes in beams, such as flexural, shear, and diagonal failures.

1. TO THE
PRESENT
WELCOME
TO THE
PRESENTATION
ATION
WELCOME
TO OUR
PRESENTATION

2. Presented by :
Group : B1-2
Name: Student ID
Md. Ekramul Hasan 161075
S. M. Shahedur Rahman 161076
Goutam Kumer 161077
Md. Sabbir Hossain 161078
Md. Azim Uddin 161079
Md. Anwar Hossain 161080
Md. Bappy Alahi 161082
Md. Al-Mamun 161083
Sudip Paul 161084
Md. Sadiqul Islam 161085
Department of Civil Engineering
Dhaka University of Engineering & Technology, Gazipur
Gazipur-1707

3. Presented to :
Md. Suman Mia
Assistant Professor
Department of Civil Engineering
Dr. Md. Khasro Miah
Professor
Department of Civil Engineering
Md. Tarek Hasan
Lecturer
Department of Civil Engineering
Dhaka University of Engineering & Technology, Gazipur
Gazipur-1707

4. DHAKA UNIVERSITY OF ENGINEERING & TECHNOLOGY, GAZIPUR
GAZIPUR - 1707
PRESENTATION ON
BEAM

5. Contents to be discribed:
• Definition
• Types of beam
• Size of beam
• Reinforcement in beam
• Covering
• Failure of beam

6. What is beam?
• A beam is a structural element that
primarily resists loads applied laterally
to its axis.
The governing forces of a beam are:
1. shear force
2. bending moment
3. Torsion
( Axial force is negligible )

7. Beam can be classified according to the :
•Shape
•Placement of reinforcement
•Design
•Equilibrium
•Support condition

8. Types of beam according to shape:
• Rectangular section
• T – section
• I – section
• L - section
• Triangle section
• Circular section

9. Types of beam according to design:
• Balance reinforcement:
Concrete & reinforcement reach to yield strain simultaneously.
• Under reinforcement:
Reinforcement reach to yield strain before concrete & give signal
before fail.
• Over reinforcement:
Concrete reach to yield strain before reinforcement & there is no
warning sign & cause sudden collapse.

10. Types of beam according to equilibrium:
• Statically determinate
Number of equation ≥number of unknown.
• Statically indeterminate
Number of equation < number of unknown.

11. Types of beam according to support condition:

12. Types of beam according to Placement of reinforcement
• Singly reinforced:
1. Reinforcement are used to resist tensile stress. .
• Doubly reinforced:
Reinforcement are used to resist both
1. compression and tensile stress.
2. When section is fixed and need
more strength of beam.

13. Size of beam:

14. Different types of reinforcement:
1. Longitudinal reinforcement are used:
To resist flexural stress
To resist shear stress
To resist torsional stress
2. Transverse reinforcement are used:
To resist shear & diagonal tension
To hold longitudinal reinforcement
 To reduce shear crack propagation

15. Reinforcement in beam:
Minimum reinforcement
Maximum reinforcement
but not more than .025 (BNBC: 8.3.4.2)
where,
At least two bar will be provided continuously at top and bottom
N.B. For brick aggregate concrete will be increased 50%

16. Reinforcement in beam:
Size of stirrups:
According to ACI:
• #3 (10mm) bar if longitudinal bar ≤ # 10 (32mm )
• #4 (12mm) if longitudinal bar ≥ #11 (36 mm)
According to BNBC:
#3 (10mm) if main bar < 30mm
#4 (12mm) if main bar ≥ 32mm
 The stirrups hook should be bend to 135 degree.
 Hook extension is 6db or 75mm

17. Reinforcement in beam:
 The minimum clear spacing between parallel
bars in a layer shall be db, but not less than 1”
Where parallel reinforcement is placed in two
or more layers, bars in the upper layers shall be placed
directly above bars in the bottom layer with clear
distance between layers not less than 1”
( According to ACI-3.3.2.)

18. Reinforcement in beam: ( Stirrups )
Spacing according to BNBC-8.3.10.4:
Maximum spacing ( Mid span )
• d/2
• 16x maximum dia of main bar
• 48x dia of stirrup
N.B. The first stirrup shall be located not more than 50mm from the support face
Maximum spacing (hoops)
• d/4
• 8x minimum dia of main bar
• 300mm
N.B. Stirrups should not be placed more than d/2 distance throughout the length
of the beam

19. Covering :
According to ACI-7.7.6 code: Minimum covering ( in )
Concrete cast in contact of earth ……………………..……… 3”
Concrete expose to earth or weather
#6 to #18 longitudinal bar ………….…….……….……….. 2”
Longitudinal bar ≤ #5 ………….……. .…………… 0.5” to 1”.
Concrete not exposed to weather or in contact with ground… ¾”

20. Failure of beam
Mainly two types of failure occurs in beam:
Flexural failure
Occur at mid span of beam.
Shear failure:
Occur at support face.
Also a failure mode is diagonal failure:
Combination of shear & flexural
failure

21. Example failure of beam:

22. Have you any question?

23. THANK YOU EVERY ONE