Ltr Response to Cmts Rvw 2 012408~V~I~i_n
'• _ -
JAN 24 2008
H A T T O N G O D A T P A N T I E R
January 23, 2008
Mr. Jim Gibson
City of Yelm
105 Yelm Avenue West
Yelm, WA 98597
RE: Del's Farm Supply- SPR-05-0673-YL, HGP #05-055
Civil Construction Review #2
Dear Mr. Gibson:
I am writing in response to your comment letter dated October 23, 2007, regarding the
second civil review for the above referenced project. My responses to your comments
are itemized below:
Water Comments:
1. We have added the following note to the plans: "Developer is responsible for the
cast of fire hydrant locks and the City of Yelm Water Department will order and
install the locks." We have notified our client regarding the cast.
2. The connection to the existing watermain on Bald Hills Road has been revised to
a Hot Tap.
Sewer Comments:
3. The STEP system had been revised to a Simplex system.
4. Anew hose bib has been added to assist in the maintenance of the septic
system.
5. The details have been revised to match the most current Development
Guidelines.
6. Thrust blocks have been added to the tap callout.
7. The STEP line has been revised to show it coming out of the front of the STEP
tank.
8. Rim and bury depth have been added to the STEP Tank callout on Sheet 8.
9. The City of Yelm standards far sewer installation are located on the overall Utility
Plans, Sheet $ and the details on Sheet 10.
10. The cleanout detail is located on Sheet 11.
Engineering Comments:
11. The pond has been redesigned as a detention pond which does not have a depth
groundwater requirement.
12. Wet ponds are not required to meet the depth to groundwater; we have also
added a liner per Jim Gibson's request.
13. The pavement design is enclosed. ne„o~ aoae~ ve~vre,, m~.
i8A0 Bamas Blvd SW
Tumwater WA 90512
T 360 943.1599
F 360.35].6299
A 00]00 1693
encirveexs nmo saavEyp pS hattan pa nPianwm
Del's Farm Supply - SPR-05-0673-YL, HGP #05-055
January 23, 2008
Page 2
14. Wet ponds and detention ponds do not need to meet the same separations
requirements.
15. The STEP line has an end of line cleanout.
16. cleanout detail is shown on Sheet 11.
17. Backflow devices have been added to the callouts for the water meters
18. Drainage report has been revised to match plans.
19. The reference to the oil/water separator has been removed.
Planning Comments:
20. The pond has been revised to minimize construction in the 200-foot shoreline
jurisdictional area. Only the flow spreader remains in the shoreline jurisdictional
area. Total estimated cost for the pipe and spreader is $2,017. Please see the
table below:
Shoreline Construction
Item Unit ~~' Quantity I Unit Price Amount
Spreader CY 67 4.00 267
Storm pipe (8-15 inches) LF 70 25.UU 1,/ou
Sub-total $2,017
21. The City of Yelm Street Tree Planting Detail has been added to the Landscape
Plans.
If you have any questions or require additional information, please feel free to call me at
(360)943-1599.
Sincerely,
HATTON GODAT PANTIER
/~/ W
D'avi~. Sp Iler, PE
Senior Project Engineer
DWS:jIc
Enclosures: Two Copies of the Revised Drainage Report, dated 1/23/08
Four Full-Size Copies of the Revised Landscape Plans, dated
Four Full-Size Copies of the Revised Utility Plans, dated 1/23/08
One Copy of Soils Investigation by Bradley-Noble Geotechnical Services,
dated 1/21/08
cc: Linda Michaelis, Del's Farm Supply, PO Box 682, Yelm, WA 98597
Engineering Correspondence File 05-055
E:\oHice\JOBS\2005105-055-Ders Farm Supply-Velm\LTR-Gibson-0123.OB.doc
Bradley-Noble Geotechnical Services
A Division of The Bradley Group, Inc.
PO Box 12267, Olympia WA 98508-2267
Phone 360-357-7883 • FAX 360-867-9307
21 January 2008
Mr. David Spiller, P.E., Project Engineer
Hatton Godat Pander, Inc.
1840 Barnes Boulevard SW
Tumwater, Washington 98512
Subject: Subgrade investigation for pavement design at the Del's Farm Supply
Store, 10616 Bald Hill Road SE, Yelm, Washington.
Dear Mr. Spiller
As requested, we have conducted a subsurface investigation to determine subsurface
stratigraphy at this site. From our understanding of the proposed project, a new storm
water infltration structure will be constructed east of the existing facility and the creek
to the east near the east property line. New asphaltic concrete pavement will be
constructed in the area south and east of the existing propane tank and east of the
existing storage building. Anew gate to the property with a driveway will be
constructed to access the property from Bald Hill Road SE.
Our work consisted of the excavation of two test pits using grubber-tracked mini-
excavator on 7 January 2007. Soils exposed were logged and representative soil
samples from Test Pit Two were obtained for laboratory testing to determine soil
classification. Both test pits were loosely backfilled prior to our leaving the project site.
We encountered the typical soil pro0le for this area. The upper soils have the Soil
Conservation Service (SCS) classifcation of the Spanaway Topsoil unit. This is a gravelly
silty sand with organics. At this project area, we found these soils to be thinner than
typical, less than I.5 feet in thickness. Underlying the topsoil unit are the coarse sands
and gravels with cobbles and boulders of the Vashon recessional outwash. The test pits
were terminated in the outwash sands and gravels. The thickness of the outwash varies,
but is greater than ten feet in the project area.
