Types of Staircases

1. STAIRCASES G.NAGESH KUMAR Sr. Asst. Prof.

2. Stairs are the medium through which a person can travel from one horizontal level to another horizontal level although it connects two different horizontal levels. STAIRS

3. STAIRCASE: A stair is a set of steps leading from one floor to the other. It is provided to afford the means of ascent and descent between various floors of the building. The room or enclosure of the building, in which the stair is located, is known as staircase.The opening or space occupied by the stair is known as a stairway. In a domestic building the stairs should be centrally located to provide easy access to all rooms. In public buildings, stairs should be located near the entrance. Stairs may be constructed by timber, bricks, stone, steel or reinforced cement concrete.

4. Staircases provide access and communication between floors in multi-storey buildings, and are a path by which fire can spread from one floor to another. Staircase, therefore, must be enclosed by fire resisting walls, floors, ceiling and doors. It is desirable that the linings to the walls and the ceilings are non- combustible and of low flame spread. Another important aspect in the design of stairs is the strength aspect. It must be designed to carry certain loads, which are similar to those used for the design of floor.

6. Double flight straight stairs

7. Quarter turn newel

8. Half turn newel

9. Open well stairs

10. Dog legged stairs

11. Bifurcated stairs

12. Circular stairs

13. Spiral stairs

15. Types of Stairs Quarter Turn

16. HALF TURN NEWEL In half turn newel stairs the stairs runs straight and after reaching the landing it turns to left or right and then climbs up to next two to three steps and reaches a landing and these steps again turns in the direction from where the user was approaching reaching finally to the consecutive horizontal level. OPEN WELL STAIRS These are like normal doglegged stairs but the only difference is that after reaching the landing the stairs ends up with a railing instead of the wall. .

17. Stair Types

18. DOG LEGGED STAIRS Dog legged stairs are the stairs in which the user climbs up to a flight turns at one eighty degree and then climb stairs in opposite direction BIFURCATED STAIRS In bifurcated stairs the stairs runs at a flight an as it reaches the landing the stairs runs from left and right side reaching the same horizontal level these stairs are provided generally in atrium of a building.

21. CIRCULAR STAIRS The stairs made in in a circular form are known as the circular staircase.

22. SPIRAL STAIRSThose stairs which are in spiral form is known as spiral staircase. Spiral

23. GEOMETRIC STAIRS Geometric

25. The technical terms associated with the design and constructions of stairs are:TREAD: it is the upper horizontal portion of a step upon which the foot is placed while ascending or descending.RISER: it is the vertical portion of a step providing a support to the tread. FLIGHT: this is defined as an unbroken series of steps between landings.LANDING: it is the level platform at the top or bottom of a flight between the floors. A landing facilitates change of direction and provides an opportunity for taking rest during the use of the stair.

26. 2 Flights 1 Flight Definition – Flights Between Landings Dogleg Closed Riser Straight Open Riser

28. Landing width = width of stair (min 750mm)

30. Landing Width & Length = Stair Width

32. Required where more than 18 Risers

33. May be used to give a rest

34. Width = Stair Width

36. RISE: it is the vertical distance between two successive tread faces.GOING: it is the horizontal distance between two successive riser faces. STRINGS AND STRINGERS: these are the slopping members which support the steps in a stair. They run along the slope of the stair.NEWEL POST: newel post is a vertical member which is placed at the ends of flights to connect the ends of strings and hand rail.

37. BALUSTER: it is vertical member of wood or metal, supporting the hand rail.HAND RAIL: it is the surrounded or moulded member of wood or metal following generally the contour of the nosing line, and fixed on the top of balusters.

38. STAIRS OF DIFFERENT MATERIALS TIMBER STAIRS: these stairs are light in weight and easy to construct, but they have very poor fire resistance. They are used only for small rise residential buildings. Sometimes, fire resisting hard wood of proper thickness may be used. STONE STAIRS: these are widely used at places where ashlar stone is readily available. Stone stairs are quite strong and rigid, though they are very heavy. Stone used for construction of stairs should be hard, strong and resistant to wear. The simplest form of stone stairs is those supported on both the ends, though an open well stair case can also be built. BRICK STAIRS: these are not very common, except at the entrance. However, brick stairs of single straight flight are often made in village houses. The stairs consist of either solid wall, or also, arched openings may be left for obtaining storage space.

