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- Sample report of
a column base investigation
COLUMN BASE INVESTIGATION
I. Purpose of Investigation:
At the request of contractor, Thomas R.
Price P.E., of Structural Solutions LLC
the facility for the purpose of viewing
column base distress in various steel
II. Description of Buildings:
The buildings in question are metal
buildings manufactured by an MBMA
the purpose of this report, Building 12
will be used as a representative example
various buildings in question.
The example building is a 108' wide by
422" long x 14" eave, clearspan
gable building with
3:12 roof slope. (ref. Fig. A).
Buildings were fabricated and erected in
Concrete spalling at column bases and
lateral shifting of the columns at their
observed by owner following snow build up
on roof last winter.
IV. Referenced Documents:
MBMA manufacturer drawings.
Pier Schedule and Footing Detail.
Architect notes and sketches.
V. Field Observations and Notes:
The inspection took place between 10:00
pm and 1:00 pm. Our comments relative to
inspection of the column bases are listed
1) Building sidewall column bases were
observed to have translated laterally in
plane of the frame by as much as 3
inches. The (2) 1-1/4" dia. anchor
been broken free of their bond to the
concrete. The concrete between the anchor
bolts and the edge of concrete was
spalling off. Steel angle members were
welded to the column bases, hooking over
the inside edge of the pier, in order to
restrain further movement. Many columns
were observed to be in this condition.
Column base forces as provided by MBMA
manufacturer drawings were used
for calculations involving the
foundations in question.
Calculations show that, absent any
reinforcement restraining the anchor
against lateral bursting, an edge
distance of 15" is required. If
were utilized to restrain lateral shear,
a minimun edge distance of 5-1/2" is
The calculated lateral strength of the
as-built, 4" edge distance without
steel, is 9680 lb. The required strength
is 39,600 lb. (Ultimate strength,
loads) In our judgement it is this
shortcoming that caused the anchorage
The hairpins ties to the floor may be
considered to provide resistance to
of the footing. However, this resistance
is limited to the floor area attributable
column, and calculation shows this to be
approximately 4500 lb. This is well short
the required 23,300 lb. (Service load).
Review of the 4'-0" x 4'-0"
footings, considered as 5'-0" x
4'-0" x4'-0" deep, and
absent any hairpin restraint for purpose
of calculation, shows excessive soil
(>10,000psf) and inadequate factor of
safety against overturning. The weight of
footings plus grade wall and floor slab
portions attributable to uplift
somewhat short of the required uplift
resistance indicated by the
Therefore, had the column piers held the
load, or, if they are repaired in some
so as to hold the load, the effectively
non-restrained footings would be
A solution which addresses both the
anchor bolt lateral bursting problem, and
footing overload problem is necessary.
The repair detail by the architect does
not adequately address all of the design
issues, in our judgement.
Existing piers must be cut out and
re-poured per a new design. Anchor bolts
must be re-
placed in this pour. This is likely to be
necessary in any proposed repair. Wind
require uplift resistance of 18,000 lb,
which is clearly not available with the
in their current loosened condition. It
should be noted that this lack of uplift
represents an existing danger of building
failure under wind loading.
The following pages outline three
recommendations for remedying the
problems. These recommendations are
preliminary and not for construction.
details of any agreed upon repair
procedure are necessary prior to
beginning work in
- 1200 Troon
- Grand Rapids, MI
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2012 Structural Solutions LLC, 1200 Troon Ct. SE
Grand Rapids, MI 49546 Kent County