PE Civil (NCEES Principles and Practice of Engineering)

Free practice

Sample PE Civil (NCEES Principles and Practice of Engineering) questions

A few real questions from the bank, each with the correct answer and a written explanation. Every question is free — no signup to start.

1. Structural Engineering

   1. A simply supported beam of span 8 m carries a uniformly distributed load of 4 kN/m over its full length. What is the vertical reaction at each support?

   • a.16 kNCorrect
   • b.32 kN
   • c.64 kN
   • d.8 kN

   Why: The total load is w·L = 4 x 8 = 32 kN. By symmetry each support carries half: 32/2 = 16 kN, which also equals w·L/2. Symmetric loading always splits equally between the two supports.

2. Structural Engineering

   2. For that same simply supported beam (span 8 m, uniform load 4 kN/m), what is the maximum bending moment?

   • a.32 kN·mCorrect
   • b.16 kN·m
   • c.256 kN·m
   • d.64 kN·m

   Why: The maximum moment for a simply supported beam under a uniform load occurs at midspan and equals w·L^2/8 = 4 x 8^2 / 8 = 4 x 64 / 8 = 32 kN·m. The moment diagram is parabolic, peaking at the center.

3. Structural Engineering

   3. What is the moment of inertia about the centroidal axis of a rectangular cross-section 200 mm wide and 300 mm deep (bending about the strong axis)?

   • a.9.0x10^8 mm^4
   • b.2.25x10^8 mm^4
   • c.1.8x10^9 mm^4
   • d.4.5x10^8 mm^4Correct

   Why: For a rectangle, I = b·h^3/12 where h is the dimension parallel to the load. I = 200 x 300^3 / 12 = 200 x 2.7x10^7 / 12 = 4.5x10^8 mm^4. Depth is cubed, so orienting the section deep-side up sharply increases stiffness.

4. Structural Engineering

   4. What is the section modulus of a rectangular cross-section 200 mm wide and 300 mm deep about its strong axis?

   • a.9.0x10^6 mm^3
   • b.3.0x10^6 mm^3Correct
   • c.6.0x10^6 mm^3
   • d.1.5x10^6 mm^3

   Why: Section modulus S = b·h^2/6 = 200 x 300^2 / 6 = 200 x 90,000 / 6 = 3.0x10^6 mm^3. Bending stress is M/S, so a larger section modulus lowers the stress for a given moment.

5. Structural Engineering

   5. What is the specified minimum yield strength, Fy, of ASTM A36 structural steel?

   • a.60 ksi
   • b.29,000 ksi
   • c.50 ksi
   • d.36 ksiCorrect

   Why: A36 steel has a minimum yield strength of 36 ksi (about 250 MPa), the value in its designation. A992 steel is 50 ksi and Grade 60 rebar is 60 ksi; 29,000 ksi is steel's modulus of elasticity, not a strength.

6. Structural Engineering

   6. In LRFD design, which load combination correctly factors dead load (D) and live load (L) for a basic gravity case?

   • a.1.2D + 1.6LCorrect
   • b.0.9D + 1.6L
   • c.1.4D + 1.7L
   • d.1.0D + 1.0L

   Why: The governing ASCE 7 strength combination for dead plus live load is 1.2D + 1.6L. The higher factor on live load reflects its greater uncertainty. The 1.4D + 1.7L form is the older ACI ultimate-strength combination, not current LRFD.