What is the required concrete cover for reinforcing steel in Hawaii coastal exposure conditions according to building code?
Correct Answer
B) 2 inches
For coastal exposure conditions in Hawaii, reinforcing steel requires 2 inches of concrete cover minimum to protect against chloride penetration and corrosion.
Why This Is the Correct Answer
Option B (2 inches) is correct. For coastal exposure conditions, ACI 318 and Hawaii building codes require a minimum of 2 inches of concrete cover over reinforcing steel. This thickness provides adequate protection against chloride ion penetration from salt spray, which is the primary corrosion threat in Hawaii's marine environment.
Why the Other Options Are Wrong
Option A: 2-1/2 inches
2-1/2 inches exceeds the required minimum for standard coastal exposure. While more cover is never harmful, the code-specified minimum for coastal conditions is 2 inches, not 2-1/2 inches. This figure may be confused with cover requirements for concrete cast against and permanently exposed to earth (3 inches) or other severe exposure categories.
Option C: 3 inches
3 inches is the required cover for concrete cast against and permanently exposed to earth (e.g., footings in direct soil contact), not for coastal atmospheric exposure. Confusing these two distinct exposure categories is a common error.
Option D: 1-1/2 inches
1-1/2 inches is the minimum cover for interior conditions or protected exposure (e.g., slabs and walls not exposed to weather). Coastal Hawaii is a much harsher environment and requires greater protection than interior or mild exterior conditions.
Memory Technique
Think '2 inches for 2-sided threat' — coastal rebar faces both salt spray from the ocean AND tropical humidity, so it gets 2 inches of protection. Interior rebar (only one mild threat) gets 1-1/2 inches. Buried rebar (soil contact) gets 3 inches.
More Hawaii Questions
A concrete mix design for coastal construction specifies a water-cement ratio of 0.40. If 650 lbs of cement is used per cubic yard, how many gallons of water should be added?
A contractor is installing hurricane straps rated at 1,500 pounds each. If the calculated uplift force on a rafter is 3,200 pounds, how many straps are required with a 2.0 safety factor?
Hawaii Building Code requires special inspection for concrete placement in seismic design categories. What is the minimum frequency for concrete strength testing?
What is the maximum allowable deflection for roof rafters under design wind loads in Hawaii's hurricane zones?
Which roofing attachment method is specifically required in Hawaii's hurricane zones for asphalt shingles on residential construction?
A building in Maui requires hurricane straps rated for 175 mph winds. If each strap must resist 1,200 lbs of uplift force and you have 48 roof-to-wall connections, what is the total uplift resistance provided?
During construction of a beachfront property, you notice white crystalline deposits forming on the concrete surface. This indicates:
You discover expansive clay soil conditions during excavation for a residential foundation in Kona. The plasticity index is 28. What foundation system is most appropriate?
According to Hawaii building requirements, hurricane straps connecting roof trusses to wall plates must be rated for what minimum uplift force in high wind zones?
A concrete slab foundation in Hawaii requires a vapor barrier. Due to high humidity and frequent rainfall, what type of vapor barrier is most appropriate?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass
Project Management
60 questions · 70% to pass
Related Study Resources
Previous Question
A concrete slab in a coastal Hawaii location requires 3 inches of cover over reinforcing steel. If #4 rebar (0.5" diameter) is used, what is the minimum slab thickness?
Next Question
Under Hawaii's hurricane building standards, what is the minimum design wind speed for residential construction in Hurricane Zone 1?