Report Voiutions l ncl o►J
CITY Cc TIr,ARD
May 29, 2014 i,m aG',,%o oa5 1 ili phoenixredev-14-2-gi
Phoenix Redevelopment -
jonl W..phoenixredevelopment.com
SUMMARY OF GEOTECHNICAL SERVICES
Infiltration Evaluation, 9880 SW Sattler- Tigard, OR
We appreciate the opportunity to present this summary of our geotechnical services for the subject
infiltration evaluation. From our communications we understand the site is to be redeveloped for
several lots with an access easement/drive to the east. Infiltration rates are needed to evaluate shallow
on-site storm water system design by others. Our scope of work included the following:
Provide principal-level project management including client communications, management of field
and subcontracted services, report writing, analyses, and invoicing.
Review previous reports, geologic maps and vicinity geotechnical information as indicators of
subsurface conditions.
Complete a site reconnaissance to observe surface features relevant to geotechnical issues, such as
topography, vegetation, presence and condition of springs, exposed soils and rock, and evidence of
previous grading.
Explore subsurface conditions with two test pits advanced to a depth of up to 8 feet or refusal using
a small track mounted excavator. Provide a water tank and casing for infiltration testing.
Complete open hole or cased hole falling head infiltration testing in the explorations, and provide
infiltration rates to the civil engineer for their system design, including related geotechnical material
and embedment recommendations.
Classify and sample materials encountered and maintain a detailed log of the explorations.
Provide a written letter report summarizing the results of our geotechnical evaluation.
Subsurface Conditions
We completed our geotechnical explorations on May 28, 2014 using a small rubber-track mounted
excavator by excavating two test pits to depths of up to 8 feet. Our test pits are approximately located
on the attached Site Plan. Subsurface conditions consisted of soft to stiff silt with angular basalt
fragments at depth in TP-2. Slow seepage was observed at a depth of 7 feet in TP-2. No caving was
observed in our exploration.
Infiltration
Falling head infiltration testing was completed at depths of approximately 3.5 to 4 feet in each
exploration, using a double ring standpipe configuration and falling head measurements after initial
saturation and up to 2 feet of head. Raw results are listed in the Attached Test Pit Logs. Based on the
results of our testing and analyses we recommend using a design infiltration rate of 0.8 cubic inches per
hour per square inch (this includes a reduction factor of 2 applied to the average of the test results)
applied to the sides of systems, with the base also used if the upstream collection system is protected
from sedimentation.
1/2
1 112 7th Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946
May 29, 2014 phoenixredev-14-2-gi
Trench systems must be protected from silt intrusion with the use of non-woven geosynthetics, such as
a Propex Geotex 601 or equivalent. Rock for system fill must be open graded and contain no more
than 2%fines.
Field Testing
As actual subsurface conditions and infiltration can vary widely, testing of infiltration systems is required
to confirm this preliminary estimate. Flexibility for adaptation of infiltration systems should be planned
into the design and construction, with contingencies built into the budgets and schedules. Infiltration
systems need to be maintained free of debris and silt in order to function properly.
Limitations
We have prepared this report for use by Phoenix Redevelopment and members of the design and
construction teams for this project only. The information herein could be used for bidding or estimating
purposes but should not be construed as a warranty of subsurface conditions. We have made
observations only at the aforementioned locations and only at the stated depths. These observations do
not reflect soil types, strata thicknesses, water levels or seepage that may exist between observations.
We should be consulted to observe all excavations for infiltration systems. We should be consulted to
review final design and specifications in order to see that our recommendations are suitably followed. If
any changes are made to the anticipated locations, configurations, or construction timing, our
recommendations may not be applicable, and we should be consulted. The preceding recommendations
should be considered preliminary, as actual soil conditions may vary. In order for our recommendations
to be final, we must be retained to observe actual subsurface conditions encountered. Our
observations will allow us to interpret actual conditions and adapt our recommendations if needed.
Within the limitations of scope, schedule and budget, our services have been executed in accordance
with the generally accepted practices in this area at the time this report was prepared. No warranties,
expressed or implied, are given.
< >
We appreciate the opportunity to work with you on this project. Please call if you have any questions.
