Presentation o beam
Download as PPTX, PDF2 likes2,524 views
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.
Presentation o beam
- 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