GPSC Civil Engineering (Combine Exam) Paper Solution (03-05-26) – Page 6

51) As per IS 800:2007, the design compressive strength (Pd) of an axially loaded column is calculated using the Perry-Robertson formula embedded in buckling curves. Consider the following statements:

1. The imperfection factor a depends on the buckling curve (a, b, c, d) assigned to the cross-section.
2. For a hot-rolled I-section (h/b > 1.2) with tf ≤ 40 mm, buckling about the minor axis uses curve ‘c’.
3. The non-dimensionless slenderness λ = (fy / fcc)^0.5 where fcc = π²E/(KL/r)².
4. The value of χ (stress reduction factor) is always < 1.0 for any real column.

Which of the above statements are correct?

1. 1 and 3 only
2. 1, 2 and 4 only
3. 1, 3 and 4 only
4. 1, 2, 3 and 4

52) A High-Strength Friction Grip (HSFG) bolt M20 Grade 8.8 is used in a slip-critical connection (serviceability limit). Consider the following statements:

1. The design slip resistance of a single bolt Vdsf = μr x Kh x Fo / γmf , where Fo = minimum bolt pretension.
2. For standard clearance holes, Kh = 1.0; for oversized holes, Kh = 0.85.
3. The proof load for M20 Grade 8.8 bolt is approximately 100 kN as per IS 3757.
4. HSFG bolts in bearing-type connections use the same design shear capacity as ordinary black bolts.

Which of the above statements is/are INCORRECT?

1. 4 only
2. 2 and 3 only
3. 3 and 4 only
4. 1 and 4 only

53) In plastic analysis of steel structures, which of the following statements are made?

1. The lower bound theorem states that a stress distribution that satisfies equilibrium and does not violate yield anywhere gives a load ≤ collapse load.
2. The upper bound theorem states that work done by external loads at collapse equals internal plastic dissipation for any kinematically admissible mechanism.
3. The shape factor for a solid circular section is 16/(3π) ≈ 1.70.
4. Plastic hinges in a fixed beam under central point load form first at the fixed ends before the midspan hinge forms.

Which of the above statements are correct?

1. 1 and 2 only
2. 1, 2 and 4 only
3. 2, 3 and 4 only
4. 1, 2, 3 and 4

54) Which of the following statements about ‘Gusseted Base Plates’ for steel columns as per IS 800:2007 and IS 456:2000 is incorrect?

1. The bearing pressure on the concrete pedestal must not exceed 0.45 fck (IS 456).
2. The thickness of base plate is designed as a cantilever bending under non-uniform bearing pressure and is governed by tp = √(2.5w x a²/fy) x γmo.
3. Gusset plates and stiffeners are provided to reduce the cantilever projection of the base plate.
4. The holding-down (anchor) bolts are designed for uplift and horizontal shear simultaneously.

55) In the analysis of an industrial portal frame using the plastic collapse method, the possible failure mechanisms are:

1. Beam mechanism – plastic hinges at midspan and both column bases
2. Sway mechanism – plastic hinges at column bases and beam-column junctions
3. Combined mechanism – formed by superposition of beam and sway mechanisms
4. The true collapse load is the lowest load found among all possible mechanisms (upper bound theorem)

Which combination of above statements are correct?

1. 1 and 4 only
2. 2, 3 and 4 only
3. 3 and 4 only
4. 1, 2, 3 and 4

56) For the design of a crane runway girder in an industrial building as per IS 800:2007 and IS 807, which of the following statements are correct?

1. A fatigue check is mandatory for crane girders in class of service involving more than 500000 cycles.
2. Biaxial bending check is required due to transverse (horizontal) surge force on the crane girder top flange.
3. Deflection limit for crane girders carrying Electric Overhead Travelling (EOT) cranes is typically around L/1000 or based on crane manufacturer requirements.
4. An additional surge allowance of 10% of sum of weights of crab and lifted load acts horizontally.

Which of the above statements are correct?

1. 1, 2, 3 and 4
2. 2 and 4 only
3. 1, 2 and 4 only
4. 2, 3 and 4 only

57) Which of the following statements about ‘Purlin Design’ in industrial steel roof structures is incorrect?

1. Purlins are designed for biaxial bending with load components along both principal axes.
2. Sag rods reduce the effective span for bending about the weak axis of the purlin.
3. As per IS 800:2007, for cold-formed Z-purlins used in sheeted roofs, the compression flange may receive lateral support from sheeting, increasing the design moment capacity.
4. The self-weight of the purlin and cladding both acts horizontally, but only the component perpendicular to the roof surface causes bending about the major axis.

58) For the design of a two-way restrained slab as per IS 456:2000 Cl. 24.4 and Table 26, which of the following statements is incorrect?

1. The moment coefficients αx and αy, given in Table 26 are applied to the total load per unit area x shorter span².
2. Torsion reinforcement at ‘discontinuous’ corners must be provided equal to 3/4 of the maximum midspan reinforcement, for a distance of 1/5 of shorter span in each direction.
3. At ‘continuous’ edges, torsion reinforcement is required.
4. Load dispersion from two-way slab to beams follows trapezoidal (long direction) and triangular (short direction) distributions.

59) In the design of a short column with helical reinforcement (spiral column) as per IS 456:2000, which of the following statements is incorrect?

1. 5% higher load-carrying capacity is permitted over tied columns with equal gross area and equivalent longitudinal steel.
2. The volumetric ratio of helical reinforcement ρs must satisfy: ρs ≥ 0.36 x (Ag / Ac – 1) x (fck / fy)
3. The pitch of helical reinforcement shall not exceed 75 mm or 1/6 of core diameter, whichever is less.
4. The minimum number of longitudinal bars in a spiral column is 4.

60) Which of the following statements regarding punching shear design of a flat slab column junction as per IS 456:2000 (Cl. 31.6) is incorrect?

1. If the slab punching shear capacity is inadequate, shear heads (Steel I-sections embedded in slab) are the only remedial measure permitted by IS 456.
2. The nominal shear stress τv = Vu / (bo x d), where bo is the perimeter at d/2 from column face.
3. The permissible shear stress ks x τc for punching = ks x 0.25√fck, where ks = 0.5 + βc ≤ 1.0 and βc = ratio of short to long dimension of column.
4. The critical perimeter for punching shear is taken at d/2 from the face of the column/drop panel.