ETC ETC Structural Analysis & Load Calculations 2 — Questions and Answers
Question 1: What is the difference between a simply supported beam and a cantilever beam?
- A simply supported beam rests on two supports; a cantilever is fixed at one end and free at the other (Correct answer)
- A simply supported beam spans three supports; a cantilever spans two
- Simply supported beams carry only axial load; cantilevers carry only shear
- They are identical in behavior but differ in cross-section shape
Correct answer: A simply supported beam rests on two supports; a cantilever is fixed at one end and free at the other
A simply supported beam has pinned or roller supports at each end allowing rotation; a cantilever has a fixed support at one end and extends freely at the other.
Question 2: What does shear force cause in a structural member?
- Sliding failure along a cross section perpendicular to the member axis (Correct answer)
- Buckling of a slender compression member
- Tensile cracking along the member's neutral axis
- Rotation of the member about its longitudinal axis
Correct answer: Sliding failure along a cross section perpendicular to the member axis
Shear force acts transversely to a structural member, tending to cause adjacent sections to slide past each other, and governs design of web thickness in beams.
Question 3: What does tributary area mean in structural load distribution?
- The floor or roof area that contributes load to a specific structural member (Correct answer)
- The watershed area draining to a stormwater inlet
- The total area of a floor plate divided by the number of columns
- The zone of influence around a deep foundation
Correct answer: The floor or roof area that contributes load to a specific structural member
Tributary area is the portion of floor, roof, or wall area that is supported by and loads a particular beam, column, or foundation element.
Question 4: In column design, what is Euler buckling?
- The axial compressive load at which a slender column buckles laterally (Correct answer)
- The load that causes direct compression failure in a short column
- The tension force that yields a steel column
- The eccentric load producing combined bending and compression
Correct answer: The axial compressive load at which a slender column buckles laterally
Euler's critical buckling load defines the theoretical axial load at which an ideal slender column loses stability and buckles laterally.
Question 5: What is the modulus of elasticity for structural steel in US practice?
- 29,000 ksi (29 million psi) (Correct answer)
- 3,000 ksi
- 57,000 times the square root of f prime c psi
- 10,000 ksi
Correct answer: 29,000 ksi (29 million psi)
The modulus of elasticity for structural steel is 29,000 ksi (29 x 10 to the sixth psi), a constant used to calculate deflections and buckling loads.
Question 6: What does load path describe in structural engineering?
- The route by which forces travel from their point of application through the structure to the foundation (Correct answer)
- The schedule for delivering structural materials to the site
- The sequence of construction for load-bearing members
- The distribution of wind loads across a building facade
Correct answer: The route by which forces travel from their point of application through the structure to the foundation
Load path traces how gravity, wind, and seismic forces flow from floors and roofs through beams, columns, and walls into the foundation and soil.
ETC ETC Structural Analysis & Load Calculations 2
What is the difference between a simply supported beam and a cantilever beam?