A stair stringer is a structural member that is installed on either side or at the center of a flight of stairs in which treads and risers are fixed.
A beam-slab combination is economical; due to the aesthetic view, one beam without slab is provided with hanging steps i.e. cantilever on both sides of the beam.
Introduction to stair stringer:
The stringer is the structural part of a set of stairs.
In the case of RCC stairs, steps are constructed over stair slab that has width up to the full length of steps.
In Non-RCC stairs steel, wood, or composite materials are used in the stringer.
The most widely used material for these kinds of stairs in modern homes or architectural homes is metal, which needs to take a massive amount of loads.
Components of Stair Stringer:
Center Beam: This type of beam is provided at the centre of the staircase.
Landings: Landing is a floor area near a step up or down a ladder.
Risers: A riser is a vertical element in the staircase, which creates space between one step and the next step.
It is slightly inclined so that its top is closer to the base for the person climbing the stairs.
Steps: It consists of a tread (the horizontal part, where the foot will rest) and a riser (the vertical part).
Glass Railings: It is an attractive visual effect to create spaces to make the light flow feel more significant; it adds a great look and more value to the home and companies.
Types of stair stringer:
1. Single stair Stringer / Monobeam stair Stringer:
These are well known as single stringer stairs, or mono beam stairs were precisely cut.
Sheet metal is used as a main center structure to support the load with metal risers, steps and glass railings.
Consider the stair as a one-way slab in a long direction with a pin support at each end.
The reaction force transferred to the landing beam via shear and check the torsional capacity of the beam to resist minimum torsional compatibility if the beam and stair are reinforced concrete.
They are mostly used in modern homes; these can be straight, L-shaped or curved.
2. Double stair stringer or saw tooth stair stringer:
In Double stair stringer, we have two supports running from top to bottom.
The stringers are 6″ apart and usually situated at the center of the staircase, thick hardwood is used for steps.
Consider one-way slab in transversal direction to the edge beam and then the edge beam transferred the reaction force to the landing beam.
3. Routed stair Stringer or Housed Stair Stringer:
It consists of notches includes treads, risers, and wedges can be inserted also known as box stringers.
The notches are combined with the stringer to support the stairs treads.