CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 1: In a staircase, the horizontal dimension of a step is 250mm and the vertical dimen-sion is 150mm. The horizontal part is called

(a) riser(b) tread(c) nosing(d) waist

Q 2: In a staircase, the horizontal dimension of a step is 250mm and the vertical dimen-sion is 150mm. The vertical part is called

(a) riser(b) tread(c) nosing(d) waist

Q 3: In a staircase, an edge part of the tread that protrudes over the riser beneath iscalled

(a) riser(b) tread(c) nosing(d) waist

Q 4: In a staircase, a flight is

(a) an uninterrupted series of steps(b) the total number of steps between floor to floor(c) the total number of steps in a multistoryed building(d) the length of rise and tread

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 5: In a staircase, the going is

(a) always equal to tread depth.(b) is equal to the sum of rise height and tread depth.(c) is the same as tread depth when there is no nosing.(d) always equal to rise height

Q 6: In a staircase, the number of steps is

(a) the number of treads.(b) the number of risers.(c) the sum of number of treads and risers.(d) the difference of treads and risers

Q 7: The floor to floor height of a building is 3.0m. The tread depth of a step is 250mmand the rise height of a step is 150mm. The total number of steps to be providedfor accessing next floor is equal to

(a) 18(b) 19(c) 20(d) 21

Q 8: The tread depth of a step is 250mm and the rise height of a step is 150mm. Takeunit weight of reinforced concrete as 25.0kN/m3. The weight of each step (withoutwaist) will be equal to

(a) 0.469kN per m width of staircase(b) 0.586kN per m width of staircase(c) 0.703kN per m width of staircase(d) 0.820kN per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 9: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. Take unit weightof reinforced concrete as 25.0kN/m3. The weight of each step (including waist) willbe equal to

(a) 1.172kN per m width of staircase(b) 1.562kN per m width of staircase(c) 1.953kN per m width of staircase(d) 2.343kN per m width of staircase

Q 10: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. The thicknessof floor finish is 15mm. Take unit weight of reinforced concrete as 25.0kN/m3 andunit weight of floor finish as 23.5kN/m3 The weight of each step (including waist)will be equal to

(a) 0.825kN per m width of staircase(b) 1.238kN per m width of staircase(c) 1.650kN per m width of staircase(d) 2.063kN per m width of staircase

Q 11: The tread depth of a step is 250mm, the going depth of a step is 250mm, andthe rise height of a step is 150mm. Take unit weight of reinforced concrete as25.0kN/m3. The weight of each step (without waist) will be equal to

(a) 1.875kN/m per m width of staircase(b) 2.344kN/m per m width of staircase(c) 2.812kN/m per m width of staircase(d) 3.281kN/m per m width of staircase

Q 12: The tread depth of a step is 250mm, and the rise height of a step is 150mm. Thewidth of staircase is 1200mm. The width of landing, provided in one side of theflight, is 1200mm. The floor to floor height is 3000.0m. The effective span of thestaircase is equal to

(a) 1.425m(b) 2.138m(c) 2.850m(d) 3.562m

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 13: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. Take unit weightof reinforced concrete as 25.0kN/m3. The weight of each step (including waist) willbe equal to

(a) 4.686kN/m per m width of staircase(b) 6.248kN/m per m width of staircase(c) 7.810kN/m per m width of staircase(d) 9.372kN/m per m width of staircase

Q 14: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. The thicknessof floor finish is 15mm. Take unit weight of reinforced concrete as 25.0kN/m3 andunit weight of floor finish as 23.5kN/m3 The weight of each step (including waist)will be equal to

(a) 3.300kN/m per m width of staircase(b) 4.951kN/m per m width of staircase(c) 6.601kN/m per m width of staircase(d) 8.251kN/m per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Answers1. (b) tread

2. (a) riser

3. (c) nosing

4. (a) an uninterrupted series of steps

5. (c) is the same as tread depth when there is no nosing.

6. (b) the number of risers.

7. (c) 20

8. (a) 0.469kN per m width of staircase

9. (b) 1.562kN per m width of staircase

10. (c) 1.650kN per m width of staircase

11. (a) 1.875kN/m per m width of staircase

12. (c) 2.850m

13. (b) 6.248kN/m per m width of staircase

14. (c) 6.601kN/m per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Questions with solutionQ 1: In a staircase, the horizontal dimension of a step is 250mm and the vertical dimen-

sion is 150mm. The horizontal part is called

(a) riser(b) tread(c) nosing(d) waist

Explanation: In a staircase, the horizontal part is called tread.

Answer : 1. (b) tread

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 2: In a staircase, the horizontal dimension of a step is 250mm and the vertical dimen-sion is 150mm. The vertical part is called

(a) riser(b) tread(c) nosing(d) waist

Explanation: In a staircase, the vertical part is called riser.

