Stairs and ramps are structures that bridge differences in level using a transport surface. Stairs are divided into equal steps to connect levels, while ramps bridge the height difference with flat surfaces rising in one direction.
Sizing
Ramp sizing:
With the correct dimensions, ramps can also be an essential element of barrier-free transport. The exact value of the required slope angle, width and height may vary by region or country, but the following values can be taken as guidelines:
Dimensions when designing a barrier-free ramp:
Sizing the staircase:
The floor-to-floor height and the construction rules for a comfortable staircase determine the rise and run of the steps, which also determine the length of the flight. To determine the step rise and the step run, use the formula 2 rises + 1 run = 60-64 cm. (different voice!) The number of steps is determined by dividing the floor to floor height by the step rise of your choice. The result of the division must be rounded upwards because the number of steps can only be an integer. A step rise of 15-17 cm with a width of 28-30 cm makes it comfortable for users.
Other proposed parameters:
-
The number of steps per flight may start from a minimum of 3 up to a maximum of 15. In exceptional cases, there could be a maximum of 20.
-
A flight of stairs may cover a maximum level difference of 1.8 m.
-
After every 10 to 14 steps (and after every 15 to 20 steps within a dwelling), a minimum 60-centimetre landing should be provided.
-
The headroom above the flight of stairs and landing shall be at least 2.2 m measured in the vertical plane of the walkline.
Form and structure:
The walking line of the flights of stairs or ramp on a ground plan line can be straight, curved, or a combination of the two. We can talk about one, two or multiple-flight stairs and ramps.
The typical forms of stairs with curved walklines are the single winder U-return and the spiral stairs. Their special feature is that they are designed with winders with partly or wholly contracting ground plan dimensions. The walkline of the winder stairs (with a minimum step run) is located off the centre line.
Structurally, stairs or ramps can lie on the ground or be supported by either walls or beams. The types of support can differ on sides, and a beam support may also run along the central axis of the flight, instead of any of the two sides. Supporting vaults or slabs can also be used to support the entire flight following its rise.
Cantilevered stairs use fixed-joint steps on one side but are unsupported on the other side. Another solution is to suspend the flight or ramp from the slab above.