HomeMy WebLinkAboutB13-0033 B13-0034 gravel borings ``LKP `: Engineering, Inc.
CIVIL/GEOTECFINICAL
SOIL AND FOUNDATION INVESTIGATION
FOR A PROPOSED DUPLEX
LOT 10, BLOCK 2, VAIL VILLAGE FILING NO. 12
3080 BOOTH FALLS COURT
TOWN OF VAIL
EAGLE COUNTY, COLORADO
PROJECT NO. 12059
OCTOBER 23, 2012
PREPARED FOR:
PETER DOBYNES
C/O ALAN STYERS
SCI FRAMERS, INC.
P.O. BOX 678
SNOWMASS, CO 80654
P.O. Box 2837, Edwards, CO 81632 Tel (970) 926-9088
TABLE OF CONTENTS
EXECUTIVE SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SCOPEOF STUDY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SITE DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
PROPOSED CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
FIELD INVESTIGATION.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SUBSURFACE SOIL AND GROUNDWATER CONDITION.. . . . . . . . . . . . . . . . . . . . . . . . . . 3
FOLJNDATION RECOMMENDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
EXCAVATION DIFFICULTIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
SLAB CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
RETAINING WALLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
UNDERDRAIN SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SITE GRADING AND DRAINAGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
LAWN IRRIGATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
LIMITATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
FIGURES
LOCATION SKETCH . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . DRAWING NO. 1
SUBSURFACE EXPLORATION LOGS. . . . . . . . . . . . . . . . . . . . . . . . . . . FIGURE NO's 1 - 2
GRAIN SIZE DISTRIBUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FIGURE NO's 3-4
PERIMETER DRAIN . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .FIGURE NO. 5
LKP Engineering, Inc.
2
EXECUTIVE SUMMARY
The proposed duplex should be supported
on the undisturbed firm sandy gravel, below any topsoil,
with conventional type spread footings, designed for a
maximum allowable soil bearing pressure of 3000 psf.
See Foundation Recommendations.
SCOPE OF STUDY
This report presents the results of a subsurface Soil and Foundation Investigation for a
proposed duplex to be constructed at Lot 10, Block 2, Vail Village Filing No. 12, 3080 Booth
Falls Court, Town of Vail, Eagle County, Colarado. The purpose of the subsurface soil and
foundation investigation was to determine the engineering characteristics of the foundation soil
and to provide recommendations from a Geotechnical point of view for the foundation design,
grading, and drainage. Geologic hazard Studies are outside of our scope of services.
SITE DESCRIPTION
Lot 10 is a 0.392 acres lot, at 3080 Booth Falls Court, in the Town of Vail, Eagle
County, Colorado. The topography of the parcel is moderate. Drainage is to the south. Vegetation
on the parcel consisted of wild grass on the lower and south part of the lot and aspen forest on the
upper part. There is an existing residence on the lot to the east. To the south there are a parking
]ot and a cabin. To the north is Booth Falls Court, while to the west is Booth Falls Road. The lot
is vacant.
LKP Engineering, Inc.
3
PROPOSED CONSTRUCTION
We have assumed that the proposed residence will consist of two stories, wood frame
construction, with a basement on a concrete foundation. We anticipate loads to be light, typical
of residential construction
When plans have been developed, we should be notified to reevaluate the
recommendations of this report.
FIELD INVESTIGATION
The field investigation, conducted on October 18, 2012, consisted of drilling, logging
and sampling two test bores. The test bore ]ocations are shown on Drawing No. 1. Drilling of the
test barings was done with a 4-inch diameter, a continuous flight power auger on a track
mounted, drill rig. Soil samples for laboratory soil analysis and observation were taken at
selected intervals with a California and Split Spoon Samplers, advanced with a 140-pound
hammer, falling 30 inches.
We show the soil profiles of the test borings on the Subsurface Exploration Logs, Figure
No's one and two. Soil samples for laboratory soil analysis and observation were taken at
selected intervals.
SUBSURFACE SOIL AND GROUNDWATER CONDITION
The soil profiles encountered in the test bores were fairly uniform. Boring No. 1 had one
foot of topsoil over approximately two feet of gravelly sand over light brown, silty to clayey,
gravelly, sandy matrix with very large boulders to the maximum depth explored of about 9 feet,
at which refusal was encountered. Four additional attempts were made to penetrate below the
boulders within a 13 to 15-foot radius of the boring location. Refusal was encountered in all
attempts.
Boring No. 2 had four feet of topsoil underlain by about two feet of dark brown, gravelly
LKP Engineering, Inc.
4
sand over light brown, silty to clayey, sandy gravel with cobbles and large boulders. Refusal was
Ground water was not encountered in the borings during the drilling.