Answer : 2. (a) riser

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 3: In a staircase, an edge part of the tread that protrudes over the riser beneath iscalled

(a) riser(b) tread(c) nosing(d) waist

Explanation: In a staircase, when nosing is present, measured horizontally, the total"run" length of the stairs is not simply the sum of the tread lengths, as the treadsoverlap each other.

Answer : 3. (c) nosing

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 4: In a staircase, a flight is

(a) an uninterrupted series of steps(b) the total number of steps between floor to floor(c) the total number of steps in a multistoryed building(d) the length of rise and tread

Explanation: In a staircase, a flight is an uninterrupted series of steps.

Answer : 4. (a) an uninterrupted series of steps

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 5: In a staircase, the going is

(a) always equal to tread depth.(b) is equal to the sum of rise height and tread depth.(c) is the same as tread depth when there is no nosing.(d) always equal to rise height

Explanation: In a staircase, when nosing is present, measured horizontally, the total"run" length of the stairs is not simply the sum of the tread lengths, as the treadsoverlap each other.

Answer : 5. (c) is the same as tread depth when there is no nosing.

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 6: In a staircase, the number of steps is

(a) the number of treads.(b) the number of risers.(c) the sum of number of treads and risers.(d) the difference of treads and risers

Explanation: In a staircase, the number of steps is always the number of risers,not thenumber of treads.

Answer : 6. (b) the number of risers.

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 7: The floor to floor height of a building is 3.0m. The tread depth of a step is 250mmand the rise height of a step is 150mm. The total number of steps to be providedfor accessing next floor is equal to

(a) 18(b) 19(c) 20(d) 21

Solution:(i) Floor to floor height, H=3000.0 mm

(ii) Tread depth of step, T=250.0 mm

(iii) Rise height of step, R=150.0 mm

(iv) Number of steps=20

Answer : 7. (c) 20

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 8: The tread depth of a step is 250mm and the rise height of a step is 150mm. Takeunit weight of reinforced concrete as 25.0kN/m3. The weight of each step (withoutwaist) will be equal to

(a) 0.469kN per m width of staircase(b) 0.586kN per m width of staircase(c) 0.703kN per m width of staircase(d) 0.820kN per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Rise height of step, R=150.0 mm

(iii) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(iv) Weight of each step(without waist), wstep=1

2γrcRT=1

2 × 25.0× 0.150× 0.250=0.469 kN

Answer : 8. (a) 0.469kN per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 9: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. Take unit weightof reinforced concrete as 25.0kN/m3. The weight of each step (including waist) willbe equal to

(a) 1.172kN per m width of staircase(b) 1.562kN per m width of staircase(c) 1.953kN per m width of staircase(d) 2.343kN per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Going length of step, G=250.0 mm

(iii) Rise height of step, R=150.0 mm

(iv) Depth of waist slab, D=150.0 mm

(v) Length of step along waist slab, Bw

=√R2 + T 2

=√

0.1502 + 0.2502

=291.5 mm(vi) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(vii) Weight of each step(without waist), wstep=1

2γrcRT=1

2 × 25.0× 0.150× 0.250=0.469 kN

(viii) Weight of waist for each step, wwaist=γrcDBw

=25.0× 0.150× 0.292=1.093 kN

(ix) Weight of each step(including waist), wsw=wstep + wwaist=0.469 + 1.093=1.562 kN

Answer : 9. (b) 1.562kN per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 10: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. The thicknessof floor finish is 15mm. Take unit weight of reinforced concrete as 25.0kN/m3 andunit weight of floor finish as 23.5kN/m3 The weight of each step (including waist)will be equal to

(a) 0.825kN per m width of staircase(b) 1.238kN per m width of staircase(c) 1.650kN per m width of staircase(d) 2.063kN per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Going length of step, G=250.0 mm

(iii) Rise height of step, R=150.0 mm

(iv) Depth of waist slab, D=150.0 mm

(v) Length of step along waist slab, Bw

=√R2 + T 2

=√

0.1502 + 0.2502

=291.5 mm(vi) Thickness of floor finish, tff=15.0 mm

(vii) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(viii) Unit weight of floor finish, γff=23.5 kN/m3

(ix) Weight of each step(without waist), wstep=1

2γrcRT=1

2 × 25.0× 0.150× 0.250=0.469 kN

(x) Weight of waist for each step, wwaist=γrcDBw

=25.0× 0.150× 0.292=1.093 kN

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

(xi) Weight of floor finish for each step, wff=γrctffT=23.5× 0.015× 0.250=0.088 kN

