Calculate the seismic design category for a building in Hawaii with a mapped spectral acceleration (Ss) of 0.75g and site class D soil conditions.
Correct Answer
B) Category D
With Ss = 0.75g and site class D conditions, the adjusted spectral acceleration places the building in Seismic Design Category D, requiring enhanced seismic detailing.
Why This Is the Correct Answer
With Ss = 0.75g and site class D, the site coefficient Fa amplifies the short-period acceleration. Applying ASCE 7 / IBC methodology, the adjusted SDS value with site class D amplification places this building in Seismic Design Category D. SDC D triggers enhanced seismic detailing requirements, special inspections, and restrictions on certain structural systems.
Why the Other Options Are Wrong
Option A: Category B
Category B applies to buildings with very low seismic demand (low SDS and SD1 values). With Ss = 0.75g and the amplifying effect of site class D soil, the demand is far too high for Category B classification.
Option C: Category E
Category E applies to Risk Category IV essential facilities (hospitals, emergency response) or to buildings with very high seismic demand (SDS ≥ 1.25g). The building described does not meet either threshold.
Option D: Category C
Category C applies to moderate seismic demand levels. While Ss = 0.75g alone might suggest borderline conditions, the site class D amplification pushes the adjusted spectral acceleration into Category D territory.
Memory Technique
SDC determination: Start with Ss → apply Fa for your site class → calculate SDS → look up SDC table. Site class D is a 'danger amplifier' — soft soil makes earthquakes worse. 'D soil, D category' is a useful (though not universal) memory hook for this problem.
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
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?
Next Question
A foundation system requires 12 concrete piers, each 18 inches diameter and 8 feet deep, in volcanic soil. Calculate the total concrete volume needed in cubic yards.