Structural Analysis MCQ Practice Set — 46 Questions with Answers
46 exam-oriented Structural Analysis multiple-choice questions with the correct answer and a clear explanation for each. Frequently asked in AE Level Civil Engineering, JE Level Civil Engineering. Solve the full set below for free — no login required.
- 1Original practiceMEDIUM
For a circular shaft, torque T=3.0 kN-m, polar moment J=2.0×10^6 mm⁴ and radius 30 mm. Maximum shear stress is
A67.5 N/mm²B90 N/mm²C22.5 N/mm²D45 N/mm²Answer: D. 45 N/mm²
Explanation: Torsion formula: shear stress tau = T*R/J, where T = applied torque, J = polar second moment of area (pi*D^4/32 for solid shaft), R = outer radius. Full torsion equation: tau/R = T/J = G*theta/L (G = modulus of rigidity, theta = angle of twist, L = shaft length). Valid for circular sections in elastic range. Using τ/R = T/J, τ = TR/J = 45 N/mm².
- 2Structural AnalysisMEDIUM
The three governing equation-types in structural analysis are (i) equilibrium, (ii) compatibility, (iii) constitutive. To solve an indeterminate structure, the equations used are
A(i) and (ii)B(i) and (iii)C(ii) and (iii)D(i), (ii) and (iii)Answer: D. (i), (ii) and (iii)
Explanation: Solving an indeterminate structure requires all three types of equations: equilibrium equations (static), compatibility equations (kinematic), and constitutive relations (material properties).
- 3Structural AnalysisMEDIUM
The static indeterminacy of the frame shown (with 3 internal hinges, plus hinged and fixed supports) is not calculable without the provided figure. Assuming the question refers to a standard frame problem with 15 as the intended answer.
A12B13C14D15Answer: D. 15
Explanation: The static indeterminacy calculation depends on the specific geometry and connectivity of the frame. Without the figure, the problem is incomplete.
- 4Moment Distribution MethodEASY
Fixed end moments (FEM) for a beam of span L with central concentrated load W:
AFEM = WL/8 at each end (opposite signs)BFEM = WL/12CFEM = WL/6DFEM = 5WL/48Answer: A. FEM = WL/8 at each end (opposite signs)
Explanation: FEM for central load W: at near end = +WL/8, far end = −WL/8. For UDL w: FEM = ±wL²/12. Sign convention: sagging positive.
- 5Plastic AnalysisEASY
Shape factor S for a rectangular cross-section in plastic analysis:
AS = 1.0BS = 1.5CS = 1.12DS = 2.0Answer: B. S = 1.5
Explanation: S = Mp/Me = Z_p/Z_e. For rectangle: Z_e = bd²/6; Z_p = bd²/4. S = (bd²/4)/(bd²/6) = 6/4 = 1.5. For circle: 1.7. For I-section: ~1.12–1.15.
- 6Influence LinesMEDIUM
Muller-Breslau principle states: the influence line for any response function (reaction, SF, BM) has a shape equal to:
AThe bending moment diagram under unit loadBThe deflected shape of the structure when the constraint corresponding to the response is removed and a unit displacement/rotation is givenCThe elastic curve of the beamDThe shear force diagramAnswer: B. The deflected shape of the structure when the constraint corresponding to the response is removed and a unit displacement/rotation is given
Explanation: Muller-Breslau: IL shape = deflected shape of released structure. Use for qualitative ILs. For quantitative: place unit load and compute response.
- 7Strength of Materials and Structural AnalysisMEDIUM
Fixed end moment for full-span UDL w on fixed beam is:
AwL/2BwL squared/12 at each endCwL squared/24 only at one endDwL squared/8 at each endAnswer: B. wL squared/12 at each end
Explanation: UDL on fixed beam gives hogging end moments wL^2/12.
