By Prof.Kuldeep Nayi Sub : Building Construction (2130607) STAIRS

STAIRS AND STAIRCASES -In every building, some arrangement should be made to provide access to its different floors and roof. -These levels are connected for communication by any of the following methods: 1> Ladders 2> Steps-stair 3> Escalators 4> Lifts 5> Ramps and chutes 6> Trolley-rope ways

Stairs and Stair case: A series of steps which provides access from one floor to another is called a stair, and the part of the building accommodating the stair is known as Stair Case. > A Stair may be constructed with steps either rising continuously or with a break in the form of landing in between. > All the steps should be so designed and constructed that up and down movement can be made with ease, comfort, quickness and safety. > The Stairs can be of any suitable material.

> Classification of stairs acc > Classification of stairs acc. to material used > WOODEN STAIRS > STONE STAIRS > METAL STAIRS > R.C.C. STAIRS > BRICK STAIRS

Wooden Stairs: It consists of wooden members Wooden Stairs: It consists of wooden members! > It also consists of various members such as: Strings or Stringers, Treads, Risers and Nosing. > Treads and Risers are jointed by tongued and grooved joints, which are further housed in or fixed to the strings to form steps of a flight

> Nosing projection should be 15 mm and not more than the thickness of the tread in any case > The Scota or other ornamental mouldings can be provided under the projection of nosing

Stone Stairs: The Stairs constructed of specially dressed Stone Blocks or Slabs are called Stone Stairs > These are more Durable, Hard, Fire-Resistant and Simple in construction > They are not liable to Decay > They are commonly used as External Stairs leading from the Ground level to the Entrance of a building at Ground floor > They are also used as approaches to Basement, Heating Chambers etc. > They are formally used in Commercial and Public buildings

Metal Stairs: The Stairs having different members made of Steel or Cast Iron are known as Metal Stairs > In these Stairs, The Strings are usually in the form of Steel Channels or Plates > The Treads consist of Checkered or Steel Plate, Concrete or Stone Slabs, fixed at their ends to the Strings by means of Angle Iron by Rivets or Welding > These Steps are suitable where rough Wear and Tear and Fire-proof qualities are required like Factories, Godowns etc.

The Treads of Metal Stair can be constructed of: 1) Metal Stair with Checkered Plate or Conc. Slab: > It consists of Steel Strings of Channels or Troughs with Checkered Plate Treads as shown: 2) Metal Stair with Steel Plate & Stone Slab Treads > In this, the Treads are of Steel Plates > The Stone and Marble Treads can also be used as shown:

3) Metal Stair with Concrete Steps: In this Stair, the Stringers are of Steel and Steps constructed of Concrete as shown: > The Steps are finished with Metal Nosing

4) Spiral Stair: The Metal Stair consisting of a central pipe Newel fixed with C.I. Steps around it in a Spiral form is known as Spiral Stair as shown: > The Treads are of Checkered Plate Treads for safety and can be of Precast or Cast-in-situ Treads > Used on Terraces, small Space and Lesser Traffic

Concrete Stairs: The Stairs constructed of Cement Concrete, Plain or Reinforced, are called Concrete Stairs Concrete Stairs are of two following types 1) Plain Concrete Stairs 2) R.C.C. Stairs

1) Plain Concrete Stairs: The Concrete Stairs constructed of Precast Concrete blocks or Cast-in-situ Cement Concrete without using Reinforcement are known as Plain Concrete Stairs > The Steps are mostly of Spandril type and are supported as in case of Stone Stairs > These Stairs are constructed in place of Stone Stairs and are mainly used at entrances to the buildings these days

2) R.C.C. Stairs: The Stairs constructed of Reinforced Cement Concrete are known as R.C.C. Stairs > The Steps are usually finished with Non-slippery material as Tiles, Terrazzo, Marble or other finish for pleasing appearance > For this, checkered grooves may be provided on it > The nosing is prevented to damage by fixing Brass, Iron castings or by embedding G.I. pipe at the nosing or paving the treads with Flag Stones as shown:

> Balusters are fixed into holes in treads by embedding them in Rich Cement Mortar

The Advantages of R.C.C. Stairs are: > Easy to construct into any geometrical shape > More durable, Fire-resistant and less noisy > Require comparatively thin sections > With suitable finish, provides pleasing appearance > Easy to wash and clean so provide better sanitation > They can be built of any complicated design The R.C.C. Stairs are further of Three types: 1) R.C.C. Slab and Beam type Stair 2) R.C.C. cantilever type Stair 3) R.C.C. Slab type Stair

1) R. C. C. Slab and Beam Type Stair: The R. C. C 1) R.C.C. Slab and Beam Type Stair: The R.C.C. Stair in which Steps are designed to act as slab between the Wall and a Stringer or between two Stringers is known as R.C.C. Slab and Beam Type Stair as shown:

2) R. C. C. Cantilever Type Stair: The R. C. C 2) R.C.C. Cantilever Type Stair: The R.C.C. Stair in which steps are cantilevered from the wall is known as R.C.C. Cantilever Type Stair

3) R. C. C. Slab Type Stair: The R. C. C 3) R.C.C. Slab Type Stair: The R.C.C. Stair in which each flight is designed and constructed as Inclined Slab is known as R.C.C. Slab Type Stair

Brick Stairs: The Stairs constructed of brick masonry are called Brick Stairs > This type of Stair can be made either Solid or provided with Arches to reduce the quantity of brickwork as shown: > The Treads of such Stairs are generally kept 1-1/2 brick in width and rise= two layers of bricks

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