staircases bcgca3016b. types of stairs straight open riser dogleg closed riser definition –...

Staircases

BCGCA3016B

Types of Stairs

Straight Open Riser

Dogleg Closed Riser

Definition – Flights Between Landings

1 Flight2 Flights

Straight Open Riser

Stair Types

Double Closed Stair

Stair Types

Stair Types

Double Open Sided Stairs

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

Note The Bracketed Stairs refers to decoration & Cut String

Also Known as Cut String

Quarter Turn StairOpen Newel Stair

Spine String Stair

Types of Stairs

Geometric Spiral

Types of Stairs

Quarter Turn

Parts of Stairs

Half Space Landing

•Change stair direction 180⁰•Landing width = width of stair (min 750mm)•Used in Dogleg Stairs

Quarter Space Landing

•Change Stair Direction 90⁰•Landing Width & Length = Stair Width•Forms Quarter Turn Stair (min 750mm)

Intermediate Landing

•Allows the Stair to continue in same direction•Required where more than 18 Risers•May be used to give a rest•Width = Stair Width•Length = Stair Width or greater

Quarter Space Landing

Quarter Turn Stair

Winders

Materials Used in Stair Construction

• Timber• Metal• Stone• Glass

Timber Stairs

Metal Stairs

Concrete Stairs

Stone Stairs

http://upload.wikimedia.org/wikipedia/commons/8/87/Potemkinstairs.jpg

Glass Stair

Combination of Materials

http://www.todstairs.com.au/Stair%20Parts/Parts%20of%20a%20STAIR%20diagram.pdf

Definitions

Rise & Going must stay the same within flight

BCA Requirements

Stair Requirements

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

Winders

Calculate StairNo Restriction on Going

Determine Total Rise = 2700

Select suitable Rise Say 175mm

Divide Total Rise by Rise = 2700/175 = 15.429

Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75mmUse 180mm is closer to 175mm

Best Going 2R + G Between 550 to 700Midpoint = 625

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


Determine Total Rise = 2700

Select suitable Rise Say 175mm

Divide Total Rise by Rise = 2700/175 = 15.429

Either 15 or 16 Risers = 2700/15 = 180mm (Use) 2700/16 = 168.75mm


Either

Rise 180Going 265

Determine Best Going 2R + G = 625G = 625 – 2R

Best Going for180 Riser 265 = 625 – 2 x 180


UseRise 180Going 265

15 Risers

14 Goings

Calculate StairRestriction on Going

Preferred Rise 175mmDivide Total Rise by Rise = 2700/175 = 15.429

Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75

Use 180mmDetermine Best Going3800/14 = 271.43 + 2 x 180 = 631. 43 (Closest)3800/15 = 253.33 + 2 x 168.75 = 591


UseRise 180Going 271.43

15 Risers

14 Goings

Calculate Stair Flight with Quarter Turn

Stair width 900mmOnce an Intermediate Landing is introduced the top flight becomes constrained

Calculate Stair Flight with Quarter Turn

Stair width 900mm Preferred Rise = 165mm

2700/165 = 16 .364

16 2700/16= 168.75 (3.75 Diff)172700/17= 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)71800/7 = 257.143 (30.357 Diff)

Rise = 168.364Going = 300

Best Going 2R + G Between 550 to 700Midpoint = 625G = 625 – 2R

Calculate StairConstrained Flight with Quarter Turn

Stair width 900mm

From Previous we know15 Risers at 180

Length of 1st Flight = 2700 - 900Divide by Best Going = 1800/265

= 6.79Going Either 1800 /6 = 300mm 1800/7 = 257mm

257.14 is Closest to 265

Best Going 2R + G Between 550 to 700Midpoint = 625625- 2 x 180 = 265

Calculate StairConstrained Flight with Half Space Landing

Stair width 900mm Preferred Riser 170mm

3600/170 = 21.176

21 3600/21 = 171.429223600/22 = 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 = 286.36412- 3150/12 = 262.500Use 286.364



Rise 171.429mm

Going 286.364

Calculate StairConstrained Flight with Quarter Turn Winders


4100/170 = 24.118

24 4100/24 = 170.83325 4100/24 = 164

Use Rise 170.833

Best Going625 – 2R = BG

625 – 2 x 170.833 = 283.334

2650/ 283.334 = 9.353

92650/9 = 294.444 (USE)102650/10 = 265

Rise 170.833Going 268.75

Calculate StairConstrained Flight with Quarter Turn Winders


4100/170 = 24.118

24 4100/24 = 170.83325 4100/24 = 164

Use Rise 170.833

Best Going625 – 2R = BG

625 – 2 x 170.833 = 283.334

2650/ 283.334 = 9.353

92650/9 = 294.444 (USE)102650/10 = 265

Rise 170.833Going 294.444



3400/170 = 203400/20 = 170 Rise

Best Going = 625 – 2R = 625 – 2 x

170 = 285

2400/285 = 8.421

8 2400/8 = 300 (15 Diff)92400/9 = 266.667 (18.3 Diff)

Rise 170Going 300



3400/170 = 203400/20 = 170 Rise

Best Going = 625 – 2R = 625 – 2 x

170 = 285

2400/285 = 8.421

8 2400/8 = 300 (15 Diff)92400/9 = 266.667 (18.3 Diff)

Rise 170Going 300

With all examples either answer will comply and you should consult with your client and/or Architect

Determine Steel Square Mathematically

40mm Margin


Zoom In

Stair Pitch = 29.54⁰


Margin Line

Stair Pitch = 29.54⁰


This angle must be the same Stair Pitch = 29.54⁰



Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ XX = 40 ÷ Sin 29.54X = 81.131



Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ XX = 40 ÷ Sin 29.54X = 81.13


Set Out For Steel Square GoingGoing + Margin ÷ Sin Ѳ= 300 + 40 ÷ Sin 29.54⁰= 381.13mm

Ѳ


Set Out For Steel Square Rise

Ѳ



Ѳ

This Angle must = 90 - 29.54



Ѳ

This Angle must = 90 - 29.54This Angle must = 29.54⁰

Y = 40 ÷ Cos 29.54⁰Y = 45.9763



Ѳ

Rise + Margin ÷ Sin Ѳ= 170 + 40 ÷ Sin 29.54⁰= 170 + 45.98= 215.98

staircases bcgca3016b. types of stairs straight open riser dogleg closed riser definition –...

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