STAIRS

STAIRS

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Stair

OVERVIEW

• Introduction

• Functional requirements

• Basic elements of stairs

• Type of stairs

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Stair

What is vertical movement or vertical circulation?

• Circulation is a movement of human and goods between

interior spaces in the building to the entrance or exit.

• Can be channeled through several types – passageway,

corridor, stairs, ramps, etc.

• Vertical circulation is movement of human and goods

between stories of a building.

• Classified into 2 classes;

• Class 1 system – ramps, staircase, elevators, escalators.

• Class 2 system – mainly not for human, e.g. dumbwaiters.

INTRODUCTION

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INTRODUCTION (cont.)

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STAIRS/STAIRWAY

• A set of steps formed to make it possible to pass to another

level on foot by putting one foot after the other on alternate

steps to climb up or down the stair.

• Stairs can be made of concrete, stone, wood, steel or

combination of any of these.


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Stair

LADDER

• A series of narrow horizontal steps fixed between two upright of

wood or metal, on which a person usually climbs up or climbs

down facing the ladder.

• Usually fixed in an upright, near vertical position or more at a shallow slope for ease of use. Therefore, it only occupy the least

floor area.

• Not suitable for elderly and handicapped and as a mean of

escape in case of fire.

• Should only be used for access to loft conversion of one room,

where there is not enough space for a stair, and that should be

fixed in position and fitted with handrails both sides.


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Stair

STEPLADDER

• A series of comparatively narrow, flat, horizontal steps, fixed

between two vertical upright, which provide more comfortable

and secure support for the foot than the slim.

RAMP

• A ramp is a surface, sloping uniformly as an inclined plane up

and down which a person may pass on foot between levels.

• Formed at a slope of at least 1:20. Thus, it occupies a

considerable area, usually adjacent to a long, low building.


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Stair

STRENGHT

• Able to support for movement between floors, including dead

and imposed load.

SAFETY IN USE

• Comply with the Building Regulation in determining the rise, thread, headroom and dimensions of the handrails and guarding.

• Should be constructed of materials that are capable of

maintaining strength and stability for a period of time sufficient to escape to the outside.

FIRE SAFETY

• The steps and the width should be adequate for the safe escape

to the outside.

FUNCTIONAL REQUIREMENTS

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PRIMARY FUNCTIONS

• Provide an access from one floor to another.

• Provide a safe means of travel between floors.

• Provide a degree of insulation where part of a separating

element between compartments in a building.

• Provide an easy mean of travel between floors.

• Provide a suitable means of escape in case of fire.

• Provide a mean of conveying fittings and furniture between

floor levels.

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STAIR TERMINALOGY

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STEPS

• A series of horizontal open

treads with a space between

the treads with a space

between the treads or as enclosed steps with a vertical

face between the treads.

• Tread – horizontal surface

of a step

• Riser – vertical surface or

near vertical of a step

STAIR TERMINALOGY

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Stair

FLIGHT

• Uninterrupted series of steps between floor and landing, or

between landing and landing.

• A flight should have no fewer than 3 steps and no more than

16 risers.

• The rise and tread in one flight and landings between floors

should be equal.

• The rise and tread should have the same size to avoid interruption in the rhythm of going up or down.

• The dimension of the riser and thread will determine whether

the stair is steep or shallow.

STAIR TERMINALOGY (cont.)

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Stair

FLIGHT (cont.)

• The dimensions will depends on the

function of the building and should

comply with the Building Regulation

(UBBL), e.g. Section 40.

• The steeper stair will save more space

and is accepted for houses because

the occupants are more familiar with

the stair.

• The shallow stair requires more area but

suitable for public building to minimise

danger to the public escaping via stair during emergency.


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Stair

HEAD ROOM

• A clearance height

between the pitch line of

the stair and the underside

of the stairs, landings and floors above the stair.

• Minimum 2 m clearance

from the pitch line for a

convenience of human

and goods movement.


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Baluster

• Vertical stand that supports

handrails for security purposes.

• Can be made from timber or

steel.

• Can be bolted to the sides of

flights or through the material,

grouted or set in mortices either cast or cut in the

material.


Handrail

• Horizontal member fixed on the

top of series of balusters.

• Can be made from timber or

steel.

Balustrade

• A series of baluster, capped by a handrail.

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Stair

Open railing

Closed railing


Stair

TYPE OF STAIRS

• Type of stairs:

o Straight flight/straight run

o Quarter turn/L-shaped

o Half turn (dog leg)/180 return

o Spiral (helical) & elliptical

o Winder

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Straight Flight Stair

• Rises from the floor to floor in

one direction with or without

an intermediate landing.

• Known as ‘cottage stair’ as well, commonly used in the

traditional ‘two-up two-down’

cottage.

• The most economical use of the straight flight is to locate

the stair in the centre of the

plan running for front to back.

TYPE OF STAIRS

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Quarter Turn Stair/

L-shaped

• Rises to a landing between

two floors, turns through 90˚,

then rises to the floor above.

• Good in compact planning.

• The quarter turn sometime

will be replaced with winders for economic use of space.

TYPE OF STAIRS (cont.)

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Half Turn (Dog Leg) Stair

• Rises to a landing between floors,

turns through 180˚, then rises

parallel to the lower flight to the

floor above.

• The most common arrangement

of stairs.

• Advantage – can be

constructed within the confined

vertical stair well.

