What is the effective span of staircase, supported at each end by landing spanning parallel with the risers, if the width of landing is 2.5 m, width of starting passage is 1.5 m and going of the stair is 2.2 m?
What is the effective span of staircase, supported at each end by landing spanning parallel with the risers, if the width of landing is 2.5 m, width of starting passage is 1.5 m and going of the stair is 2.2 m? Correct Answer 3.95 m
Concept:
The effective span of the staircase, supported at each end by landing spanning parallel with the risers is calculated based on the length of half the width of landing and half the width of starting passage on either side of going of stairs.
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|
Item |
X |
Y |
Span (in metres) |
|
Case 1 |
< 1 m |
< 1 m |
G + X + Y |
|
Case 2 |
< 1 m |
> 1 m |
G + X + 1 |
|
Case 3 |
> 1 m |
< 1 m |
G + Y + 1 |
|
Case 4 |
> 1 m |
> 1 m |
G + 1 + 1 |
X - Half the width of starting passage
Y- Half the width of the landing
G – Going of stair
Calculation:
Given:
Width of landing = 2.5 m
Width of starting passage = 1.5 m
Half the width of landing = 1.25 > 1.
Half the width of starting passage = 0.75 <1
The given problem belongs to Case 2,
Hence Effective span = G + X + 1 = 2.2 + 0.75 + 1 = 3.95 m