The thickness of the individual soil layers will vary, since the description is based on the
observation of the extracted soil samples. We sampled the soil in the test borings at random
intervals. The soil samples were brought to our laboratory for observation and analysis. They
were tested for natural moisture content and grain size distribution, as shown on Figure numbers
three and four.
FOUNDATION RECOMMENDATIONS
The proposed structure should be supported with conventional type spread footings,
designed for a maximum allowable soil bearing pressure of 3000 ps£ The footings should be
placed on undisturbed sandy gravel with cobbles and boulders, below all topsoil and unsuitable
soil. The entire foundation must be sup�orted on the sandv��'avel with cobbles and boulders.
The undersigned engineer must observe the foundation excavation to verify that the soil
conditions are as anticipated based on the information fYOm the two test borings. For any
additional foundation alternatives,please contact our office.
Continuous foundation walls should be well reinforced, top and bottom, to span an
unsupported length of at least 10 feet. A minimum backfill cover, as required by the local
building department, should be provided for frost protection of the footing subsoils.
The foundation excavation should be free from excavation spoils, frost, organics and
standing water. Any overexcavation within the proposed foundation, should be backfilled, in 8
inches loose, level lifts and compacted to 98°/o of the maximum dry density and within 2 percent
of the optimum moisture content as determined in a laboratory from a Standard Proctor test
(ASTM D-698). Structural fill,placed under footings, should be tested by a qualified
professional on regular basis. Contact the engineer before placing any structural fill.
The on-site soil free from topsoil, organics, and rock fragments smaller than six inches, is
suitable backfill material. Voids left in the excavation, due to rock removal, should be fi11ed with
lean concrete or clean crush rock, approved by the engineer. The footings should be constructed
LKP Engineering, Inc.
5
on a level surface.
EXCAVATION DIFFICULTIES
From the condition of the large sandstone boulders observed in the test pits, we assume
that the excavation can be done with large excavation machinery. Excavation of narrow utility
trenches might be more difficult.
SLAB CONSTRUCTION
The natural on-site soils, exclusive of topsoil and organics, are suitable to support lightly
loaded slab-on-grade construction. The subgrade for the slab-on-grade construction should be
proof compacted to detect and remove soft spots. They should backfill overexcavated soft spots
and other underslab fill with the on-site soil, free from topsoil and organics, or other suitable
material, compacted to a minimum of 95 percent of the maximum standard Proctor density
(ASTM D-698). Suitable material should be free from topsoil, organics and rock fragments
greater than 3 inches, approved by the undersigned engineer.
The concrete slab should be constructed over a 4-inch layer of clean gravel consisting of-
3/4 inch gravel with at least 50% retained on the No. 4 sieve and less than 3 percent passing the
No. 200 sieve.
They should reinforce the concrete slab-on-grade and score contro]joints according to the
American Concrete Institute requirements and per the recommendations of the designer to reduce
damage due to shrinkage. The concrete slab should be separated from the foundation walls and
columns with expansion joints to allow for independent movement without causing damage.
RETAINING WALLS
Foundation walls retaining earth and retaining structures that are laterally supported
should be designed to resist an equivalent fluid density of 55 pcf for an "at-rest" condition.
LKP Engineering, Inc.
6
Laterally unrestrained structures, retaining the on-site earth, should be designed to resist an
equivalent fluid density of 35 pcf for the "active" case.
The above design recommendations assume, on site soil, drained backfill conditions and a
horizontal backfill surface. Surcharge loading due to adjacent structures, weight of temporary
stored construction materials and equipment, inclined backfill and hydrostatic pressure due to
undrained backfill should be incorporated in the design. They should try to prevent the buildup of
hydrostatic pressure behind the retaining wall.
Passive earth pressure of 450 psf can be used for the lateral pressure against the sides of
the footings. Resistance to sliding at the bottom of the footings can be calculated based on a
coefficient of friction of 0.6. Undisturbed soil or a structural fill compacted to 100 percent of the
maximum dry density and within 2 percent of the optimum moisture content shall be used to
resist lateral loads at the sides of the footings.
UNDERDRAIN SYSTEM
Ground water was not encountered,but it is possible far ground water to fluctuate with
the seasons and rise during spring runoff or wet seasons. If ground water is encountered during
construction, we should be contacted to provide additional recommendations for temporary or
permanent ground water dewatering.
