SCE Civil Engineering Fundamentals 1 — Questions and Answers
Question 1: What is the standard concrete compressive strength test specimen used in Saudi Arabia?
- 150mm cube specimen tested at 28 days (Correct answer)
- 6×12 inch cylinder
- 4×8 inch cylinder
- 100mm cube specimen
Correct answer: 150mm cube specimen tested at 28 days
Saudi Arabia follows the British Standard practice of using 150mm cube specimens for compressive strength testing at 28 days, unlike the US practice of using 6×12 inch cylinders.
Question 2: In reinforced concrete design, the purpose of minimum reinforcement is to:
- Prevent sudden brittle failure when the concrete cracks (Correct answer)
- Reduce cost
- Increase workability
- Improve aesthetics
Correct answer: Prevent sudden brittle failure when the concrete cracks
Minimum reinforcement ensures that when the concrete section cracks, the steel can carry the tensile force without sudden failure. This provides ductile behavior and warning before failure.
Question 3: The California Bearing Ratio (CBR) test is used to evaluate:
- The strength of subgrade and base course materials for pavement design (Correct answer)
- Concrete compressive strength
- Steel tensile strength
- Soil permeability
Correct answer: The strength of subgrade and base course materials for pavement design
The CBR test measures the resistance of a soil or aggregate to penetration, expressed as a percentage of a standard crushed stone. It is the primary input for flexible pavement thickness design.
Question 4: What is the water-cement ratio's effect on concrete strength?
- Lower w/c ratio generally produces higher strength concrete (Correct answer)
- Higher w/c ratio produces higher strength
- w/c ratio has no effect on strength
- Only affects workability, not strength
Correct answer: Lower w/c ratio generally produces higher strength concrete
Abrams' law states that concrete strength is inversely proportional to the water-cement ratio. Lower w/c ratios produce denser, stronger concrete but reduce workability.
Question 5: The maximum allowable settlement for most structures in Saudi Arabia's sandy soils is typically:
- 25mm total settlement (Correct answer)
- 100mm total settlement
- 5mm total settlement
- 50mm total settlement
Correct answer: 25mm total settlement
Most building codes limit total settlement to about 25mm and differential settlement to about 20mm for conventional structures. Saudi sandy soils can have rapid settlement under loading.
Question 6: What type of foundation is most commonly used for high-rise buildings in Jeddah's weak soil conditions?
- Bored piles (drilled shafts) bearing on rock (Correct answer)
- Isolated footings
- Strip foundations
- Raft foundations alone
Correct answer: Bored piles (drilled shafts) bearing on rock
Jeddah's coastal soils are often weak and compressible, requiring deep bored piles that transfer loads through weak layers to competent rock or dense soil at depth.
SCE Civil Engineering Fundamentals 1
What is the standard concrete compressive strength test specimen used in Saudi Arabia?