Correct Answer: B. Stair slab spanning longitudinally
Solution:
When a stair slab is supported at the top and bottom of a flight, it spans the horizontal distance between these supports. The load is transferred along the length of the stair, causing it to bend longitudinally. This is a common design for straight-flight stairs between two floors or landings.
Correct Answer: B. landing
Solution:
A landing is a level platform used to break up a long flight of stairs, to allow for a change in direction, or to provide a resting place.
Correct Answer: A. 2.1 m
Solution:
To prevent tall users from hitting their heads, building codes specify a minimum vertical clearance. A common standard for this headroom is around 2.1 meters (approx. 6 feet 8 inches), measured from the nosing line.
Correct Answer: A. Half turn stair
Solution:
A dog-legged stair consists of two straight flights running in opposite directions, separated by a half-space landing. This creates a 180-degree turn (a half turn).
Correct Answer: C. stringers
Solution:
The stringer (or stringer beam) is the structural component that runs along the side of a staircase, supporting the treads and risers.
Correct Answer: B. √(R² + T²)
Solution:
In this configuration, the step slab spans diagonally. The effective width for design purposes is calculated using the Pythagorean theorem, representing the diagonal length across the rise (R) and tread (T), which is √(R² + T²).
Correct Answer: C. open newel
Solution:
Open newel stairs typically have wider flights and more generous landings compared to more compact designs like dog-legged or spiral stairs, making them more comfortable and less steep to use.
Correct Answer: D. newel
Solution:
A newel post is the main structural post at the top, bottom, or turning point of a flight of stairs. It anchors the handrail and balustrade, providing stability to the entire railing system.
(i) String is the part of tread which is projecting beyond the face of the riser
(ii) Soffit is a sort of additional moulding provided under the nosing or tread to beautify the step in elevation
(iii) Baluster is a member supporting the handrail
(iv) Newel post is a vertical member at the ends of flights
Correct Answer: B. (i) and (ii)
Solution:
Statement (i) is incorrect; the projecting part of the tread is the 'nosing'. A 'stringer' is the inclined beam supporting the steps. Statement (ii) is incorrect; the 'soffit' is the underside of the staircase, while the moulding under a nosing is typically called a 'scotia'. Statements (iii) and (iv) are correct definitions.
Correct Answer: C. Quarter-Turn Stairs
Solution:
A quarter-turn stair changes its direction by 90 degrees (one right angle), typically by using a quarter-space landing or winders.
Correct Answer: C. 3.95 m
Solution:
According to IS 456, the effective span is the going plus, at each end, either half the width of the landing or one metre, whichever is smaller.
For the top landing: Width = 2.5 m, Half-width = 1.25 m. Since 1.0 m < 1.25 m, we take 1.0 m.
For the bottom landing (passage): Width = 1.5 m, Half-width = 0.75 m. Since 0.75 m < 1.0 m, we take 0.75 m.
Effective Span = Going + Value for top + Value for bottom = 2.2 m + 1.0 m + 0.75 m = 3.95 m.
Correct Answer: B. 19
Solution:
First, calculate the number of risers needed. Total height = 3 m = 3000 mm. Riser height = 150 mm. Number of risers = 3000 / 150 = 20 risers. The number of treads in a flight is always one less than the number of risers. So, Number of treads = 20 - 1 = 19.
Correct Answer: B. 30° to 45°
Solution:
For safety and comfort, the pitch or slope of a staircase should be between 30 and 45 degrees. Steeper stairs are difficult to climb, and shallower stairs take up too much space.
Correct Answer: C. 24
Solution:
Total height = 3.20 m = 320 cm. Riser height = 13 cm. Number of risers = 320 cm / 13 cm ≈ 24.61. Since we must have a whole number of risers, we'll use 25 risers (and adjust their height slightly). The number of treads is one less than the number of risers. Treads = 25 - 1 = 24.
Correct Answer: D. Newel Post
Solution:
This is the definition of a Newel Post. It's the main anchor post at the start, end, and turns of a staircase, providing the primary support for the handrail system.