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![Guide lines for fixing the dimensionsGuide lines for fixing the dimensions
Rise (R) : 150mm to 180mm
Tread (T) : 220 mm to 250 mm- for residential buildings.
Rise (R) : 120 to 150 mm
Tread (T) : 250 mm to 300 mm – for public buildings
[T + 2R] : Between 500 mm to 650 mm
The width of the stair
• 0.8 m to 1 m for residential building and
• 1.8 m to 2 m for public building.](https://image.slidesharecdn.com/staircases-130520232545-phpapp01/85/How-do-you-takeoff-a-staircase-12-320.jpg)
![EFFECTIVE SPAN FOR
LONGITUDINALLY
SPANNING STAIRCASES
X X Y Y
Le
Case (c)
Case (b)
Le
Le=G +[ X +Y], X ≤1m AND Y ≤1m
Le=c/c of beams
GOING=G](https://image.slidesharecdn.com/staircases-130520232545-phpapp01/85/How-do-you-takeoff-a-staircase-18-320.jpg)
![ROW OF CHAIRS
500 mm
500 mm
GL
Wall
FOUNDATION
GROUND FLIGHT
MAIN STEEL
# 12 @ 120
DIST. STEEL
# 8 @ 200
150
Ld =564
REINFORCEMENT
FROM BM
Ld =564
FLOOR LEVEL
LANDING FIRST FLIGHT
R=160
T= 250
LAP L
DETAILING
Landing and flight spans longitudinally
[A]
[C]
[D,E]-
Anchorage
steel
Main steel [B]](https://image.slidesharecdn.com/staircases-130520232545-phpapp01/85/How-do-you-takeoff-a-staircase-24-320.jpg)
How do you takeoff a staircase?
- 1. Summary Sheet Session Number: Date : Subject Expert : 1 12.03.2007 Dr. M.C. NatarajaDr. M.C. Nataraja Professor Department of Civil Engineering, Sri Jayachamarajendra College of Engineering, Mysore – 570 006. Phone:0821-2343521, 9880447742 E-mail: nataraja96@yahoo.com
- 2. Learning Outcomes: • Afterthis students will be able to do the detailing ofAfter this students will be able to do the detailing of staircases through drawing and bar bendingstaircases through drawing and bar bending schedule.schedule. DETAILING OF STEEL IN STAIR CASES
- 3. Contents • Definition andparts of Stair cases • Types of stair cases • Requirements • Detailing principles • Problems • Art of Drawing • Bar bending schedule Detailing of steel in Stair cases
- 4. STAIR CASE Definition Stair casesare used for the purpose of giving access to different floors of a structure.
- 5. Parts of staira caseParts of stair a case G T N R W θ Le L1 L2 FLIGHT FIG.1 PARTS OF STAIR CASE Fig. 2 DOG LEGGED STAIR CASE
- 6. Parts of stairsPartsof stairs Flight and landing. Steps Rise-R Going-G=T-N Tread-T Nosing -N G T N R W θ
- 7. Types of staircasesTypes of stair cases Based on shape • Straight stairs • Dog legged stairs • Open well or open newel stairs • Geometrical stairs such as spiral, circular, etc. • Free standing stair cases
- 8. Straight SC Geometric SC Doglegged SC Transversely spanning SC Some photos
- 9. Open Well orNewel stair casesOpen Well or Newel stair cases I- FLIGHT II- FLIGHT III- FLIGHT LANDING WITH INTERMEDIATE FLIGHT WITHOUT INTERMEDIATE FLIGHT OPEN WELL OPEN WELL
- 10. OTHER STAIRCASESOTHER STAIRCASES SPIRALAND GEOMETRIC STAIRCASES RISER AND TREAD STAIRCASE
- 11. Based on typeof spanBased on type of span • Horizontally spanning or transversely spanning SC • Longitudinally spanning SC. For details refer IS:456-2000 and SP-34. CLASSIFICATION
- 12. Guide lines forfixing the dimensionsGuide lines for fixing the dimensions Rise (R) : 150mm to 180mm Tread (T) : 220 mm to 250 mm- for residential buildings. Rise (R) : 120 to 150 mm Tread (T) : 250 mm to 300 mm – for public buildings [T + 2R] : Between 500 mm to 650 mm The width of the stair • 0.8 m to 1 m for residential building and • 1.8 m to 2 m for public building.
- 13. Guide lines forfixing the dimensionsGuide lines for fixing the dimensions Contd…Contd… • The width of the landing is equal to the width of stairs. • The number of steps in each flight should not be greater than 12 • The pitch of the stair should not be more than 38 degrees. • The head room measured vertically above any step or below the mid landing shall not be less than 2.1 m.
- 14. Design of stairsDesignof stairs Design for maximum bending moment and check for maximum shear force. The depth is to be fixed from deflection criteria. Stair case slab is designed as a conventional slab. All rules regarding the detailing are similar to that of slab. Enough development and anchorage lengths for steel should be provided.
