GENERAL TERMINOLOGIES AND GUIDELINES AND DESIGN PARAMETERS FOR DESIGNING OF STAIRCASE.
in the process of Design of staircase, we should know certain terms and names to understand the process.
Some of the basic terminologies used in
staircase design are as follows
These terns are basic and simple to
understand with diagrams and we can observe this it in our day to day life.
Tread – the horizontal upper portion of a
step.
Raiser – the vertical portion of a step.
Raise – raise is a vertical distance
between two consecutive steps.
Flight – a series of steps provided between
two landings.
Landing – landing is nothing but the
horizontal slab provided between two flights.
Or landing is defined as the horizontal
slabs provided which connects the inclined waist slab of a typical staircase.
Waist – the least (minimum) thickness of
th3 staircase
Or we can say that the waist is also called
as waist slab where the steps are formed or constructed.
Waist slab is an inclined slab. Connecting
two landing or floor to landings.
Winder – radiating or angular tapering
steps.
Soffits – the bottom surface of the waist
slab or inclined slab between the two landings.
Nosing – the intersection of the tread and
the raiser.
More specifically it’s a top corner of the
steps or top nip of the steps where tread and raiser meet.
Classification of staircase.
The stairs are generally classified as follows.
1 stairs spanning parallel to the flight.
2 stairs spanning perpendicular to the
flight.
3 spherical staircase or cantilever
staircase.
Now further more in general stairs have
many types which are mentioned below.
1 Straight stairs
2 Dog legged stairs
3 Open newel or open well staircase
(Geometrical stairs such as circular stairs
or spiral stairs.)
In stair design there are certain important
thumb rules for fixing the dimensions of components of stairs like size of tread,
risers, etc....
Basically we have given some limitations
for deciding the size of stairs for better, efficient and comfortable human
experience.
This rules are applied in commercial and
residential projects as well.
1. for residential buildings
Raiser (R) = 150 mm to 180 mm
Tread (t) = 220 mm to 250 mm
2. For commercial buildings
Raiser (r) = 120 mm to 150 mm
Tread (t) = 250 mm to 300 mm
3. t+2r = 500 mm to 650 mm
i.e. sum of tread + 2 times raiser should
be equal to or between 500 mm to 650 mm
4. width of stairs,
For residential buildings = 0.8 m to 1 m
For commercial buildings = 1.8 m to 2 m
5. Width of landing = width of stairs
6. No. Of steps in each flight should be
less than 12 nos.
7. Pitch of the stair ways should be less
than 38°
8. The head room measured vertically above
any steps or below mid landing shall not be less than
2.1 m
9. Effective span
Below are certain simple explanation of
effective span (le) calculation for certain condition of staircase resting on
beam or other structures.
Effective span of stairs spanning parallel
to the flight.
Case one – when the stairs supported at the
top and bottom raisers by means of beams
Effective span – horizontal center to center
distance between supporting beams.
Case two – stairs supported by landing slab which spans perpendicular to the flight.
Effective span – going to stairs+ half the
width of landing of one side + half the width of landing on other side.
Note – the value is restricted to 1 m at
each end.
That
means if the half width value of a particular landing is more then one meter
then the value is taken as only 1 m.
Case three – when the landing slab is also
spans in the direction of flight.
Effective span – center to center distance
between walls or beams supporting the landing slab.
so hope you have all your doubts clear about what are the basic things we should know about stair case design.
these are the main points to remember at the time of design of staircase yet there are many more things to learn on this topic but some where we have to start and let me tell you these are the things which will help you in finding the practical life or site solution at the time of working as a civil engineer.
so hope you have all your doubts clear about what are the basic things we should know about stair case design.
these are the main points to remember at the time of design of staircase yet there are many more things to learn on this topic but some where we have to start and let me tell you these are the things which will help you in finding the practical life or site solution at the time of working as a civil engineer.
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