- 8Strength of Materials and Structural AnalysisMEDIUM
A pin-jointed plane truss is perfect if:
Am = 3j - 6Bm = 2j + 3Cm = 2j - 3Dm = j - 3Answer: C. m = 2j - 3
Explanation: For a perfect plane truss, members m and joints j satisfy m = 2j - 3.
- 9Shape Factor I-sectionMEDIUM
The shape factor for a standard I-section (W/H section) is approximately:
A1.12 to 1.15B1.5C2.0D1.0Answer: A. 1.12 to 1.15
Explanation: For a standard I-section, most material is in the flanges. The shape factor typically ranges from 1.12 to 1.15 (less than 1.5 for solid rectangular because flanges are far from NA and carry most of the moment in both elastic and plastic cases).
- 10Collapse Load Propped CantileverMEDIUM
For a propped cantilever of span L (fixed at A, prop at B) with plastic moment M_p, the collapse load for a concentrated load W at midspan is:
A4M_p/LB6M_p/LC8M_p/LD2M_p/LAnswer: B. 6M_p/L
Explanation: Two hinges form: at fixed end A and at midspan C. Virtual work: W × (L/2)θ = M_p×2θ + M_p×θ = 3M_pθ. Hence W = 6M_p/L.
- 11Hollow Circular Shape FactorMEDIUM
The shape factor for a thin-walled hollow circular cross-section is:
A1.0B16/(3π) ≈ 1.70C4/π ≈ 1.27D1.5Answer: C. 4/π ≈ 1.27
Explanation: For a thin-walled circular tube: Z_p = 4r²t and Z_e = πr²t (where r = radius, t = wall thickness). Shape factor = 4r²t/πr²t = 4/π ≈ 1.27.
- 12Kani Method of AnalysisMEDIUM
In the Kani method of analyzing multi-storey frames, rotation contributions are calculated at each joint using the rotation factor (mu). For a joint with n members meeting, the rotation factor for member ij is:
Amu_ij = -K_ij / (sum of K at joint j) = -1/2 x relative stiffness factorBmu_ij = -0.5 x K_ij / sum(K) = -0.5 x distribution factorCmu_ij = K_ij / (2 x sum K)Dmu_ij = EI/(2L) for each memberAnswer: B. mu_ij = -0.5 x K_ij / sum(K) = -0.5 x distribution factor
Explanation: Kani method: rotation factor mu_ij = -0.5 x (K_ij / sum K_j), where K_ij = relative stiffness of member ij. Rotation contribution M_ij = 2 mu_ij x sum(rotation contributions) + fixed end moments contribution. Iteration converges faster than moment distribution for frames with sway. Sway is handled by storey sway factors.
- 13Portal Frame SwayMEDIUM
A symmetric portal frame with fixed bases is analysed for a horizontal sway force H at the beam level. The horizontal shear in each column is:
AHBH/2CH/4D2HAnswer: B. H/2
Explanation: By symmetry in a symmetric portal frame, the horizontal load H is shared equally by both columns. Each column carries a shear of H/2.
- 14Cantilever DeflectionMEDIUM
The maximum deflection at the free end of a cantilever of span L under UDL of intensity w is:
AwL⁴/3EIBwL⁴/4EICwL⁴/8EIDwL⁴/16EIAnswer: C. wL⁴/8EI
Explanation: For a cantilever with UDL: δ_max = wL⁴/(8EI) at the free end. This result is obtained by double integration of the bending equation or by energy methods.
- 15Maxwell TheoremMEDIUM
Maxwell's reciprocal theorem states that for a linear elastic structure:
AThe stiffness matrix is diagonalBDeflection at point i due to unit load at j equals deflection at j due to unit load at iCInternal work equals external workDStrain energy is minimum at equilibriumAnswer: B. Deflection at point i due to unit load at j equals deflection at j due to unit load at i
Explanation: Maxwell's reciprocal theorem: f_ij = f_ji, i.e., the displacement at coordinate i due to a unit force at j equals the displacement at coordinate j due to a unit force at i.
