ETC ETC Structural Analysis & Load Calculations 1 — Questions and Answers
Question 1: In structural engineering, what is dead load?
- The permanent, static weight of the structure and fixed components (Correct answer)
- The weight of occupants, furniture, and movable equipment
- Wind-induced forces on the structure
- Seismic inertia forces during an earthquake
Correct answer: The permanent, static weight of the structure and fixed components
Dead load is the constant gravity load from the structure's own weight and permanently attached elements such as roofing, flooring, and fixed mechanical equipment.
Question 2: What does live load represent in structural design?
- Variable loads from occupancy, furniture, and equipment that can change over time (Correct answer)
- The weight of structural framing and decking
- Forces applied during construction
- Long-term settlement loads
Correct answer: Variable loads from occupancy, furniture, and equipment that can change over time
Live loads account for the variable forces from building use, including people, furnishings, vehicles, and equipment, as specified in ASCE 7.
Question 3: What is the standard unit of stress in US customary structural engineering calculations?
- Pounds per square inch (psi) or kips per square inch (ksi) (Correct answer)
- Pounds per linear foot (plf)
- Kilonewtons per meter (kN/m)
- Pounds-force (lbf)
Correct answer: Pounds per square inch (psi) or kips per square inch (ksi)
Stress in US customary engineering is expressed in psi for low-strength materials and ksi (kips per square inch) for steel.
Question 4: What is the purpose of a factor of safety in structural design?
- To account for uncertainties in loads, material properties, and workmanship (Correct answer)
- To increase the design load to the maximum possible value
- To define the exact failure load of a member
- To eliminate the need for quality control inspection
Correct answer: To account for uncertainties in loads, material properties, and workmanship
A factor of safety multiplies the applied load or divides the material strength to ensure a structure can handle unexpected overloads and material variability.
Question 5: In beam design, what is bending moment?
- The internal force that causes a beam to bend, equal to the sum of moments about a cross section (Correct answer)
- The horizontal shear force at a support reaction
- The deflection of the beam under load
- The torsional force twisting a member about its long axis
Correct answer: The internal force that causes a beam to bend, equal to the sum of moments about a cross section
Bending moment at any cross section of a beam is the algebraic sum of all moments caused by forces acting on one side of that section.
Question 6: Which ASCE standard provides minimum design loads for buildings and other structures in the US?
- ASCE 7 (Correct answer)
- ASCE 37
- AISC 360
- ACI 318
Correct answer: ASCE 7
ASCE 7 (Minimum Design Loads and Associated Criteria for Buildings and Other Structures) is the primary US reference for dead, live, wind, snow, and seismic loads.
ETC ETC Structural Analysis & Load Calculations 1
In structural engineering, what is dead load?