In matrix stiffness method, the element stiffness matrix for a truss member is derived using:
A
Virtual work principle
B
Unit displacement method
C
Euler-Bernoulli beam theory
D
Plastic hinge concept
Correct Answer:
B. Unit displacement method
Element stiffness matrix is derived by applying unit displacements at nodes and calculating corresponding forces (unit displacement method).
The influence line for a reaction at support A of a simply supported beam AB is:
A
Triangular with ordinate 1 at A
B
Triangular with ordinate 1 at B
C
Linear with maximum ordinate at mid-span
D
Parabolic
Correct Answer:
A. Triangular with ordinate 1 at A
Influence line for reaction at A is triangular, varying from 1 at A to 0 at B, representing the reaction at A due to unit load.
In a two-hinged arch, the number of unknown reactions is:
Two-hinged arch has 2 supports (each with 2 reactions) = 4 unknowns total (horizontal and vertical at each hinge).
The bending moment diagram for a simply supported beam carrying a uniformly distributed load is:
A
Linear
B
Parabolic
C
Cubic
D
Hyperbolic
Correct Answer:
B. Parabolic
For UDL on simply supported beam, BMD is parabolic (second-degree curve) with maximum at center.
In Castigliano's theorem, the partial derivative of strain energy with respect to a force gives:
A
Slope at that point
B
Deflection in the direction of that force
C
Moment at that point
D
Stress at that point
Correct Answer:
B. Deflection in the direction of that force
Castigliano's first theorem states that ∂U/∂P = δ, where U is strain energy and δ is deflection in the direction of force P.
The deflection of a cantilever beam of length L carrying a point load W at the free end is:
A
WL³/(3EI)
B
WL³/(4EI)
C
WL⁴/(3EI)
D
WL⁴/(8EI)
Correct Answer:
C. WL⁴/(3EI)
For a cantilever beam with point load at free end, maximum deflection = WL⁴/(3EI). This is a standard formula in structural analysis.
In the method of sections, when analyzing a truss, the maximum number of members that can be cut in a single section is:
In the method of sections, we can cut maximum 3 members in a single section to ensure we have only 3 unknowns, which can be solved using 3 equilibrium equations (ΣFx=0, ΣFy=0, ΣM=0).
Self-compacting concrete (SCC) must achieve a slump flow of:
A
150-250 mm
B
300-500 mm
C
600-800 mm
D
900-1000 mm
Correct Answer:
C. 600-800 mm
SCC requires slump flow between 600-800 mm to flow and compact under its own weight without vibration.
Which of the following is a measure of concrete workability?
A
Slump test
B
Compressive strength test
C
Modulus of elasticity
D
Permeability test
Correct Answer:
A. Slump test
Slump test is the most common field test to measure the workability and flow characteristics of fresh concrete.
What is the recommended curing period for concrete in normal conditions?
A
3 days
B
7 days
C
14 days
D
28 days
Correct Answer:
C. 14 days
IS 456:2000 recommends minimum 14 days of moist curing for normal Portland cement in normal temperature conditions.