- 15. Transversally spanning staircaseTransversally spanning stair case STEPS STRINGER BEAMS STRINGER BEAM 0.5 Ast 0.1Le-0.15Le Le Ast D1 D2 STIRRUP MAIN STEEL DIST. STEEL Refer SP-34 for more details
- 16. MAIN Ast 0.5Ast DS DB bW L 6φm Le 0.1-0.15Le φm DS STAIR CASESUPPORTED ON SIDE BEAMS-DETAILS STIRRUP DETAILS AND HOOK TRANSVERSLY SPANNING
- 17. Le LANDING WAIST SLAB Case (a) EFFECTIVESPAN FOR LONGITUDINALLY SPANNING STAIRCASES WALL WAIST SLAB SUPPORTED AT THE ENDS OF LANDINGS
- 18. EFFECTIVE SPAN FOR LONGITUDINALLY SPANNINGSTAIRCASES X X Y Y Le Case (c) Case (b) Le Le=G +[ X +Y], X ≤1m AND Y ≤1m Le=c/c of beams GOING=G
- 19. Longitudinally spanning SCLongitudinallyspanning SC DetailingDetailing • Steel at bottom longitudinally-tension • Anchorage and development steel • Distribution steel • Row of chairs • Nominal foundation for ground flight
- 20. ExerciseExercise A dog leggedstair case is to be detailed with the following particulars: Clear dimension of stair case room=4.48 m x 2.1 m The floor to floor height is 3.2 m Width of each tread =250 mm Width of each rise = 160 mm Thickness of waist slab = 150 mm Width of flight =1m All round wall = 230 mm
- 21. ExerciseExercise contd.,contd., Both flightsare supported at the ends of landing on 230 mm wall. (Landing and flight spans in the same direction) The first flight starts from the plinth level Main steel for each flight = #12@120 Distribution steel for each flight = #8@ 200 Use M20 concrete and Fe 415 steel. Draw to a suitable scale The plan of stair case Sectional elevation of the Ground flight Sectional elevation of the First flight Bar bending schedule
- 22. SolutionSolution Dimensioning: R=160 mm, T=250 mm Floor to floor height = 3200mm No of rises = 3200/R = 20. Each flight has 10 rises. No of treads per flight=10-1 =9 Width of landing along flight = (4480-9x250)/2 = 1115mm. Going of flight=9x250 =2250mm Development length = 47φ= 47 x 12 = 564 mm
- 23. ExerciseExercise Plan of staircase PLAN 1115 mm 1115 mm2250 mm Le = 4710 mm Gap=0.1m 2100 Clear dimension of stair case room=4.48 m x 2.1 m
- 24. ROW OF CHAIRS 500mm 500 mm GL Wall FOUNDATION GROUND FLIGHT MAIN STEEL # 12 @ 120 DIST. STEEL # 8 @ 200 150 Ld =564 REINFORCEMENT FROM BM Ld =564 FLOOR LEVEL LANDING FIRST FLIGHT R=160 T= 250 LAP L DETAILING Landing and flight spans longitudinally [A] [C] [D,E]- Anchorage steel Main steel [B]
- 25. Y=0.3 l orLd LANDING BEAM 500 500 GL FOOTING GROUND FLIGHT FIRST FLIGHT MAIN STEEL # 12 @ 120 DIST. STEEL # 8 @ 150 LANDING BEAM 150 X l Y Y 150 INTERMEDIATE LANDING ROW OF CHAIRS X = 0.15 l or Ld MAIN STEEL DS 150 PLANLe DETAILING Flight spans longitudinally on landing beams
- 26. Ld Ld T Extra steel if needed Concretespalling due to tension in steel Wrong ok Details at the junction of flight and landingDetails at the junction of flight and landing
- 27. STRAIGHT STAIR CASESTRAIGHTSTAIR CASE Refer SP-34 and learn the details
- 28. Member Mark No. of bars Dia. in mm Length in m/piece Total length inm Bar details Remarks #12 #8 SC GFl A 9 12 measure X1 8 spacings, main bar B 9 12 measure X2 Main bar C Count 8 960 Y1 Dist. Bar L=1000- 2EC Bar bending schedule For exercise problem
- 29. Stair- Ground Floor D 9 12measure X3 Anchorage bars E 9 12 measure X4 Anchorage bars Total length in m/diameter - - Calculations are based on actual measurement on drawing sheet. Weight in kg/m -- -- Total weight in kg/diameter --- --- Bar bending schedule- Contd.,
- 30. Estimation of quantityof concrete Volume of concrete = L x B x D L= length along the central line in m-measured B=Breadth in m D=Thickness of slab in m Plus concrete in footing Weight of concrete, kg = Volume x density
- 31. Conclusion Students have learntthe following: • Types of staircases. • Effective span concept. • Requirements of staircase. • Detailing of steel. • Importance of development length and anchorages. • Drawing to scale and bar bending schedule.
- 32. The end Thank youvery much Dr. M. C. Nataraja