Stairs (definition and dimensioning)

by PDF Civil Engineering
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The guidelines for the construction of stairs vary depending on the regulations. The requirements for the dimensions of the stairs are defined by standards. For apartment buildings with two apartments maximum the minimum useful width is 0.90 m and the height / depth ratio of 17/29.

In summary 

1- Definition:
2- Characteristic of a staircase:
3- Terminology of a staircase:
4- The elements to know for the calculation of a staircase:
5- Stairs with straight steps:

  • 5-1- DETERMINATION OF THE NUMBER N OF MARKET HEIGHTS:
  • 5-2- DETERMINATION OF THE HEIGHT OF THE MARKET:
  • 5-3- CALCULATION OF GIRON G:
  • 5-4- CALCULATION OF STAIRCASE RECOVERY:
  • 5-5- CALCULATION OF THE ESCAPE OF A STAIRCASE:

6- Guardrails and ramps:

  • 6-1- GUARDRAIL:
  • 6-2- RAMPS: 

1- Definition:

The staircase is a work consisting of a regular series of horizontal plans ( steps and landings ) allowing, in a construction, to pass on foot from one floor to another, it is also considered to be a work of vertical circulation.

2- Characteristic of a staircase:

A staircase is characterized by:

2. 1- General design of a staircase:

Straight staircase , screw in a turning area , etc.

The French staircase : its steps are carried, on the central day side, by a stringer in which they are embedded and, on the wall side, by a rack.
The English staircase has its steps supported by racks, with one end overhanging the day.
The staircase Italian is inserted staircase (encloses) between two walls.
The attached staircase has its steps embedded at one end in a wall.
The spiral staircase , or spiral, or spiral, has only radiating steps; it is either with central core, or with central day (or light).

2. 2- its composition :

wood, poured or precast concrete, metal, stone, marble or even glass.

2. 3- its steps :

They are square ( straight flights ), dancing or balanced ( stairways with revolving quarters ), or radiant ( spiral staircases ).

2.4- its dimensions:

  • the height of storey H to cross, or height from ground to ground.
  • the bench press, length L of the course of the stride line taken in the middle of the volleys or 50 cm from the ramp.
  • the inclination of the flights : it is 25 to 40 ° for an internal staircase .
  • step height and lap.

Experience proves that a staircase is pleasant if the values ​​of step height (h) and lap (g) correspond to this formula (de Blondel): 2 h + g = 0.64 m Escalators , or stairs rolling , are with mobile steps articulated on an endless chain driven by a motorized mechanism.

3- Terminology of a staircase:

terminology of a staircase

The step : useful width of the staircase , measured between walls or between stringers.
The step height: vertical distance which separates the top of a step from the top of the next step.
The heights of the steps of the interior stairs vary from 17 to 20 cm approximately.
In staircase dimensioning calculations , the height is often designated by
the letter H.
The fold: horizontal distance measured between the noses of two consecutive steps. The treads of the steps of the interior stairs vary from 27 to 32 cm approximately. In staircase design calculations , the lapis often designated by the letter G.
The riser: designates either the vertical face situated between two consecutive steps, or the piece of wood or metal closing the space between these two steps.
The step: flat surface of the staircase on which one steps to go up or down. By extension, the term also designates the piece of
wood or metal that receives the foot. The word “step” is also used to name the assembly formed by the step and the riser, particularly in the case of massive concrete stairs .