ARE Live: Structures Discussion

Review the mock exam questions in preparation for the episode with Adam Coers by 12:00PM Central Time on Thursday, March 17th, 2022.

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* 1. For a new high school gymnasium in Denver, Colorado, the architectural and development team has reviewed and analyzed the geotechnical report during their initial preliminary design process. The report shows that the first 12” of the soil is organic material, from 1’ to 6’ the soil is a silty mix with a potential capacity of approximately 1,200 PSF, from 6’ to 8’ the soil is a silty sandy mix with a potential capacity of approximately 1,500 PSF, from 8’ to 55’ the soil is a gravelly sand mix with a potential capacity of approximately 5,000 PSF, and below 55’ is a rock base with a potential capacity of approximately 8,000 PSF. The blows per foot are in typical ranges, the liquid limit is 60, and the water table is shown to be at 13’ below grade.

What is the likely location for the bottom of the foundation footings?

Caissons to 56’ to get the best rock soil capacity

At 10’ below grade for solid capacity, but less expensive than caissons

At the “Frost Depth” for Denver which is 36” below grade

There is no reason to review the soils information until there is a viable approved design option, likely during the Design Development phase

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* 2. While detailing the retaining wall for the garden entrance sequence, you realize you need to add the required reinforcing.

Referencing the image below, which of the following is the most likely?

Option A

Option B

Option C

Option D

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Question 2

Question 2

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* 3. To finalize the Schematic Design for a single-story small gymnasium for the junior high school your firm is designing, you make a reasonably accurate best guess for the structural system for the 68’ clear span. Choose one.

Vierendeel trusses

Steel wide flanges

6” Flat concrete slab

Open web steel joints

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* 4. For a small 2,000 sf single story Field House project deep in a beautiful park area is under consideration. The Client, the Park District, gives the Architect the geo-tech report which clearly states that the soil capacity in the pre-determined site area below the organic material that makes up the first 18” is a comparatively poor silty-sand of approximately 1,000 psf down to about 20’ deep. It does note, however, that there is a high quality bedrock “soil” at approximately 65’ deep with a capacity of 8,000 psf.

The one story building should probably be considered in which of the following ways:

60” diameter caissons at the column points to the bedrock

Raft (or Mat) construction

Bearing wall with strip foundations

Steep angle roofs to shed snow to reduce the snow loads