Civil Engineering Fundamentals Flashcards

What is the standard concrete compressive strength test specimen used in Saudi Arabia?

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.

In reinforced concrete design, the purpose of minimum reinforcement is to:

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.

The California Bearing Ratio (CBR) test is used to evaluate:

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.

What is the water-cement ratio's effect on concrete strength?

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.

The maximum allowable settlement for most structures in Saudi Arabia's sandy soils is typically:

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.

What type of foundation is most commonly used for high-rise buildings in Jeddah's weak soil conditions?

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.