39. METAL STAIRS: stairs of mild steel or cast iron are used only as emergency stairs. They are not common in residential and public buildings, though they are strong and fire resistant. These are commonly used in factories, godowns, workshops, etc. R.C.C: these are the stairs widely used for residential, public and industrial buildings. They are strong, hard wearing and fire resisting. These are usually cast- in – situ and a wide variety of finishes can be used on these.

40. Timber Stairs

41. Metal Stairs

42. Concrete Stairs

43. Stone Stairs

44. Glass Stair

45. Combination of Materials

46. Parts of Stairs

47. Parts of Stairs

48. Parts of Stairs

49. Parts of Stairs

50. Parts of Stairs

51. Parts of Stairs

52. Parts of Stairs

53. Parts of Stairs

54. Parts of Stairs

55. Parts of Stairs

56. Parts of Stairs

57. Winders Treads that are tapered Must have same rise as the flights Maximum of 3 treads per quarter turn Must be same width at centre on widths < 1m If stair > 1m same width 400mm from inside handrail

58. Winders

59. MODELS OF STAIRS

61. Stair Types

62. Stair Types Double Closed Stair

63. Stair Types

64. Stair Types

65. Double Open Sided Stairs

66. In this case one side is closed while the other is open

67. The Bracketed Stairs refers to decoration & Cut String Also Known as Cut String

68. Quarter Turn StairOpen Newel Stair

69. Spine String Stair

72. GEOMETRICAL STAIRS

77. Definitions

78. Rise & Going must stay the same within flight

80. THANK YOU

81. Quarter Turn Stair

83. BCA Requirements

84. Stair Requirements

85. Calculate StairNo Restriction on Going Best Going 2R + G Between 550 to 700 Midpoint = 625 Determine Total Rise = 2700 Say 175mm Select suitable Rise = 2700/175 = 15.429 Divide Total Rise by Rise Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75mm Use 180mm is closer to 175mm

86. Determine Best Going BCA states that going must be within the range 2 x Rise (R) + Going(G) = 550 to 700 We can assume that the best answer is the Midpoint (550 + 700)/2 = 625 Best Going 2R + G = 625 Best Going G = 625 – 2R

87. Calculate StairNo Restriction on Going Best Going 2R + G Between 550 to 700 Midpoint = 625 Determine Total Rise = 2700 Say 175mm Select suitable Rise = 2700/175 = 15.429 Divide Total Rise by Rise Either 15 or 16 Risers = 2700/15 = 180mm (Use) 2700/16 = 168.75mm Determine Best Going 2R + G = 625 G = 625 – 2R Best Going for180 Riser 265 = 625 – 2 x 180 Either Rise 180 Going 265

88. Calculate StairNo Restriction on Going Use Rise 180 Going 265 15 Risers 14 Goings

89. Calculate StairRestriction on Going Best Going 2R + G Between 550 to 700 Midpoint = 625 Preferred Rise 175mm Divide Total Rise by Rise = 2700/175 = 15.429 Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75 Use 180mm Determine Best Going 3800/14 = 271.43 + 2 x 180 = 631. 43 (Closest) 3800/15 = 253.33 + 2 x 168.75 = 591 15 Risers 14 Goings Use Rise 180 Going 271.43

90. Calculate Stair Flight with Quarter Turn Stair width 900mm Once an Intermediate Landing is introduced the top flight becomes constrained

91. Calculate Stair Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 G = 625 – 2R Stair width 900mm Preferred Rise = 165mm 2700/165 = 16 .364 16 2700/16= 168.75 (3.75 Diff) 2700/17= 158.824 (6.176 Diff) Use Rise = 168.75 Best Going = 625 – 2R = 625 – 2 x 168.75 = 287.5 1800/287.5 = 6.261 6 1800/6 = 300 (12.5 Diff) 1800/7 = 257.143 (30.357 Diff) Rise = 168.364 Going = 300

92. Calculate Stair Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 G = 625 – 2R Stair width 900mm Preferred Rise = 165mm 2700/165 = 16 .364 16 2700/16= 168.75 (3.75 Diff) 2700/17= 158.824 (6.176 Diff) Use Rise = 168.75 Best Going = 625 – 2R = 625 – 2 x 168.75 = 287.5 1800/287.5 = 6.261 6 1800/6 = 300 (12.5 Diff) 1800/7 = 257.143 (30.357 Diff) Rise = 168.364 Going = 300

