Free Structural Analysis MCQs with Answers
78 Structural Analysis MCQs from Civil Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Structural analysis determines how beams, frames, trusses and arches carry loads through reactions, shear forces, bending moments, axial forces and deflections. It covers free-body diagrams, equilibrium equations, determinacy, influence lines and methods such as slope deflection, moment distribution and virtual work, while distinguishing analysis of a structure from its design.
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78 questions · page 2 of 4
- A. The noncollinear member carries zero force
- B. The collinear members carry equal compression
- C. All three members carry equal force
- D. The noncollinear member carries maximum force
Explanation: The noncollinear member is a zero force member because equilibrium at the joint cannot balance a force in its direction when no external…
Correct answer: The noncollinear member carries zero force- A. sum of member lengths at the joint
- B. sum of stiffnesses of members at the joint
- C. carry over factor of the joint
- D. fixed end moment at the joint
Explanation: The distribution factor allocates the unbalanced joint moment in proportion to member stiffness.
Correct answer: sum of stiffnesses of members at the joint- A. Sum of V v divided by GA
- B. Sum of M m L divided by EI
- C. Sum of N n L divided by AE
- D. Sum of P L cubed divided by EI
Explanation: For a truss, members primarily deform axially, so the unit load expression is the sum of N n L divided by AE.
Correct answer: Sum of N n L divided by AE24. A three hinged arch is classified as statically determinate because its internal hinge at the crown
- A. prevents all horizontal movement
- B. makes the arch behave as a beam
- C. eliminates the vertical reactions
- D. provides an additional equilibrium condition
Explanation: The zero moment condition at the crown hinge supplies an additional equation, allowing the reactions to be found from equilibrium alone.
Correct answer: provides an additional equilibrium condition- A. vertical jump at the section
- B. constant value over the span
- C. continuous parabolic shape
- D. zero value throughout the span
Explanation: The shear force changes abruptly as the moving load crosses the section, so its influence line has a vertical jump there.
Correct answer: vertical jump at the section- A. zero
- B. one
- C. two
- D. three
Explanation: A two hinged arch has one redundant horizontal reaction because the ordinary equilibrium equations do not determine all reactions.
Correct answer: one- A. area under the shear force diagram
- B. area under the bending moment diagram
- C. area under the M divided by EI diagram
- D. first moment of the load diagram
Explanation: The change in slope equals the area under the curvature diagram, which is M divided by EI.
Correct answer: area under the M divided by EI diagram- A. equal to the maximum span moment
- B. equal to the horizontal thrust
- C. zero only when the loading is symmetrical
- D. zero because the hinge cannot resist moment
Explanation: An ideal internal hinge cannot transmit bending moment, so the moment at the crown hinge is zero for any loading arrangement.
Correct answer: zero because the hinge cannot resist moment- A. first moment of the M divided by EI area
- B. area of the M divided by EI diagram
- C. average support reaction over the span
- D. maximum curvature multiplied by the span
Explanation: The second moment area theorem states that tangential deviation equals the first moment of the curvature diagram about the point of…
Correct answer: first moment of the M divided by EI area- A. pure bending with no axial force
- B. axial force caused by restrained expansion
- C. zero stress under every restraint condition
- D. torsion caused by thermal rotation
Explanation: A uniform temperature rise causes axial expansion rather than curvature.
Correct answer: axial force caused by restrained expansion- A. [d]{K} = {P}
- B. [P]{d} = {K}
- C. [K]{d} = {P}
- D. [K]{P} = {d}
Explanation: The global stiffness equation is [K]{d} = {P}, where [K] is the stiffness matrix, {d} is the displacement vector, and {P} is the applied…
Correct answer: [K]{d} = {P}- A. Unstable under its applied loading
- B. Plastic with unrestricted yielding
- C. Geometrically nonlinear with large rotations
- D. Linear elastic with small deformations
Explanation: Superposition is valid when load response is linear, which generally requires elastic material behavior and small deformations.
Correct answer: Linear elastic with small deformations- A. Bending moment changes sign
- B. Shear force becomes permanently zero
- C. Deflection reaches its maximum value
- D. Slope remains constant over the span
Explanation: At a point of contraflexure, the bending moment changes from sagging to hogging or vice versa.
Correct answer: Bending moment changes sign- A. One
- B. Three
- C. Two
- D. Six
Explanation: A fixed-ended plane beam has six reaction components, while only three independent equilibrium equations are available.
Correct answer: Three- A. Every support is converted into a fixed support
- B. All external loads are removed
- C. The redundant forces are released
- D. The member stiffnesses are made equal
Explanation: The selected redundants are removed or released so that the remaining structure becomes stable and statically determinate.
Correct answer: The redundant forces are released- A. Quarter-height of columns and beam midpoints
- B. Column bases and beam ends
- C. Top of columns and beam supports
- D. Mid-height of columns and midspan of beams
Explanation: The portal method commonly assumes points of contraflexure at the mid-height of columns and the midspan of beams.
Correct answer: Mid-height of columns and midspan of beams- A. Virtual work of the internal forces
- B. Total strain energy of the structure
- C. Kinetic energy of the moving loads
- D. Permanent deformation of the members
Explanation: Equilibrium requires the external virtual work to equal the internal virtual work for every compatible virtual displacement.
Correct answer: Virtual work of the internal forces- A. A unit load at i with all coordinates free
- B. A unit displacement at i with other coordinates fixed
- C. A unit rotation at every coordinate
- D. A unit displacement at another coordinate with i fixed
Explanation: Kii is the restoring force or moment at coordinate i produced by imposing a unit displacement at the same coordinate while all other nodal…
Correct answer: A unit displacement at i with other coordinates fixed- A. x/L
- B. x divided by L squared
- C. 1 minus x/L
- D. 1 minus x divided by L squared
Explanation: Equilibrium gives the left reaction as (L minus x) divided by L, which is 1 minus x/L.
Correct answer: 1 minus x/L- A. dV/dx = minus M squared
- B. dV/dx = M
- C. dM/dx = minus V squared
- D. dM/dx = V
Explanation: With the usual beam sign convention, the derivative of bending moment with respect to position equals the shear force, dM/dx = V.
Correct answer: dM/dx = V