HomeMy WebLinkAboutPermit Correspondence 2005-7-22
Frorn:GEOM~'x. INC.
541 942 7935
07/22/2005 08:10 #001 P.001/002
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July 22,2005
PROFESSIONAL ENGINEERS
LAND SURVEYORS
BUILDING DESIGNERS
806 N NINTH STREET COTTAGE GROVE, OREGON 97424
TELEPHONE (541) 94]'()12G FAX (541) 942,7935
Ann Bowers
Tony Casada
45825 Goodpasture Road
Vida, OR 97488
VIAfax: 541-896-3968
RE: Foundation Stabilization, 825 S. 73rd St , Springfield, OR
Dear Ann and Tony:
On July 18, 2005 I observed pier load tests performed by Ram-Jack of Oregon, LLC
I noted that Ram.Jack of Oregon had installed 6 each 2-7/8" diameter ('push piers" and model
400.5 foundation brackets, all manufactured by Ram-Jack, at the approximate locations noted on
our plans for helical pier installation. The piers were generally placed slightly closer together than
the maximum spacing called for on our design. resulting in less pier load and less moment on the
footing/foundation system, except at the garage door where spacing was dictated by door width.
According to Ram-Jack manufacturer data provided by Ken Marquardt (Ram-Jack of Oregon,
LLC), the piers themselves have a safe working compression load of 25,000 pounds each. This
exceeds the expected ,~ctual maximum load of some 16,000 pounds (based on 8' spacing).
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A pressure of 42,000 pounds was applied to each of the three northern piers on the side of the
home, 30,500 pounds to the pier on the outside corner of the garage and 36,500 pounds to each
pier on the sides of the northern garage door These pressures were applied with no apparent
settling of the piers. Therefore the piers appear to be capable ofwithstandmg the design loads
without settlement.
The design ofthe foundanon stabilization measures, including location and loading, was based on
measurements of soil load resistance determined from dynamic penetration testing of the soils in
the area where settlement of the foundation was noted as authorized by the client in the agreed on
scope of service
We note that these types of foundation stabilization repairs are not unconditionally guaranteed to
halt all settlement, however, minor settlements (pier creep) can be removed by fe-leveling the
piers as needed (typically after 3 to 5 years). In more extreme cases, the entire hillside may be
mobilized pushing both home and piers downslope, '
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From:GEOMAX. INC.
541 842 7835
07/22/2005 08:10 ~J01 P.002/002
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Ann Bowers and Tony Casada
Foundation Stabilization at 825 S 73rd St. Springfield, OR
July 22, 2005
Although we have seen no overt evidence that the hillside is unstable, slope instabthty IS always a
risk with homes built on steep hillsides Assessment of the degree of hillside stability requires a
slope stability analysis based on shear tests of undisturbed soil samples from the hill and sufficient
test holes to estabhsh depth to bedrock or lack thereof at or above potential failure surfaces This
level of effort was beyond that authorized by the Client and no general slope stability analysis has
been performed.
A secondary risk involved with foundation stabilization has been alluded to above and consists of
the possibility of the piers slowly settling into the soil. This phenomenon will occur, if at all, over
a period of years and is generally easily corrected by re-Ieveling the foundation by the adjustable
pier brackets The use of a safety factor in the load test of 2.5 should minimize any future re-
leveling requirement.
Finally, we had recommended earlier that the post in the garage be shimmed to help re-Ievel the
floor above. No pier was recommended for placement under the post foundation due to the
difficulty in accessing the post footing below the concrete garage slab and the relatively minor
settling apparent at the post location It is our opinion, based on our initial level survey of the
home and our experience in this area, that shimmmg the post would allow the floor to be leveled.
In addition, the load on the post footing is lessened after the foundation stabilization and further
settlement should not be a problem at the post foundation. However, this post may require
additional shimming in the future to maintain the main floor elevation above
Due to the inherent uncertainties associated with the limited investigation performed for this
work, the author offers no warranties, either express or implied, regarding the general stability of
the hillside
If you have any questions regarding the stabilization of the foundation of this home, please call me
at your convenience. Thank you for choosing Geomax, Inc. for your engineering needs
Yours truly,
Geomax, Inc.
~~~
Ronald D. Rice, P.E.
Senior Principal
cc Ken Marquardt, Ram-Jack of Oregon, LLC 688-4991
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