Presentation on Detailing of Column by TULIP [Autosaved].pptx

detailing of column

1. TO OUR PRESENTATION DETAILING OF REINFORCED CONCRETE COLUMN PREPARED BY : GROUP 02

2. Presented by :- Team Tulip

3. Prof. Dr. Md. Khasro Miah Civil Engineering Department. Dhaka University of Engineering & Technology, Gazipur . Tasnim Nishat Aishee Lecturer, Civil Engineering Department. Dhaka University of Engineering & Technology, Gazipur . Presented to:-

4. OVERVIEW Theory Code Provisions Design & Calculation Detail- Drawing

5. THEORY Definition:- According to BNBC 2020, a column is a structural member that supports axial load primarily by inducing compressive stress along the fibers. Governing Forces :- • Axial force is the governing force but shear force and bending moment may exist.

6. THEORY TYPES OF COLUMNS :- Columns are classified based on several conditions, which include: Based on the Slenderness Ratio Based on Types of Reinforcement Based on Types of Loading Based on Shape

7. THEORY Based on the Slenderness Ratio :- Short Column: L/r ≤ 80 Long Column: L/r > 120 Intermediate Column : L/r ≥(80 ~ 120)

8. THEORY Based on Reinforcement Pattern:- Tied Column Spiral Column Composite Column Spiral Spiral

9. THEORY Based on Types of Loading:- Axially Loaded Column Eccentrically Loaded Column Uniaxially Eccentric Load Biaxial Eccentric Load

10. THEORY Based on Shape :- Square section Rectangular section Circular section L-section T-section

11. Code Provisions TYPES OF REINFORCEMENT IN COLUMNS Lateral ties Longitudinal bar ement Spiral Longitudinal bar ement

12. Code Provision 1. Rectangular Column: (BNBC 8.3.5.1) Slenderness condition h ≤2.5𝑏 Where, h= longer cross-sectional side, 𝑏 = shorter side The height must be more than 3× the least lateral dimension Least dimension of column d ≥12″ Size of column

13. Code Provisions 2.Circular Column:- Minimum diameter 12″ (300 mm) Minimum 6 longitudinal bars symmetrically arranged Spiral or circular ties for confinement Circular column

14. Code Provision Area of Longitudinal Reinforcement: (BNBC 8.3.5.3) For non-composite compression members, the reinforcement ratio must follow 0.01≤ 𝜌 𝑔 ≤ 0.06 Preferred reinforcement ratio 𝜌 𝑔 ≤ 0.04 , To avoid practical difficulties in placing and compacting of concrete, unless absolutely essential.

15. Code Provision Minimum Number of Longitudinal Bars: (BNBC 6.3.5.4.2) 4 bars in rectangular arrangements enclosed by ties. 6 bars in circular arrangement enclosed by tie or spiral reinforcement. 3 bars in a triangular arrangement enclosed by ties . For tied column, Longitudinal Steel Area , Ast :- 𝜌 g = Here , A g = Gross cross-sectional area A st = Area of steel.  

16. Code Provision The size of lateral ties (BNBC 2020 8.1.9.4) 10mm (#3) dia bar if longitudinal bar ≤ 32mm (#10) dia bar 12mm (#4) dia bar if longitudinal bar ≥ 36mm (#11) dia bar 12mm (#4) dia bar if longitudinal bars are bundled Reinforcement Requirements (Spirals ):- The size of lateral spiral (BNBC 8.1.9.3) not less than 10mm in diameter for cast-in-place constructions.

17. Code Provision SPACING FOR REINFORCEMENT :- Maximum spacing for ties : (BNBC 8.1.9.4) S ≥ 16d b ( d b for longitudinal bars ) S ≥ 48d t ( d t for tie bar ) S ≥ Least lateral dimension of column Maximum spacing for spirals : (BNBC 8.1.9.3) Pitch = 1.0 in. to 3.0 in. (25mm-75mm)

18. Code Provision Minimum Clear Spacing between longitudinal bars in Column:- Larger of 1.5 bar diameter or 1.33 times of coarse aggregate or 1 inch Maximum value from the above.

19. Code Provision STANDARD HOOKS (BNBC 8.1.2.1) For longitudinal bar 180° bend + min. 4d b extension, but ≥ 65 mm 90° bend + min. 12d b extension

20. Code Provision STANDARD HOOKS (BNBC 8.1.2.1) For Stirrups & Ties: If dia of bar ≤16 mm : 90° bend + 6d b extension 19–25 mm dia bar: 90° bend + 12d b extension ≤25 mm dia bar:135° bend + 6db extension Closed / Continuously wound ties:135° bend + 6db, but ≥ 75 mm extension

21. Assigned column (15”    

22. Calculation Column dimension = 15″× 24″ Floor Height = 10′ A st =7.92 inch 2 Beam Depth = 21″ Clear Span of Column = 10  

23. Calculation Check for column size According to BNBC Least dimension of column should be greater than 12″. -Here, Least dimension 15″ >12″ And Other dimension h ≤ 2.5b -So, 24″ ≤37.5″ Ratio of height to least dimension > 3 = = 8 > 3  

24. Design & Calculation Reinforcement Check Steel Ratio: ρ g = = = 0.022 According to BNBC 0.01 ≤ ρ g ≤ 0.06 . Hence , ρ g =0.022 which lies in the range above mentioned. So, (OK).  

25. Calculation Longitudinal bars: Using 18-#6 A st = 18×0.44 = 7.92 inch 2 As per BNBC minimum of 4 bars used as longitudinal bars in rectangular arrangements. We have used 18 bars (even numbers ) So, OK.

26. Calculation Clear Spacing along long dimension, S 1 = = 2.5″ Clear Spacing along short dimension, S 2 = = 2.75″ Spacing criteria for Longitudinal reinforcement: S 1.5 dia. Of main bar; 1.5 6/8 =1.125 ″ S 1.33aggregate size ; 1.33 3/4 =0.9975 ″ Or 1 in. Both S 1 & S 2 are larger than 1.125 ″ So, (OK).  

27. Calculation Tie Bars: #3 (10mm.) bar used as tie; as longitudinal bar dia < 32mm. Clear spacing of tie bar at mid span : 16 × main bar dia. = 16 × 6/8 = 12″ c/c 48 × tie bar dia. = 48 × 0.375 = 18″ c/c least lateral dimension of column = 15″ c/c So, Using #3 bar @ 12″ c/c .

28. Calculation Clear spacing of tie bar at Confinement zone: 8 × main bar dia = 8 × 6/8 = 6″ c/c 24× tie bar dia = 24 × 0.375 = 9″ c/c = = 7.5″ c/c 10″ c/c ؞ Using #3 bar @ 6″ c/c.  

29. Calculation Confinement zone Calculation : B max = 24 inch 18 So , the Confinement zone length, L is .  

30. Calculation Spacing for Lapping ( if provided): In lap region tie should be provided closely as same as end region of confined zone spacing. So, it is 6 in. c/c. Lapping Length: 48 Dia. Of main bar, i.e ; 48  

31. Calculation Bend & Hooks: Tie should be bent at 135 Hooks extension = 6d b ≥ 3″ = 2.25″ > 3″ So, Hook Extension 3 ″  

32. Detail Drawing

33. Detail Drawing

34. THANK YOU FOR YOUR PAITENCE