Staircases gnk(1)

STAIRCASES G.NAGESH KUMAR Sr. Asst. Prof.

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

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.

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.

STAIRS AND ITS TYPES ,[object Object]

Geometrical stairs,[object Object]

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. .

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.

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

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

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.

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

Half Space Landing ,[object Object]

Landing width = width of stair (min 750mm)

Used in Dogleg Stairs,[object Object]

Landing Width & Length = Stair Width

Forms Quarter Turn Stair (min 750mm),[object Object]

Required where more than 18 Risers

Length = Stair Width or greater,[object Object]

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.

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.

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.

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.

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

Stair Types Double Closed Stair

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

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

Quarter Turn StairOpen Newel Stair

Rise & Going must stay the same within flight

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Determine Steel Square Mathematically 40mm Margin

Determine Steel Square Mathematically

Staircases gnk(1)

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Destaque

Destaque (20)

Semelhante a Staircases gnk(1)

Semelhante a Staircases gnk(1) (20)

Último

Último (20)

Staircases gnk(1)