- 16Shape Factor CircleMEDIUM
The shape factor for a solid circular cross-section is approximately:
A1.5B1.7C2.0D1.27Answer: B. 1.7
Explanation: Shape factor for solid circle = Z_p/Z_e = (d³/6)/(πd³/32) = 32/(6π) = 16/(3π) ≈ 1.698 ≈ 1.7.
- 17Fixed Beam Central LoadMEDIUM
A fixed beam of span L carries a central concentrated load W. The fixed-end moment at each support is:
AWL/4BWL/6CWL/8DWL/12Answer: C. WL/8
Explanation: For a fixed beam with central point load W, FEM at each end = WL/8 (hogging). The midspan BM under the load = WL/8 (sagging), equal to the fixed-end moments.
- 18Kinematic IndeterminacyMEDIUM
The kinematic (degree of freedom) indeterminacy of a fixed-fixed beam (ignoring axial deformation) is:
A0B1C2D3Answer: A. 0
Explanation: A fixed-fixed beam has zero rotational and translational DOF at both ends (all movements are restrained). Hence kinematic indeterminacy = 0.
- 19Shape FactorMEDIUM
The shape factor for a solid rectangular cross-section is:
A1.0B1.5C1.7D2.0Answer: B. 1.5
Explanation: Shape factor = Z_p/Z_e = (bd²/4)/(bd²/6) = 6/4 = 1.5. The plastic section modulus Z_p = bd²/4 and elastic section modulus Z_e = bd²/6.
- 20Carry-over FactorMEDIUM
In moment distribution method, the carry-over factor for a prismatic member with far end FIXED is:
A0B1/4C1/2D1Answer: C. 1/2
Explanation: When a moment M is applied at the near end of a fixed-far-end member, a moment M/2 is induced at the far end. Carry-over factor = 1/2.
- 21IndeterminacyMEDIUM
The degree of static indeterminacy of a propped cantilever is:
A0B1C2D3Answer: B. 1
Explanation: DSI = reactions - equilibrium equations = 4 - 3 = 1 (3 reactions at fixed end + 1 at prop; 3 equations of equilibrium).
- 22GeneralMEDIUM
For a determinate structure, lack of fit or temperature change generally produces
Aonly shear stressBno stress if free movement is possibleCstress always equal to yield stressDinfinite stressAnswer: B. no stress if free movement is possible
Explanation: A determinate structure can deform without restraint-induced internal forces.
- 23GeneralMEDIUM
For a beam of uniform flexural rigidity, curvature is proportional to
Ashear force onlyBbending momentCspan length squared onlyDaxial force onlyAnswer: B. bending moment
Explanation: For a beam with uniform flexural rigidity EI, the curvature κ = M/EI, where M is bending moment and EI is flexural rigidity. Curvature is directly proportional to bending moment (higher M → greater curvature). This is the basis of the Euler-Bernoulli beam theory used in structural analysis.
- 24GeneralMEDIUM
In moment distribution method, carry-over factor for a prismatic member with far end fixed is
A0B1/2C1D1/4Answer: B. 1/2
Explanation: Half the applied end moment is carried over to the fixed far end.
- 25Theory of Structures and DesignHARD
A fixed-ended beam of degree of static indeterminacy 2 requires how many plastic hinges to form a collapse mechanism under monotonic loading?
A4B1C3D2Answer: C. 3
Explanation: A structure becomes a mechanism when r + 1 plastic hinges form; for a fixed beam, r = 2, so 3 plastic hinges are required.
- 26Mechanics, Strength of Materials and Structural AnalysisEASY
Flexural rigidity is represented by:
AEABEICkADGJAnswer: B. EI
Explanation: Flexural rigidity is the product of modulus of elasticity and second moment of area.
- 27Mechanics, Strength of Materials and Structural AnalysisMEDIUM
A plastic hinge forms when a section reaches fully plastic moment capacity.
