HomeMy WebLinkAboutPermit Correspondence 2007-10-16
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K & A Engineering, Inc.
P.O. Box 23624, Eugene, OR 97402
521 Market St., Suite B, Eugene, OR 97402
(541) 684-9399 Voice
(541) 684-9358 FAX
engineering
October 16, 2007
Mr. Jeff Towery
6883 Forsythia Street
,Spnngfleld, OR 97478
Project: 223.06
Subject. Special inspection - foundation repair
Spnngfleld permit no COM2007 -01346
6883 Forsythia St., Spnngfleld, OR
PURPOSE AND SCOPE
As requested, K & A Englneenng, Inc has made several Inspections of the subject foundatIOn repair project
currently underway. The purpose of our Inspections were to review work completed, provide recommendations
to the contractor for reqUired changes or modifications, and to ensure that the work completed met the
specifications and Intent of the repair plan.
This project Includes repair of the foundation of the west side of the garage only and Installation of drainage
along the west side of the residence. This repair plan does not include underpinning or repair of other parts of
the foundation
INSPECTIONS
Subsurface Drainage System
We Inspected the new subsurface drain system as It was constructed This system was installed according to
our specifications and recommendations. The trench extended below the ground surface to native undisturbed
sandstone The side of the trench facing the foundatIon extended through approximately 2-feet of saturated
organic clays located on the surface of native sandstone The trench depth ranged from 4 to over 6-feet in
depth. A significant amount of water was drained from the organic layer dunng construction.
The perforated trench drain pipe was connected to a solid drain pipe which was routed to the curb weep hole on
the south Side of the street at the west side of the driveway
West Garage Foundation
Shonng and Removal of EXlstmg Footing and Slab
The west garage wall and roof structure was shored and separated from the foundation and approximately 10.6-
feet of the west footing and stem wall was removed, extending from the west Side of the portal frame at the
garage opening to the man door. See the attached As-BUilt Repair Plan Additionally, a portion of the eXisting
intenor concrete slab-on-grade was removed.
K & A Engineering, Inc.
After removal of the slab and existing foundation, the west portal frame footing and wall were repositioned to a
plumb condition.
Helical PIer Installation
Three helical piers were installed at the locatIons shown on the attached As-Built Repair Plan. Two of the piers
support a preconstructlon liT" bracket to be embedded Into the new concrete grade beam. The thIrd pier,
located at the remaining existing portal frame foundation, supports a conventional steel bracket Due to the
location of large boulders In the bedrock, the pier locations and helix configurations were modified from the
onglnal repair plan We evaluated the static load capacity of the piers, as Installed, and have determined that the
available load capacity exceeds the reqUired capacity. See Table 1 for a summary of the pier installatIOn.
Table 1 - Helical Pier InstallatIOn Summary
Required
Allowable Minimum
Pier Description Installed Installation Load Load
and Location Depth, ft. Torque, k-ft Capacity, kips Capacity, kips
12" /14" Pier with 9.5' 6.8 170 <3.0
standard bracket at
eXIst. Footing near
NW Corner
8" / 10" Pier with 90 6.8 82 5.7
"T" bracket near
center of new grade
beam
12" Pier with "T" 9.0 66 6.9 1 1
bracket near south
end of new grade
beam
Concrete Grade Beam
A new concrete grade beam was constructed with the dimensions and reinforcing meeting our onglnal
speCifications ThiS grade beam was attached to the remaining existing portal frame foundation at the northwest
corner. The grade beam was attached to the existing foundation uSing 4 - 5/8" diameter grade 60 steel dowels
that extended a minimum of 7 -inches Into the eXisting concrete. The grade beam was reinforced according to
the project design and speCifications.
C(Jpple Wall
The eXisting framed cnpple wall supporting the floor of the residence along the south side of the garage was
repaired according to our plans
SUMMARY AND RECOMMDATIONS
ThiS report documents our Inspections made of construction for the subject project. Work completed as of the
date of thiS report Includes construction of an extenor perimeter subsurface drain system, installation of three
(3) new helical piers, cripple wall repaIr, and a new concrete grade beam The construction of these elements
Project. 223.06
Client. Towery
6883 Forsythia St , Spnngfleld, OR
Page 2 of 3
October 16, 2007
K & A Engineering, Inc.
was made In accordance with our design or, In the case of changes, was made with our approval and according
to modified design recommendations
We recommend acceptance of these elements, as constructed, by the local building official.
The project IS not yet completed, and we anticipate making at least one more inspection report based on
additional site Inspections
Thank you for the opportunity to be of service. Please call me If you have any questions.
Sincerely,
Project: 223.06
Client Towel}'
6883 Forsythia St , Spnngfleld, OR
Page 3 of 3
October 16, 2007
, k.a
engineeflng
geotechnical/civil
engineering
Eugene, OR 97408
541 684 9399 541 684 9358 fax
"
Project: 6883 Forsvthla St.
Client: Towrev
Job No: 223.06 Date: 9-28-07
Sheet. 1 of 1
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& STEEL HELICAL PIER WITH PIER BRACKET AT EXISTING FOOTING
<8 STEEL HELICAL PIER WITH "T" FITTING SUPPORTING NEW CONCRETE GRADE BEAM