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Plan & Section of Open Well Stair

Please see the attached picture.

I want to find out the dead load per unit length and live load per unit length (both in kN/m), that will be acting on the floor beam (300 mm × 450 mm) and the landing beam (300 mm × 800 mm).

I need these values to be used as input in an ETABS model.

Also what portion of these two beams, shall be assigned those loads? I mean, for the landing beam, I think the load shall be assigned for full length, but in case of floor beam, I think the load shall be applied to the portion where the stair connects to the beams (stair width). Is this approach correct?

Fred
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HANZEL HARRY FERNANDEZ
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1 Answers1

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Assuming your staircase opening is one meter wide and the stairs are made of concrete , you have

$$\frac{4.2*1.2*1kN/m}{2*1.2}= 2.1kN/m$$

this sectional uniform load applies to the beginning and end of the landing beam in addition to $$ \frac{1m*1.2m* 1kN/m}{2}=0.6kN/m$$ this is the uniform load at the one-meter section of the landing beam. Then we have two additional concentrated loads imparted on the two stringers tributary of the 4 stairs on the two stringers which are $$ 0.3kN/m*3/4.2$$ This has to be repeated for the dead load of your Concrete slabs that you have the data on them. At the top and bottom end of the stairs the beams as you mention take half of the live and dead load continuously at one side of the beam, in addition to the tributary concentrated load of the 4 steps which is

$$0.3 kN/m *1.2/4.20$$for live load and similar factors used to calculate the dead load!

kamran
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