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By Dr. Attaullah Shah Swedish College of Engineering and Technology Wah Cantt. CE-401 Reinforced Concrete Design-II Design of Stair cases

A stairs is provided for vertical transportation between various floors of building. It is located in a room known as staircase. The stair should be centrally located in a building to provide easy access to all rooms. Stairs may be constructed of timber, brick, stones, steel or RCC. There may be more than one stairs in big building.

 A set of steps leading from one floor to the another floor is called stair. ..

steps-A step is comprised of a tread and a riser. Tread-It is upper horizontal portion of a step. TECHNICAL TERMS

Riser-It is vertical portion of step which provides support to the tread. Flight-It is continuous series of steps which provide support to the tread. Landing-A landing is provided at the top or bottom of a flights as level platform. It provides an opportunity to taking rest during the use of stair and facilitate change of direction. Rise-it the vertical distance between two successive treads. Nosing-It is the projecting part or the tread beyond the face of riser. Going-It is the horizontal distance between two successive riser faces. Pitch-It is the angle made by the stairs with the horizontal. String-It is slopping member supporting the steps in a stairs. Normally a west slab supports the steps. Newel post-It is vertical member provided at the each of flights to connect hand rail and ends of strings. Hand rail-A slopping member fixed on the top of balusters which is parallel to the string and may be used as a support by the person while using the stair. Head room- The minimum vrtical distance between the tread and ceiling of the staircase is called head room. Balusters-these are the vertical membersof wood metal supporting the hand rail. Soffit-Underside a stair.

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Stairway, staircase, stairwell, flight of stairs or simply stairs are names for a names construction designed to bridge a large vertical distance by dividing it into smallervertical vertical distances, called steps. Stairways may be straight, round, or may consist of two or more straight pieces connected at angles.

2 BACKSTAIRS DEFINITIONS  a second staircase at the rear of a building  Series of steps, or flights of steps and the landings leading from one level to another.

LADDERS  A structure consisting of a series of bars or steps between two upright lengths of wood, metal, or rope, used for climbing up or down something.  steps consisting of two parallel members connected by rungs; for climbing up or down

The Number of risers should be such odd numbers The staircase block should be towards the Southern or South-Western portion of the building A staircase located inside or outside the house should not be in the North-East corner of the building The steps, whether internal or external shall always be from North to South and from East to West StaircaseVastu

Measurements Stair measurements: The rise height or rise of each step is measured from the top of one tread to the next. It is not the physical height of the riser; the latter excludes the thickness of the tread. A person using the stairs would move this distance vertically for each step they take. The tread depth is measured from the edge of the nosing to the vertical riser. The going is measured from the edge of the nosing to the edge of nosing in plan view. A person using the stairs would move this distance forward with each step they take. The total run or total going of the stairs is the horizontal distance from the first riser to the last riser. It is often not simply the sum of the individual tread lengths due to the nosing overlapping between treads. The total rise of the stairs is the height between floors (or landings) that the flight of stairs is spanning. The slope or pitch of the stairs is the total rise divided by the total run (not the individual riser and treads due to the nosing). It is sometimes called the rake of the stairs. The pitch line is the imaginary line along the tip of the nosing of the treads. In the UK, stair pitch is measured in degrees from the horizontal. Headroom is the height above the nosing of a tread to the ceiling above it. Walk line - for curved stairs, the inner radius of the curve may result in very narrow treads. The "walk line" is the imaginary line some distance away from the inner edge on which people are expected to walk. Building code will specify the distance. Building codes will then specify the minimum tread size at the wal kline.

Location-stairs should be located such that it is easily accessible from different rooms and it well lighted and ventilated. Length of flight-Number of steps in any flight should not be less than3 and more than 12. Head room- it should not be less than 2.2m. Width of stair-stairs should be wide enough to avoid inconvenience of user. For domestic buildings minimum width of stair is 90cm& for public building 1.5m Pitch of stair-it should be between 30&45. Steps dimension- The proportioning of rise and tread should be such as to provide desired pitch of stair.

Thumb rule for rise and tread relation For providing comfort to the users the rise should be between 10 to 15cm &the tread between 25 to 30cm 2*rise in cm + going in cm=60 Rise in cm + going in cm=40to45 Using 14cm rise &30cm tread

Straight stair These stairs run straight between to floors and are used for small houses where available width is less. Itcan be single flight or more light landing.

Quarter turn stair In this change in direction either to the left or to right is provided by a quarter space landing or by winder. Winders are tapering steps, radiating from a point situated at center of newel Quarter turn provided at beginning and end of each flight.