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Stair

Spiral & Elliptical Stair

• Constructed as either a

spiral(helical) stair or an ellipse

stair.

• The most economical way to save space, but difficult to

use due to the sharp turns.

Very dangerous for the very

young and elderly.

• Usually use where the space is

very limited for access to an

intermediate floor of one room.

Elliptical stair

Spiral (helical) stair

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Winder Stair

• Triangular treads/tapered treads that

wind around quarter of half turn in place

of landings.

• To reduce the number of steps required in the rest of the stair and to economise

in space.

• Usually use in domestic stairs.

• Can be hazardous as they only offer little

foothold at the interior corner.

• Not recommended for public buildings in

the means of escape stairs especially for

the very young and elders.

TYPE OF STAIRS (cont.)

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Stairs can be made of :

• Timber

• Concrete – precast & cast-insitu

• Metal

• Stone

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Timber Staircase

• Constructed from timber board

• Common use in domestic work.

• The design of stairs flight landings or tapered steps is

depend on the space to accommodate it.

• Handrail balustrading is important to provide visual and practical safety barrier to the side of stairs.

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Tapered stairs/winder

• Frequently used because

can use space economically

Open tread stairs

• Closed string

• Cut strings or carriages

• Mono-carriage

• Alternating tread stairs

Timber Stair (cont.)

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Open riser stairs Closed riser stairs with housed stringer


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Alternating trade stairs

• Application – access to domestic loft

conversion only

• Very steep pitch – very economic

use of space

• Not very safe.

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Reinforced Concrete Staircase

• Can be cast in-situ, precast or combination of both.

• Better fire resistant from timber staircase.

• Common use in multi-storey building.

• Can be formed as straight flight, quarter turn, half turn or

geometrical. But, the usual form is half-turn.

• The construction of the staircase depends on the structural

of the building and the convenience in casting the stairs in

situ or the use of reinforced concrete support and precast

steps.

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Stair

TYPE OF STAIR (cont.)

In-situ RC stair

• Variety of stair types and arrangements are possible, which of

having its own appearance , characteristic and method of

construction.

• Common use as it is non-combustible, stronger and hardwearing.

• Will maintain its strength and integrity for a reasonable period

during an outbreak of fire. Therefore, it is more suitable than

timber stair as an escape route.

• Typical in-situ RC stairs are:

o Inclined slab stair

o Cranked slab stair

o String beam stair

o Cantilever stair31

Stair


Inclined slab stair

• Constructed when there are

LB wall around the stair.

• The landing is built into the

walls as one way span slab.

• The flight span from floor to

landing and landing to floor.

• Disadvantage – wasteful

cutting of brick or block to

allow the flight built into the

walls.

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Stair


Cranked slab stair

• The stair is constructed as a

cranked (bent) slab spanning

from landing to flight and to

landing with no side supports.

• This type of construction only

use when the landings can

not gain support each side of

stair.

• Disadvantage – more costly

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String and trimmer stair/String beam stair

• The landing beams are

supported by side walls (LB) or

the beams of the frame and

in turn support inclined beams that support the flight.

• Disadvantages - cause untidy

soffit or underside of the stair.

• Best suited for to the use of precast concrete steps and

precast landing.

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Cantilevered stair/cantilevered spine wall

• Constructed to cantilever

from the spine wall, or can

be partly cantilever from the

spine wall and supported by the enclosing frame or walls.

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Stair


Precast Concrete Stair

• Can be produced to most of the formats used for insitu RC stair.

• Seldom used because of the majority using cast in-situ method.

Common use for aesthetic reason.

• Advantages –

o good quality control of finished product

o no formwork thus no storage required and save the site

space

o stair can be installed at any time, thus the stair shaft can be

used for other purposes e.g. for lifting or hoisting space

o Hoisting, positioning and fixing of stair can be carried out by semi-skilled worker.

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Stair


Stone Stair

• Traditionally constructed using natural stone as the steps.

• Can be formed as:

o Rectangular/stepped soffit

o Flush soffit

• The end of the steps are built into the walls. The landings are

constructed using one or more large slab of natural stone built

into enclosing walls and bearing on the steps below.

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Stone Stair (cont.)

Stone steps with stepped soffit Stone steps with flush soffit

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Metal Stair

• Can be produced in cast iron, mild steel or aluminium alloy for

both external and internal used.

• Usually is custom made, therefore is more expensive.

• Steel channel section serves as stringer.

• Treads can be in the form of steel pan filled with concrete, steel flat plate with textured top surface or bar grating.

• Can be painted or covered with concrete for fire safety

reason.

• Advantage – no need formwork during construction.

• Disadvantage – regular maintenance in the form of painting.

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Metal Stair (cont.)

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Simple Reinforced

Concrete Stairs

Formwork

Reinforcement

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Metal stairs

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Timber Spiral Stair

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Precast Stairs – hoisting and assembling

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Precast Stair

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REFERENCES

1) R.Barry,1992, The Construction of Building,Vol. 2, 5th ed,

Blackwell Science Ltd.

2) Frederick S. Merritt et. al, 2001. Building Design and

Construction Handbook, 6th ed., McGraw Hill.3) Roy Chudley, et.al, 2005.Building Construction Handbook

,5th ed, Elsevier.

4) Francis D.K.Ching, 1991, Building Construction Illustrated,

2nd ed.,Van Nostrand Reinhold.

STAIRS

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