(xii) Weight of each step(including waist and floor finish), wswf=wstep + wwaist + wff=0.469 + 1.093 + 0.088=1.650 kN

Answer : 10. (c) 1.650kN per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 11: The tread depth of a step is 250mm, the going depth of a step is 250mm, andthe rise height of a step is 150mm. Take unit weight of reinforced concrete as25.0kN/m3. The weight of each step (without waist) will be equal to

(a) 1.875kN/m per m width of staircase(b) 2.344kN/m per m width of staircase(c) 2.812kN/m per m width of staircase(d) 3.281kN/m per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Rise height of step, R=150.0 mm

(iii) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(iv) Weight of each step(without waist), wstep=1

2γrcRT=1

2 × 25.0× 0.150× 0.250=0.469 kN

(v) Weight of each step(without waist) per m, wstepm=

12γrcRT

G

=12 ×25.0×0.150×0.250

0.250=1.875 kN/m

Answer : 11. (a) 1.875kN/m per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 12: The tread depth of a step is 250mm, and the rise height of a step is 150mm. Thewidth of staircase is 1200mm. The width of landing, provided in one side of theflight, is 1200mm. The floor to floor height is 3000.0m. The effective span of thestaircase is equal to

(a) 1.425m(b) 2.138m(c) 2.850m(d) 3.562m

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Rise height of step, R=150.0 mm

(iii) Width of landing, Bl=1200.0 mm

(iv) Floor to floor height, H=3000.0 mm

(v) Number of steps in each flight=10

(vi) Width of landing, Bl=1200.0 mm

(vii) Length of flight, Lf=(Nf,step − 1)G=(10− 1)× 0.250=2.250 m

(viii) Effective length of staircase, Lef=Lf + Bl

2 or Lf + 1.0m whichever is less=2.250 + 0.600=2.850 m

Answer : 12. (c) 2.850m

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 13: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. Take unit weightof reinforced concrete as 25.0kN/m3. The weight of each step (including waist) willbe equal to

(a) 4.686kN/m per m width of staircase(b) 6.248kN/m per m width of staircase(c) 7.810kN/m per m width of staircase(d) 9.372kN/m per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Going length of step, G=250.0 mm

(iii) Rise height of step, R=150.0 mm

(iv) Depth of waist slab, D=150.0 mm

(v) Length of step along waist slab, Bw

=√R2 + T 2

=√

0.1502 + 0.2502

=291.5 mm(vi) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(vii) Weight of each step(without waist) per m, wstepm=

12γrcRT

G

=12 ×25.0×0.150×0.250

0.250=1.875 kN/m

(viii) Weight of waist for each step per m, wwaistw=γrcDBw

G

=25.0×0.150×0.2920.250

=4.373 kN/m(ix) Weight of each step(including waist) per m, wswm

=wstepm + wwaistm=1.875 + 4.373=6.248 kN/m

Answer : 13. (b) 6.248kN/m per m width of staircase

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

Q 14: The tread depth of a step is 250mm, the going depth of a step is 250mm, the riseheight of a step is 150mm and the depth of waist slab is 150mm. The thicknessof floor finish is 15mm. Take unit weight of reinforced concrete as 25.0kN/m3 andunit weight of floor finish as 23.5kN/m3 The weight of each step (including waist)will be equal to

(a) 3.300kN/m per m width of staircase(b) 4.951kN/m per m width of staircase(c) 6.601kN/m per m width of staircase(d) 8.251kN/m per m width of staircase

Solution:(i) Tread depth of step, T=250.0 mm

(ii) Going length of step, G=250.0 mm

(iii) Rise height of step, R=150.0 mm

(iv) Depth of waist slab, D=150.0 mm

(v) Length of step along waist slab, Bw

=√R2 + T 2

=√

0.1502 + 0.2502

=291.5 mm(vi) Thickness of floor finish, tff=15.0 mm

(vii) Unit weight of reinforced concrete, γrc=25.0 kN/m3

(viii) Unit weight of floor finish, γff=23.5 kN/m3

(ix) Weight of each step(without waist) per m, wstepm=

12γrcRT

G

=12 ×25.0×0.150×0.250

0.250=1.875 kN/m

(x) Weight of waist for each step per m, wwaistw=γrcDBw

G

=25.0×0.150×0.2920.250

=4.373 kN/m

CE23 : Design of RC Structures Assignment-10 July-October, 2017 : Week-10

(xi) Weight of floor finish for each step per m, wffm=γrctffT

G

=23.5×0.015×0.2500.250

=0.352 kN/m(xii) Weight of each step(including waist and floor finish) per m, wswfm

=wstepm + wwaistm + wffm=1.875 + 4.373 + 0.352=6.601 kN/m

Answer : 14. (c) 6.601kN/m per m width of staircase