250+ TOP MCQs on Design of Shear Reinforcement and Answers

Prestressed Concrete Structures Multiple Choice Questions on “Design of Shear Reinforcement”.

1. The ultimate shear resistance for any given section, vc should be least of values __________
a) v_cw and v_cf
b) v_ew and v_ef
c) v_rw and v_rf
d) v_dw and v_df
Answer: a
Clarification: At any given section, the ultimate shear resistance, v_c should be the least of values v_cw and v_cf where, v_{cw = ultimate shear resistance of section cracked in web, vcf = ultimate shear resistance of section cracked in flange.}

2. What should be provided if the shear force due to ultimate load is less than the shear force of the concrete?
a) Tensile reinforcement
b) Shear reinforcement
c) Principle reinforcement
d) Compressive reinforcement
Answer: b
Clarification: When V the shear force due to ultimate loads is less than the shear force of the concrete v_c, the shear force which can be carried by the concrete, a minimum shear reinforcement should be provided in the form of stirrups with spacing.

3. The spacing provided for shear reinforcement is given as __________
a) S_v = (A_sv0.87f_y/0.4b)
b) (A_sv0.91f_y/0.4b)
c) (A_sv0.12f_y/0.4b)
d) (A_sv0.23f_y/0.4b)
Answer: a
Clarification: The spacing provided for shear reinforcement S_v = (A_sv0.87f_y/0.4b), S_v = spacing of stirrups along the length of member, A_sv = cross sectional area of stirrup legs effective in shear, b = breadth (for T,I,L beams it is taken as breadth of rib, b_w).

4. When the shear force due to ultimate loads is less than 0.5 times shear force of concrete then shear reinforcement is?
a) Provided
b) Not provided
c) Made equal
d) Made zero
Answer: b
Clarification: When the shear force due to ultimate loads V is less than 0.5 times the shear force of concrete: (v < 0.5v_c)
Then no shear reinforcement is provided in the members of low importance.

5. When v > v_c condition exits, then the shear reinforcement provided includes which extra terms than actual spacing equation?
a) f_y, d_t, v, v_c
b) f_t, d_t, v, v_c
c) d_t, v, v_c
d) f_e, d_t, v, v_c
Answer: a
Clarification: When V exceeds V_c shear reinforcement is required conforming to the relation (V > V_c)
The extra terms used are f_y , d_t, v, v_c these are included in the spacing equation S_v
S_v = (A_sv0.87f_ydt / V-V_c).

6. The term dt in the spacing equation is termed as __________
a) Lowest value of depth
b) Neutral value of depth
c) Highest value of depth
d) Peak value of depth
Answer: c
Clarification: When v > v_c, the spacing provided in that:
d_t is the highest value of depth from the extreme compression fiber to longitudinal bars and depth from extreme compression fiber to centroid of tendons.

7. The spacing of stirrups for maximum shear stress is __________
a) 0.9d_t
b) 0.10d_t
c) 0.12d_t
d) 0.7d_t
Answer: d
Clarification: The spacing of stirrups should exceed neither 0.75d_t nor 4 times the web thickness of flanged members, for maximum shear stress the spacing of stirrups:
S_v > 0.75d_t = > x web thickness.

8. The maximum spacing (S_v)_max is provided for the condition is?
a) V > 1.8V_c
b) V > 1.5V_c
c) V > 2.0V_c
d) V > 3.5V_c
Answer: a
Clarification: When V exceeds 1.8V_c, the maximum spacing should be reduced to 0.5d_t, the lateral spacing of the individual legs of the stirrups provided at a cross section should not exceed 0.75d_t, if V > 1.8V_c, the maximum spacing is:
(S_v) max = 0.5 d_t.

9. The maximum shear stress value for M₃₅ and M₅₀ is?
a) 3.5 and 4.0
b) 3.7 and 4.6
c) 3.8 and 6.0
d) 4.2 and 4.0
Answer: b
Clarification: The maximum shear stress value for M₃₅ grade concrete is 3.7n/mm², the maximum shear stress value for M₅₀ grade concrete is 4.6n/mm², M₃₀ grade concrete is 3.5n/mm², M₄₀ grade concrete is 4.0n/mm², M₄₅ grade concrete is 4.3, M₅₅ grade concrete is 4.8n/mm².

10. The section should be redesigned if the nominal shear stresses __________
a) Exceeds the given values
b) Equal
c) Zero
d) Constant
Answer: a
Clarification: When the nominal shear stress, v/bd exceeds the maximum permissible shear stress values for the particular grades of concrete like M-30, M-35, M-40, M-45, M-50, M-55 and above then the section should be redesigned (this is according to table of maximum shear stress(n/mm²) (IS: 1343-1980).