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I. Purpose of Investigation: 2 of 3
At the request of the Contractor, Thomas
R. Price P.E., of Structural Solutions LLC, inspected the equipment repair building in
Portage MI, in the attempt to determine the structural effects of installing a re-roof system
over the existing roof, thereby increasing the gravity load that the structure must carry.
II. Description of Building:
The building is a single storey pre-engineered metal building. The main building dimen-
sions are approximately 82 ft. x 142 ft. x 20 ft. eave. There are (2) lean-to additions:
36 ft. x 33 ft. and 24 ft. x 33 ft., both to be re-roofed. A 71 ft. x 26 ft. addition at one
endwall and a higher eave addition at the opposite endwall, are not included in the
areas planned for re-roofing.
Our best information is that the main building was constructed in 1976. The facility
is currently in operation as a truck maintenance building.
Roof leak problems have created the need to repair the roof, and the re-roofing system
described below is under consideration for this purpose.
IV. Field Observations and Notes:
The structural framing of the building appeared to be in generally good condition.
Column mounted jib cranes were observed at two locations which did not appear to
have been intended in the building design. These columns should be checked for
adequacy to support the crane forces.
A line of single channel endwall posts at the rear of the building have had their girts
and wall panels removed, to accommodate a subsequent expansion. These members
are likely overstressed under full roof load, and should be braced at the original girt
V. Recommendations: 3 of 3
MBC Sec. 3402.2 allows for increases in structural member forces of up to 5 percent,
when making alterations or repairs to a structure.
The proposed re-roofing system has a self weight of 1.25 psf. If the original building
was designed for at least 25 psf gravity roof load, then the re-roofing materials can be
installed, without any structural reinforcement necessary. Therefore, verification of
original design loads is needed. Buildings in this area, and of this type, are and have been
routinely designed for 30 psf or more snow load, and 3 psf dead load, so it is likely that
the original design loads exceeded 25 psf. Verification is best made by reviewing the
original building plans, or similar documentation.
If original design documentation cannot be found, it may be possible to verify that at
least 25 psf was used in design, by performing a structural survey, analysis and design
check of a typical frame and roof purlin. Depending on the results, it may also be
necessary to perform material tests on samples of the steel.
MBC 3402.2 also calls for any structural elements which are found, in the course of
altering or repairing, to be deficient, be reinforced, or otherwise made to meet current
Code requirements. The jib crane columns and endwall columns described above,
must be addressed, in order to meet this Code provision.
- 1200 Troon
- Grand Rapids, MI
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2012 Structural Solutions LLC, 1200 Troon Ct. SE
Grand Rapids, MI 49546 Kent County