93. Calculate StairConstrained Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 625- 2 x 180 = 265 Stair width 900mm From Previous we know 15 Risers at 180 Length of 1st Flight = 2700 - 900 Divide by Best Going = 1800/265 = 6.79 Going Either 1800 /6 = 300mm 1800/7 = 257mm 257.14 is Closest to 265

94. Calculate StairConstrained Flight with Half Space Landing Preferred Riser 170mm 3600/170 = 21.176 21 3600/21 = 171.429 3600/22 = 163.636 Use 171.429mm Best Going = 625 – 2R = 625 – 2 x 171.429 = 282.142 Length of 1st Flight = 4050 – 900 = 3150 Divide by Best Going = 3150/282.142 = 11.16 11 3150/11 = 286.364 - 3150/12 = 262.500 Use 286.364 Stair width 900mm

95. Calculate StairConstrained Flight with Half Space Landing Preferred Riser 170mm Rise 171.429mm Going 286.364 Stair width 900mm

96. Calculate StairConstrained Flight with Quarter Turn Winders Preferred Riser 170mm 4100/170 = 24.118 24 4100/24 = 170.833 25 4100/24 = 164 Use Rise 170.833 Best Going 625 – 2R = BG 625 – 2 x 170.833 = 283.334 2650/ 283.334 = 9.353 2650/9 = 294.444 (USE) 2650/10 = 265 Rise 170.833 Going 268.75 Stair width 900mm

97. Calculate StairConstrained Flight with Quarter Turn Winders Preferred Riser 170mm 4100/170 = 24.118 24 4100/24 = 170.833 25 4100/24 = 164 Use Rise 170.833 Best Going 625 – 2R = BG 625 – 2 x 170.833 = 283.334 2650/ 283.334 = 9.353 2650/9 = 294.444 (USE) 2650/10 = 265 Rise 170.833 Going 294.444 Stair width 900mm

98. Calculate StairConstrained Flight with Half Space Landing Stair width 950mm Preferred Riser 170mm 3400/170 = 20 3400/20 = 170 Rise Best Going = 625 – 2R = 625 – 2 x 170 = 285 2400/285 = 8.421 8 2400/8 = 300 (15 Diff) 2400/9 = 266.667 (18.3 Diff) Rise 170 Going 300

99. Calculate StairConstrained Flight with Half Space Landing Stair width 950mm Preferred Riser 170mm 3400/170 = 20 3400/20 = 170 Rise Best Going = 625 – 2R = 625 – 2 x 170 = 285 2400/285 = 8.421 8 2400/8 = 300 (15 Diff) 2400/9 = 266.667 (18.3 Diff) Rise 170 Going 300 With all examples either answer will comply and you should consult with your client and/or Architect

100. Determine Steel Square Mathematically 40mm Margin

101. Determine Steel Square Mathematically

102. Determine Steel Square Mathematically Stair Pitch = 29.54⁰ Zoom In

103. Determine Steel Square Mathematically Stair Pitch = 29.54⁰ Margin Line

104. Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰

105. Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰ Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ X X = 40 ÷ Sin 29.54 X = 81.131

106. Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰ Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ X X = 40 ÷ Sin 29.54 X = 81.13

107. Determine Steel Square Mathematically Set Out For Steel Square Going Going + Margin ÷ Sin Ѳ = 300 + 40 ÷ Sin 29.54⁰ = 381.13mm Ѳ

108. Determine Steel Square Mathematically Set Out For Steel Square Rise Ѳ

109. Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 Ѳ

110. Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 This Angle must = 29.54⁰ Y = 40 ÷ Cos 29.54⁰ Y = 45.9763 Ѳ

111. Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 This Angle must = 29.54⁰ Y = 40 ÷ Cos 29.54⁰ Y = 45.9763 Ѳ

112. Determine Steel Square Mathematically Set Out For Steel Square Rise Rise + Margin ÷ Sin Ѳ = 170 + 40 ÷ Sin 29.54⁰ = 170 + 45.98 = 215.98 Ѳ