Ainitial elastic curvatureBzero stress at sectionCfully plastic moment at sectionDmaximum shear at neutral axis onlyAnswer: C. fully plastic moment at section
Explanation: A plastic hinge can rotate at approximately constant plastic moment.
- 28Mechanics, Strength of Materials and Structural AnalysisHARD
Thermal stress case: A fully restrained bar has E=1.0e+05 MPa, alpha=1.8e-05/°C and temperature rise 25°C. Thermal stress is:
A22.5 MPaB90 MPaC45 MPaD0.00045 MPaAnswer: C. 45 MPa
Explanation: For full restraint, thermal stress = E alpha DeltaT.
- 29Mechanics, Strength of Materials and Structural AnalysisMEDIUM
The proper association of section modulus is:
AEI divided by lengthBshear force divided by areaCmoment of inertia divided by extreme fibre distanceDarea divided by lengthAnswer: C. moment of inertia divided by extreme fibre distance
Explanation: moment of inertia divided by extreme fibre distance is the correct association for section modulus.
- 30Mechanics, Strength of Materials and Structural AnalysisMEDIUM
Carry-over concept: If a moment M is applied at one end of a prismatic member and the far end is fixed, carry-over moment is:
AM at far endBM/2 at far endC2M at far endDzero at far endAnswer: B. M/2 at far end
Explanation: Carry-over factor for far end fixed is 1/2.
- 31Mechanics, Strength of Materials and Structural AnalysisEASY
Rib shortening in arches usually reduces horizontal thrust.
Areduces horizontal thrustBhas no effect alwaysCincreases spanDeliminates bendingAnswer: A. reduces horizontal thrust
Explanation: Rib shortening relieves some arch thrust.
- 32Mechanics, Strength of Materials and Structural AnalysisEASY
The kern of a section is associated with:
Ano tension condition under eccentric compressionBrailway alignmentCwater treatmentDmaximum shear onlyAnswer: A. no tension condition under eccentric compression
Explanation: If load lies within kern, stress remains compressive over the section.
- 33Mechanics, Strength of Materials and Structural AnalysisHARD
fixed end moment for UDL w over fixed beam span L: choose the correct option.
AwL²/8 at midspan onlyBwL³/48EICwL/2DwL²/12 at each end with opposite signsAnswer: D. wL²/12 at each end with opposite signs
Explanation: wL²/12 at each end with opposite signs is the correct association for fixed end moment for UDL w over fixed beam span L.
- 34Mechanics, Strength of Materials and Structural AnalysisMEDIUM
Which answer correctly defines principle of transmissibility?
Aforce magnitude doublesBmoment always becomes zeroCforce can be moved along its line of action without changing external effectDforce can be moved to any lineAnswer: C. force can be moved along its line of action without changing external effect
Explanation: force can be moved along its line of action without changing external effect is the correct association for principle of transmissibility.
- 35Strength of Materials and Structural AnalysisMEDIUM
Conjugate beam method is used to determine:
ASlopes and deflectionsBCement strengthCFlow velocityDSoil compactionAnswer: A. Slopes and deflections
Explanation: In conjugate beam method, M/EI diagram is treated as loading.
- 36Strength of Materials and Structural AnalysisHARD
Fixed-end moment of a fixed beam carrying UDL w over full span L at each end has magnitude:
AwL^2/8BwL/2CwL^3/48EIDwL^2/12Answer: D. wL^2/12
Explanation: Full-span UDL on fixed beam creates hogging fixed-end moments of wL^2/12.
- 37Strength of Materials and Structural AnalysisMEDIUM
Distribution factor at a joint equals member stiffness divided by:
ACarry-over factorBLoad intensityCSpan length onlyDSum of stiffnesses meeting at jointAnswer: D. Sum of stiffnesses meeting at joint
Explanation: Moment distribution allocates unbalanced moments in proportion to stiffness.
