Building Engineering Building Civil Engineering 4 — Questions and Answers
Question 1: What is the primary difference between a 'one-way slab' and a 'two-way slab'?
- Material used for reinforcement
- Direction(s) in which bending moments are developed (Correct answer)
- Whether the slab is prestressed or not
- Thickness relative to span
Correct answer: Direction(s) in which bending moments are developed
A one-way slab bends in a single direction, while a two-way slab bends in both directions when supported on all four sides.
Question 2: Which phenomenon causes long-term deflection in concrete structures beyond initial elastic deflection?
- Fatigue
- Creep and shrinkage (Correct answer)
- Thermal gradient
- Elastic rebound
Correct answer: Creep and shrinkage
Creep (deformation under sustained load) and shrinkage (volume reduction as concrete dries) both contribute to long-term deflection.
Question 3: What is the purpose of a 'weep hole' in a masonry retaining wall?
- Improve thermal performance
- Relieve hydrostatic pressure behind the wall (Correct answer)
- Allow inspection of wall thickness
- Anchor the wall to the footing
Correct answer: Relieve hydrostatic pressure behind the wall
Weep holes allow water to drain from behind the retaining wall, preventing buildup of hydrostatic pressure that could cause failure.
Question 4: In steel construction, what is the 'effective length factor' (K) used to determine?
- Net section area at bolt holes
- Column buckling capacity based on end conditions (Correct answer)
- Beam deflection under service loads
- Connection slip resistance
Correct answer: Column buckling capacity based on end conditions
The effective length factor K accounts for end restraint conditions to determine the effective buckling length of a column.
Question 5: What does 'liquefaction' refer to in geotechnical engineering?
- Soil consolidation under long-term loading
- Saturated loose sand behaving like a liquid during earthquake shaking (Correct answer)
- Ground water rising above the water table
- Clay losing strength due to desiccation cracking
Correct answer: Saturated loose sand behaving like a liquid during earthquake shaking
Liquefaction occurs when saturated loose granular soil loses shear strength due to earthquake-induced pore pressure increase, causing it to behave like a liquid.
Question 6: Which beam condition results in the largest mid-span deflection for the same span and total load?
- Fixed-fixed beam
- Fixed-pinned beam
- Simply supported beam (Correct answer)
- Continuous two-span beam
Correct answer: Simply supported beam
A simply supported beam has no end moment restraint, producing the greatest mid-span deflection compared to fixed or continuous conditions.
Question 7: What is the main advantage of using a mat (raft) foundation?
- It is the least expensive foundation type
- It reduces differential settlement by distributing loads over the entire building footprint (Correct answer)
- It works only in cohesive soils
- It eliminates the need for a waterproofing membrane
Correct answer: It reduces differential settlement by distributing loads over the entire building footprint
A mat foundation spreads building loads over a large area, reducing bearing pressure and minimizing differential settlement between columns.
Building Engineering Building Civil Engineering 4
What is the primary difference between a 'one-way slab' and a 'two-way slab'?