Sincerely,
V a li It
•
Don Rondema, MS, PE, GE "
Principal anal
ROWet
Expires t?Af 11+i 1
Attachments: Site Plan, Classification Guidelines, Test Pit Logs, Moisture Contents
2/2
1 1 12 7th Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946
�i w Si,11 IIC SI SW Sattler Street
1
. y .gin „
.., .....,,... . J-,.-1 . , titer.St. Tigard OR 97224 USA
NIL , ,...
`4. 4 r
r
R. D
P;�a f.
4 om.
sir
4 Imp
�p 3. 3 No
T ^
f Y , : N . . ,
..1. ....ir I. x'
N
NOT TO SCALE
BASE FROM GOOGLE EARTH 2012 AERIAL
G t ch SITE PLAN
S o I Q U 1 0 n S I n C 1 phoenixredev-14-2-gi
•
GUIDELINES FOR CLASSIFICATION OF SOIL
Description of Relative Density for Granular Soil
Standard Penetration Resistance
Relative Density
(N-values)blows per foot
very loose 0-4
loose 4- 10
medium dense 10- 30
dense 30- 50
very dense over 50
Description of Consistency for Fine-Grained (Cohesive) Soils
Standard Penetration Torvane
Consistency Resistance(N-values) Undrained Shear
blows per foot Strength,tsf
very soft 0-2 less than 0.125
soft 2-4 0.125 -0.25
medium stiff 4-8 0.25 -0.50
stiff 8- 15 0.50- 1.0
very stiff 15 -30 1.0- 2.0
hard over 30 over 2.0
Grain-Size Classification
Description Size
Boulders 12-36 in.
Cobbles 3 - 12 in.
Gravel '/4- 3/4 in. (fine)
3/4-3 in. (coarse)
Sand No. 200- No.40 Sieve (fine)
No.40- No. 10 sieve(medium)
No. 10 - No.4 sieve (coarse)
Silt/Clay Pass No. 200 sieve
Modifier for Subclassification
Percentage of Other
Adjective
Material In Total Sample
Clean/Occasional 0-2
Trace 2 - 10
Some 10- 30
Sandy,Silty, Clayey,etc. 30-50
b
Test Pit# Depth (ft) Soil Description
Explorations completed on May 29, 2014 with small excavator
TP-I Location: E central portion of property
Surface conditions: Mowed grass
0.0-0.4 fof dark brown, rooty organic SILT with trace clay;moist(topsoil).
0.4-8 Soft to medium stiff, mottled orange and gray, brown SILT with trace clay and
occasional fine roots; moist.
2 feet-medium stiff, no roots
5 feet-stiff
No seepage. No caving. Infiltration test at 3.5 feet. Raw field rate 2 in/hr.
TP-2 Location: SE portion of property
Surface conditions: Mowed grass
0.0 -0.3 Soft, dark brown, rooty organic SILT with trace clay; moist(topsoil).
0.3 -7.5 Medium stiff, mottled orange and gray, brown SILT with trace clay and occasional
fine roots; moist.
1.5 feet-no roots
3 feet-stiff
5 feet-stiff
7 feet-with some angular basalt fragments
Slow seepage below 7 feet. Infiltration test at 4 feet. Raw field rate 1.2 in/hr.
te TEST PIT LOGS
J i u l i o n s Inc 1 phoenixredev-14-2-gi
J
Exploration Depth,ft Moisture Content
TP-1 2.0 20%
TP-1 4.0 25%
TP-2 4.0 27%
TP-2 6.0 27%
fle t,CJ'j MOISTURE CONTENTS
O V t I O n S Intl phoenixredev-14-2-gi
George,
Here is the Infiltration test I had done at the two homes on Sattler Street that you had requested.
Please let me know if you need anything else. I am hoping to get started on these right away as one of
the homes are sold and closing in a couple of weeks. I appreciate your help on this. Thanks.
Cale Doney pL GVl 0-7 - c>G .?8 / clog`( F w 5'4-77-e �t
Construction Manager PI 147 02 o(5_ oc' F',9'y-S • S w Ste?L t ✓�
Sage Built Homes, LLC
503-969-8298