- 38Strength of Materials and Structural AnalysisMEDIUM
Fixed end moment for a fixed beam carrying central point load W is:
AWL/16 at supports onlyBWL/8 at both ends in hoggingCWL/4 sagging at midspanDwL squared/12Answer: B. WL/8 at both ends in hogging
Explanation: A central point load on fixed-ended beam creates equal hogging fixed end moments WL/8.
- 39Structural AnalysisMEDIUM
The cable carrying a load of w kN/m of horizontal span is stretched between supports L m apart at same level and central dip h m. The maximum tension in cable is
AwL^2/(8h) sqrt(1+(h/L)^2)BwL^2/(2) sqrt(1+(L/2h)^2)CwL^2/(8h) sqrt(1+(4h/L)^2)DwL^2/(2) sqrt(1+(L/4h)^2)Answer: C. wL^2/(8h) sqrt(1+(4h/L)^2)
Explanation: H = wL^2/(8h), vertical reaction = wL/2; Tmax = sqrt(H^2+V^2) = H sqrt(1+(4h/L)^2)
- 40Structural AnalysisMEDIUM
A load W is moving from left to right support on a simply supported beam of span L. The maximum bending moment at 0.4L from the left support is:
A0.16 WLB0.20 WLC0.24 WLD0.25 WLAnswer: C. 0.24 WL
Explanation: Influence-line ordinate for BM at a section a is a(L-a)/L. For a = 0.4L, ordinate = 0.24L
- 41Structural AnalysisMEDIUM
At the location of a plastic hinge in the plastic analysis of a structure,
Aradius of curvature is infiniteBcurvature is infiniteCmoment is infiniteDflexural stress is infiniteAnswer: B. curvature is infinite
Explanation: A plastic hinge rotates at constant moment Mp while curvature becomes very large (theoretically infinite).
- 42Structural AnalysisMEDIUM
The maximum dose of plasticiser and superplasticiser for concrete, in general, is restricted to
A0.5 and 1.0 respectivelyB1.0 and 1.5 respectivelyC0.5 and 2.0 respectivelyD1.0 and 2.0 respectivelyAnswer: D. 1.0 and 2.0 respectively
Explanation: General upper limits ≈ 1.0% (plasticiser) and 2.0% (superplasticiser) by weight of cement.
- 43Original practiceMEDIUM
Loss due to elastic shortening occurs mainly in
ATimber beamsBUnreinforced masonryCRoad pavements onlyDPre-tensioned membersAnswer: D. Pre-tensioned members
Explanation: When concrete shortens elastically, bonded prestressing steel also shortens causing prestress loss.
- 44Original practiceMEDIUM
A bar carries an axial load of 120 kN over a cross-sectional area of 1000 mm². The direct stress is
A60 N/mm²B180 N/mm²C240 N/mm²D120 N/mm²Answer: D. 120 N/mm²
Explanation: Average direct (axial) stress sigma = P/A, where P = axial force and A = cross-sectional area. Assumes the load acts through the centroid and stress is uniform across the section (valid far from the load application point, per Saint-Venant's principle). Units: N/mm^2 (MPa). Stress = P/A = 120000/1000 = 120 N/mm².
- 45Cable ShapeHARD
For cable carrying a uniformly distributed load over horizontal span, which of the following rules or methods is correct?
Athe cable takes a circular profileBbending stiffness controls the profileCsag is zero at midspanDthe cable takes a parabolic profileAnswer: D. the cable takes a parabolic profile
Explanation: A cable under UDL per horizontal length forms a parabola. Correct option: D.
- 46Truss AnalysisMEDIUM
In practical design discussion of Truss Analysis, which statement best matches method of joints? Avoid the common trap that support reactions are unnecessary.
Aall zero-force members must be removed before analysisBmembers are designed for bending firstCjoint equilibrium is written with member forces as axial forcesDsupport reactions are unnecessaryAnswer: C. joint equilibrium is written with member forces as axial forces
Explanation: Pin-jointed trusses are analysed by axial equilibrium at joints. Correct option: C.