HomeMy WebLinkAboutPlans (24) r "CROSSING AT BULL MOUNTAIN" �A/ L / .�ar. h. Q
LOT 21 .11 FOUNDATION CERTIFICATION
SE 1/4 SEC. 8, T 2 S, R 1 W, W.M.
CITY OF TIGARD, WASHINGTON COUNTY. OREGON
SURVEYED JUNE 29, 2023/$
�� 1 4fj4VC
PREPARED FOR:
/sW ICHIJO USA
�" 9 SW SUNSET B LVD. SUITE 2-D
p g' g7z2PaRTLAND, 97239
9. / L O T
E 22
I 6.00''
PUBLIC
a w UTILITY
in ( EASEMENT
N
k 18.45, N89`55'53"E J 90.00' ! 21.52'
LOT
20 50.63'
w w
in
' >� 21.30'}—+^ p a4--18.07 n a #i 2.ao• I 0
a
LOT aw* moo' 's
O 23.30`
o 0_
p 28.07'
vl
q O 38.63'
Y. ,
fl-
S89.55'53"W f 75.00'
3 0
E
1
REGISTERED
do PROFESSIONAL J
rn LAND SURVEYOR
c
f SW VANDERWOOD AVENUE
o-
OREGON
a JULY 9.2002
TRAMS C. JANSEN
n 57751 1 I `\, (i)
o RENEWS: 6/30/2025
m I CERTIFY THAT I HAVE VERIFIED THE LOCATION OF THE SCALE
p FOUNDATION UPON THE HEREIN DESCRIBED REAL PROPERTY 20 10 0
2 AND THAT I FOUND THE IMPROVEMENTS AS. SHOWN TO BE ,
UPON THE PREMISES AS HEREIN DESCRIBED, AND THEY DO 1 INCH = 20 FEET
g NOT ENCROACH ON THE PROPERTIES ADJACENT THERETO.
DRAWN BY; MJL DATE:06/29/23
.s. PACIFIC COMMUNITY DESIGN
. REVIEWED BY; T2 DATE:06/29/23 PLANNING ENGINEERING SURVEYING
�. PROJECT NO.: 139-001 (503) 941-9484
669 e 1 -qce av�
iS�ZGz2- CoL1V/ Ga ►RcIFIc
Real-World Geotechnical Solutions
Investigation • Design •Construction Support
June 28, 2023
Project No. 22-6162
Ichijo USA Co., LTD
Attn: Erik Gomez
1509 SW Sunset Blvd. Suite 2-D
Portland, Oregon 97239
Via email to: erik.gomez(a�ichilousa.com
FOUNDATION SUBGRADE REVIEW
LOT 21 RIVER TERRACE CROSSING AKA CROSSING AT BULL MOUNTAIN
15649 SW PEACE AVENUE
TIGARD, OREGON
This letter addresses the single-family home foundation subgrade on Lot 21 of the River Terrace
Crossing development, also known as Crossing at Bull Mountain. We understand that the proposed
building is a two-story home with a crawlspace. There is an existing Lock+Load retaining wall along
the west and south property lines. On June 13, 2023 we visited the site and observed that the
excavation was completed. The excavation along the southern edge of the house was about 2 to
2.5 feet below surrounding grades, directly behind the counterforts of the existing Lock+Load wall.
The exposed height of the Lock+Load wall along this side is only about 32 inches, so the proposed
building footing will be adequately embedded and the retaining wall will not be significantly impacted.
The excavation for lot 21 is stepped up to the north. The retaining wall on the west side of the lot
has an exposed height of approximately 3 feet or less and the footings are setback at a distance of
at least 8 feet. The exposed subgrade generally consisted of very stiff gravelly silt engineered fill
material.
The footing excavations were generally set back at a sufficient distance and at a sufficient depth to
be outside of a 1 H:1 V (Horizontal to Vertical) influence zone measured from grades at the bottom
face of the wall. Footing-to-slope and footing-to-wall setbacks appear to be adequate.
Based on observed conditions, foundation subgrades as prepared are considered suitable to
support the planned allowable bearing pressure of 1,500 psf. Estimated settlement under the
allowable bearing pressure is 1-inch total, and inch differential, measured over a horizontal
distance of 20 feet. On June 12, 2023, we observed that the crushed aggregate backfill in the lateral
trench at the front of the lot was loose to a depth of about 2 feet. We recommended that the
contractor compact that backfill. On June 20, 2023, we returned to the site and observed that the
contractor had carried out our recommendation and compacted the trench backfill to a dense,
unyielding state.
Care should be taken to avoid saturation or disturbance of footing subgrade soils during and after
excavation. If footing bearing soils become saturated or disturbed, any softened soil or slough
should be removed and replaced with crushed aggregate or additional concrete. In general, footing
14835 SW 72"d Avenue Tel(503)598-8445
Portland,Oregon 97224 Fax(503)941-9281
GeoPacific Engineering, Inc.
Job No.22-6162
Lot 21 River Terrace Crossing
excavations should be cleaned such that no more than approximately 1/2-inch of loose soils are
present prior to pouring concrete. Also, crushed rock placed over the surface of the subgrade should
be compacted so that no more than approximately 1/2-inch of loose gravel is present prior to pouring
concrete.
Construction should include typical measures for controlling subsurface water beneath the homes,
including positive crawlspace drainage to an adequate low-point drain exiting the foundation,
visqueen covering the exposed ground in the crawlspace, and crawlspace ventilation (foundation
vents). The homebuyers should be informed and educated that some slow flowing water in the
crawlspaces is considered normal and not necessarily detrimental to the home given these other
design elements incorporated into its construction. Adequate crawlspace drainage is not something
that geotechnical consultants can verify; the purpose of our visit is for observations of foundation
bearing conditions only. Appropriate design professionals should be consulted regarding
crawlspace ventilation, building material selection and mold prevention issues, which are outside
GeoPacific's area of expertise.
We have prepared this report for Ichijo USA, and it should not be relied upon by third parties without
consulting GeoPacific. Within the limitations of scope, schedule and budget, GeoPacific attempted
to execute these services in accordance with generally accepted professional principles and
practices in the fields of geotechnical engineering and engineering geology at the time the report
was prepared. The conclusions and interpretations presented in this report should not be construed
as a warranty of the subsurface conditions.
No warranty, expressed or implied, is made. The scope of our work did not include flood hazard
evaluations, environmental assessments, the presence or absence of wetlands; or potential
hazardous substances in the soil, surface water, or groundwater at this site.
We appreciate this opportunity to be of service.
Sincerely,
GEOPACIFIC ENGINEERING, INC.
s
wr ,.
; y .' eel;
Benjamin G. Anderson, P.E.
Associate Engineer