08011401
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Page 2 of 3
The Spanaway topsoil unit is a poor subgrade material with a Uniform Soil Classification
of SP. This soil contains finely disseminated organic material and a sufficient percentage
of silt size particles chat this soil unit will "mud up" when exposed to rain and
construction traffic. We noted that areas of the existing pavement were failing.
Examination of these areas suggest that the pavement was placed directly onto the
Spanaway soils. The poor subgrade reaction and moisture sensitivity is the probable
cause of the localized pavement failure.
The soil sample for the Vachon recessional outwash is skewed to the finer size. In our
sampling, we did not include the oversized cobbles found in this soil section. This soil
has a Uniform Soil Classification of GP. This soil is suitable for support of pavement
sections. Using the data in the Thickness Design Manual of the Asphalt Institute the GP
soils of this site may use a design CBR value of 30 based on soil classification.
To construct new pavement sections, we recommend that the Spanaway topsoil unit be
removed to expose the dense, free-draining soils of the Vachon recessional outwash.
With the indicated construction of dikes for the new storm water pond, the excavated
Spanaway soils may be used for this construction. The exposed outwash soils are to be
proof-rolled to densify these soils and improve the subgrade reaction. Standard density
testing of these soils is not possible due to the excess of material retained above the'/.-
inch screen. The development of a firm and non-yielding surface may be used for
evaluation of the proof-rolling and for control of the placement and compaction of the
subgrade material.
Excavated outwash soils from the storm pond excavation are suitable for construction
of the subgrade material to bottom of the structural section in new driveway and
parking areas. The oversized cobbles and boulders will need to be removed from the
subgrade material in order for this material to be used as subgrade material. The
project civil engineer will specify the maximum patticle size to be allowed. Onto the
subgrade material, we recommend a structural section of two inches of compacted 5/8-
inch minus crushed rock (top coarse) and two inches of compacted class B asphaltic
concrete pavement.
If we may be of additional service to you on chic project, please contact us at our
Olympia offce.
08011401
Page 3 of 3
Cordially,
BRADLEY-NOBLE GEOTECHNICAL SERVICES
~~Q~C'
David CC. o
Enclosures: Site plan with approximate cent pit locations. oP >>~ p,`
Test Pit Logs. ~Setl Geo~o
Laboratory test data. DgVID C. STRONG
TEST PIT LOGS
Del's Farm Store, Yelm
Test Pit One:
0 to - I.I feet Dark brown gravelly silty sand with roots.
- I.I to -4.5 feet Yellow-brown sandy gravel with cobbles.
Test Pic Two:
0 to -1.4 feet Dark brown gravelly silty sand wich roots.
-1.4 to -4.9 feet Yellow-brown sandy gravels with cobbles and occasional boulders.
The mini-excavator had difficulty excavating the test piu due to soil density and
oversized material.
06011401
Test Pit Logs
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H`JI3M AD ONISSb'd 1N30ii3d
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~"~\ SIEVE ANALYSIS RESULTS
I
NC.
INSIGNT GEOLOGIC,
\~~~ FIGURE
Particle Size Analysis Summary C1ata
Job Name: Del's Farm Supply
Job Number:
?ested By: Insight Geclogic
Date: January ?0, 2008
Boring #: N/A _
Sample #: 2
Depth:
Moisture Cantenif%~ ~~~
Sieve Size Percent,
Passing (°i°)
3D in. X75.0' t00.C
1 5 in_~5~_ 100.01
3~4 in. 19.0 100.0
3/8 in. 9.5-mm 80.8
No.4 4.75-mm 57.2
No. 10 2.00-mm 45.6
No. 20 .850~~mm 31.8
No. 40 .425-mm 17.6
No. 60 .250-mm 9.3
No. 100 .150-mm 6.1
No. 20D .075-mm 4.5
Size Fraction Percent by
Weight
Coarse Gravel 0.0
Fine Gravel 42.8
Coarse Sand _ 11.6
Medium Sand 28.0
Fine Sand 13.1
Fines 4.5
Total 100.0
LL
PI
Dia 0.3
D3° 0.85
Dso 0.45
D9o 12
Cc 5.35
Cu 1.5
ASTM Classifcation
Group Name Poorly Graded Sand
Symbal SP
Particle Size Analysis Summary Qata
Job Name: Del's Farm Supply F3oring #: tJIA __
Job Number. Sample#: 1
Tested 6y: Insight Geelogic Depth:
Dc ~: January 10, 200E
Moisture Content(%; i 11.8°!„
Percent by
Size Fraction Weigh?
C
I
oarse Gravel
r 31.8
me Gravel
___ 21.9
_-
I
CoareSand 8~1
Medium Sand ifi.8
~ine
Sand 12.6
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Fii nes
m- 8.8
ra
_ __.ioac,i
LL
PI
Dio 0.09
D>c 0.95
Dao 11
Dso 20
Cc 0.91
Cu 122.22
ASTM Clas=_ifcaron
__
Group Name Poorly Gratled Gravel
Symbol GP
Sieve Size Percent
Passing (%)
3A in. (75.0) 100.C
1.5 ir,. (37.5) _ i00.G
3,'4 in. 19.0) _ 68 2
318 in 9.5-rnmt__ 582
No. 4 (4.75-mm) 40.3
No. 10 (2.00-mm)_ 38.1
No. 20 (.850-mm 29.5
No..10 (.425-mom
tJO. GO (.250-mm?~ 21.4
_ iFi2
'No 100 L150-mn~_ 12.5
Nc_200 (_075-mn~_ 8.8