STAIRS

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Why do we need to learn about

Stairs

• Functional requirements

• Design considerations

• Types of Stairs

• Accessibility

• Circulation / Flow

• Fire escape

• Interconnectivity of

space

OBJECTIVES 1. State the functional requirements of stairs

2. Define the various terminology related to stairs

3. Identify the different forms of staircase construction and list the design considerations of staircases.

4. Describe the characteristics of different staircases and compare their advantages and disadvantages.

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Introduction

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Staircases provide a mean of access between different floor levels within a building

Functions of Stairs

• To allow normal access from floor to floor

• To allow escape from upper floors in the event of

fire

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1. Strength & stability

2. Fire Resistance

3. Sound Insulation

4. Aesthetics

Functional Requirement

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Shape

CLASSIFICATION

Materials

Straight

flight

Quarter

turn

Dog leg

Spiral

Timber

Concrete

Steel

Brick

Configuration of Staircases

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Configuration of Staircases

Straight Flight Stairs

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Quarter Turn Stairs

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Half Turn (dog-leg) Staircases

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Spiral Stairs

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Shape

CLASSIFICATION

Materials

Straight

flight

Quarter

turn

Dog leg

Spiral

Timber

Concrete

Steel

Brick

Timber Stairs

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Concrete Stairs

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Brick Stairs

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Metal Stairs

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Composite Stairs

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• combination of at least

two different materials

• made of concrete or steel

• composite stairs are steel

support with concrete or

timber treads

Components of A Staircase • Treads and Risers

• Strings

–Closed String

–Open or Cut String

• Landings

• Balustrades

–Open balustrade

–Closed balustrade

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Open Strings

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Cut to the profile of the treads and

risers to support them

Closed Strings

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Encloses the treads and risers which it

supports and top edge protrude 50-

63mm above nosing

Landings

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Handrail,Baluster & Newel Post

Newel post

Handrail

Baluster

Closed Balustrades

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Consists of framed or

unframed panels acting as

baluster to support the handrail

Open Balustrades

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Vertical balusters spaced at

certain interval to support the

handrail

Handrails &

Balustrades

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Stair Terminology Stair Terminology

Stair Terminology Stair Terminology

Basic Design Considerations

• The risers and treads within each flight of stairs shall be of uniform height and size.

• The height of a riser shall not be more than 175 mm. The width of a tread shall not be less than 275 mm. The width of a tread of any staircase in any residential unit shall not be less than 225mm. The width of a tread of any staircase in any industrial building shall not be less than 250mm. The width of the tread of any tapered step shall be taken as that when measured at a distance of 500mm from the narrower end.

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Tread

Riser

• The pitch of the stair shall be a maximum of 42°.

The clearance of headroom should not be less

than 2.0 m measured vertically above pitch line.

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Basic Design Considerations

• A landing shall be provided at every floor

level and door opening.

• Except for spiral staircases, an intermediate landing shall be provided in between floor levels at intervals of not more than 18 risers.

• The clear width of any landing, measured from the handrail or kerb (whichever protrudes further into the landing) to the wall or external railing of the landing, shall not be less than 900 mm

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Basic Design Considerations

Width of Stair & Landing (min 900mm)

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• A handrail shall be provided on at least one side of

the flight of staircase

• The height of the handrail shall be between 750mm

and 1000mm above the pitch line.

• Where there is a vertical drop in level of 1.0 m or

more (for a staircase with more than say 5 steps),

appropriate measures shall be taken to prevent

people from falling from a height. Where a barrier is

used to prevent falling from a height, the barrier shall

not have any feature that facilitates the climbing of

the barrier. The height of a barrier shall not be less

than 1.0 m. The height of a barrier at the flight of

stairs is measured vertically from the pitch line to the

top of the barrier.

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Basic Design Considerations

Handrails shall:

• have a circular section of

32mm to 50mm in diameter or

an equivalent gripping surface;

and

• have a clear space between

the handrail and all wall

surface –

– (i) not less than 40mm; or

– (ii) at least 60mm where

the wall has a rough

surface.

• A recess containing a handrail

shall extend at least 450mm

above the top of the rail

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Basic Design Considerations

For a flight of staircase,

a) In all buildings, except for industrial buildings, any

triangular opening or void formed around a tread,

riser and the bottom edge of the barrier, the size of

any opening or gap shall not be large enough as to

permit the passage of a sphere of a diameter of

150mm.

b) In all buildings, except for industrial buildings, the

gap size between any two consecutive steps shall

not be large enough as to permit the passage of a

sphere of a diameter of 100mm; and

c) In industrial buildings, the gap size between any

two consecutive steps shall not be large enough as

to permit the passage of a sphere of a diameter of

150mm.

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Basic Design Considerations

• Number of risers is not to exceed 18 in any flight of steps. Except for spiral, circular or geometric staircases, an intermediate landing shall be provided in between floor levels at intervals of not more than 18 risers.

• The width of landings should not be less than the width of the stairway.

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Basic Design Considerations

Concrete Staircases • Most common

• Advantages

– good fire resistance

– Strong

– better sound insulation

• Disadvantages

– Slow in erection – wet

process

– Proper training

required

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Requirements: – Concrete Grade 30 or above

– Minimum concrete cover 20 mm

– Waist thickness between 100 to 250mm

– Mild steel or high yield steel bars can be used as reinforcement

– Handrail to be at least 900 mm above the pitch line

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Concrete Staircases

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Concrete cover

Waist thickness

Min 900 mm

Hand-

railing

Concrete Staircases

Finishes – Warehouse – natural finishes. Add carborundum dust

/ rubber strips for slip resistance

– PVC tiles

– Rubber tiles

– Carpet mats

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Concrete Staircases

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Concrete Staircases

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Precast Staircases Advantages • Better quality

control

• Saving in site space

• Faster construction

• Installation is simple.

Disadvantages

• Requires mass production.

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Precast Concrete Treads

Precast Staircases

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Precast Staircases

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Precast Staircases

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