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WorksheetsDay 29-Oct 17-worksheet-PWD-Working stress method&PSC intro.
Total questions: 15
Worksheet time: 11mins
The modular ratio used in the working stress method partially accounts for the effect of —
Shrinkage of concrete
Elastic shortening
Creep of concrete
Fatigue of steel
For M 25 concrete, the permissible bending compressive stress σcbc as per WSM is —
6 N/mm²
8.5 N/mm²
9 N/mm²
11.5 N/mm²
In prestressed concrete, the force is transmitted to concrete by bond between steel and concrete in —
Post-tensioned system
Pre-tensioned system
Centrally tensioned system
Load-balanced system
A reinforced concrete column has 1 % steel and modular ratio = 10. The ratio of load carried by steel to that carried by concrete (Ps/Pc) is —
(a)
The critical depth of neutral axis for Fe 415 steel under WSM is —
0.40 d
0.289 d
0.253 d
0.33 d
In WSM, the stress–strain curve of concrete is assumed to be linear up to the permissible stress.
True
False
The modular ratio (m) decreases as the grade of concrete increases.
True
False
In direct tension, the permissible stress in concrete for M 20 grade =
(a)
Prestressing in which tendons are tensioned after concrete has hardened is called
(a)
For Fe 500 steel, the permissible stress in tension (σst) =
(a)
Load Balancing Method is most suitable for members with……………. cable profiles.
(a)
For M25 concrete (σcbc = 8.5 N/mm²), determine the modular ratio (m) used in the working stress method.
(a)
A reinforced concrete column has a net cross-sectional area of 250 cm², with 2 % steel reinforcement.
Assume modular ratio m = 13.
Find the percentage of total load carried by steel.
(a)
A rectangular pre-tensioned beam 250 mm × 500 mm carries a prestress force of 400 kN at 100 mm eccentricity.
If the bending moment due to external load is 50 kNm, find the stress at the top fiber.
(a)
In WSM, when the actual neutral axis depth is less than the critical depth, the section is —
(a)
