Details guidelines on RCC Staircase Design
RCC or reinforced concrete structures comprise of various building elements like Footings, Columns, Beams, Slabs, Staircase etc.
These elements are reinforced with steel to increase the strength of the structure. Staircase is considered as one such vital element in a RCC structure.
Given below, the details on several types of staircases and how the design is created for the dog-legged reinforced cement concrete staircase.
Stairs: There are lots of steps in a stair which are organized in a series to provide entry to various floors of a building. As a stair is the only medium for making communication among different floors of a building, the position of the stair should be perfect.
In a residential building, the staircase should remain adjacent to the main entrance.
In a public building, the stairs should be constructed from the main entrance itself and situated centrally, to give rapid entry to the main apartments.
There should be adequate lighting and suitable ventilation for all staircases.
Different types of Staircases - a. Straight stairs, b. Dog-legged stairs, c. Open newel stair and d. Geometrical stair
RCC Dog-legged Staircase design: In this type of staircase, the subsequent flights mount in opposite directions. The two flights in plan are not detached with a well. A landing is arranged in accordance with the level at which the direction of the flight varies.
Method for Dog-legged Staircase design: Depending on the direction along which a stair slab extents, the stairs are categorized into the following two types.
1. Stairs extending to the horizontal direction
2. Stairs extending to the vertical direction
Stairs extending to the horizontal direction: In these stairs, the support is provided at each side with walls. Stringer beams or at one side by wall or at the other side by a beam.
• Dead load of a step = ½ x T x R x 25
• Dead load of waist slab = b x t x 25
• Live load = LL (KN/m2)
• Floor finish = guess 0.5 KN/m
Stairs extending Longitudinally: In this type of stair, the beam is supported with top and at the bottom of flights.
• Self weight of a step = 1 x R/2 x 25
• Self weight of waist slab = 1 x t x 25
• Self weight of plan = 1 x t x 25[(R2 + T2)/T]
• Live load = LL (KN/m2)
• Floor finish = assume 0.5 KN/m
To make the design of an RCC stair perfect, initially, it is required to study different loads which will be enforcing on the stair.
From the load calculations, we can find out how much strength is necessary to bear the load. The load bearing strength of a staircase is based on the amount of steel and concrete applied.
The proportion of steel to concrete should be according to the standards. Steel in the staircase can withstand the tension enforced on it and the concrete deals with the compression.
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