To reduce the risk of surface water infiltrating the foundation subsoil installation of a
foundation perimeter drain is recommended (see Figure No. 5). The foundation perimeter drain
should consist of a 4-inch diameter perforated pipe sloping to a suitable gravity outlet, or to a
sump pump location. If a sump pump discharge is selected, it's location must be tested, designed
and approved by the engineer. The drain should slope at 1/4 inch per foot if flexible or at 1/8 of
an inch if rigid pipe is used. The bottom of the trench adjacent to the footing should be lined with
a filter fabric. The drain pipe should be placed over the fabric and covered with a minimum of 6
inches of-3/4 inch free-draining granular material. Geotextile (Mirafi 140N or equivalent) should
be used to cover the free-draining gravel to prevent siltation and clogging of the drain. The
backfill above the drain should be granular material to within 2 feet of the ground surface to
LKP Engineering, Inc.
�
prevent a buildup of hydrostatic pressure. The top one foot of the backfill material should consist
of a relatively impervious fill. The backfill should be sloping away from the duplex.If�ground
water is encountered, the above perimeter drain would have to be revised accordingly.
SITE GRADING AND DRAINAGE
The following recommendations are general in nature. The site surrounding the duplex
structure should slope away from the duplex in all directions. A minimum of 12 inches in the
first 10 feet is recommended in unpaved areas, and three inches in the first 10 feet in paved areas.
The top of the granular foundation backfill should be covered with a minimum of one foot of
relatively impervious fill to reduce the potential of surface water infiltrating the foundation
subsoils. Exterior backfill should be compacted at or near the optimum moisture content to at
]east 95% of the maximum standard Proctor density under pavement, sidewalk and patio areas
and to at least 90% of the maximum standard Proctor density under landscaped areas.
Mechanical methods of compaction should be used. Do not puddle the foundation excavation.
Surface water naturally draining toward the proposed duplex site should be diverted
around and away from it by means of drainage swales or other approved methods. The roof
drains and downspouts should extend and discharge beyond the limits of the backfill.
Permanent, unretained cut and fill slopes should be graded at two horizontal to one
vertical or flatter with slope heights not eXCeeding 20 feet. Slopes exceeding 20 feet should have
benching incorporated. To protect the newly created slopes, erosion control methods should be
used. Also, drainage of the site above the slopes should be controlled to prevent slope instability.
If water seepage is encountered during the slope construction, additional studies will be required
to evaluate the slope stability.
LAWN IRRIGATION
It is not recommended to introduce excess water to the foundation soils by installing
sprinkler systems adjacent to the duplex. The installation of the sprinlcler heads should insure that
LKP Engineering, Inc.
8
the spray from the heads will not fall within 10 feet of foundation walls,parches or patio slabs.
Lawn irrigation must be controlled.
LIMITATION
This report has been prepared according to locally accepted professional Geotechnical
engineering standards for similar methods of testing and soil conditions at this time. There is no
other warranty either expressed or implied.
The findings and recommendations of this report are based on field exploration,
laboratory testing of samples obtained at the specific locations shown on the Location Sketch
Figure No. 1 and on assumptions stated in the report. Soil conditions at other locations may vary,
which may not become evident until the foundation eXCavation is completed. If soil ar water
conditions seem different from those described in this report we should be contacted immediately
to reevaluate the recommendations of this report.
This report has been prepared for the exclusive use of Peter pobynes, c/o, Alan Styers,
SCI Framers, Inc., Town of Vail, Eagle County, Colarado.
Sincerely,
LKP ENGINEERING, INC.
Luiza Petrovska, PE
J:\ WP X4-LKP\ 2012\12059gravel-borings.RPT.wpd
LKP Engineering, Inc.
Bo��� FALL
S C�UR�
LOT 10
BORING-1
O
< �
� � LOT 9
�
cQ"
^�
�"�i
� BORING-2
'� O
VMS
NOTEe THE LOCATION OF THE TEST BORINGS IS
APPROXIMATE. IT IS NOT BASED ON A SURVEY.
LOCATION SKETCH
CIVIL/GEOTECHNICAL PRa,ECT NQr 12OJr'9
LKP Engin eering, In c. LOT 10, B 30 0 BOOTH ALLS R ADNG N0. 12 ��� N '„ _ 40,
P.O. Box 2837 Edwards, CO 81632 VAIL, EAGLE CWNTY, COLORADO p�pAINNG Nar
tel (970) 926-9088 Email:lkpengOcenturytel.net 1
DATE OBSERVED: OCTOBER 18, 2012 BORING N0. 1
ELEVATI ON:
S S
Y A
DEPTH BLOWS M M DESCRIPTION OF MATER/AL LABORATORY REMARKS
FEET PER FT. B P AND SAMPLE L OCA 770N TEST RESUL TS
0 L
L E
TOPSOIL
BROWN, GRA 1/ELL Y SAND
4�/�2 :`�� ■ LIGHT BROWN, CLA YEY, SANDY
GRA I/EL WITH COBBLES AND MC= 3.89'
s `� 1/ERY LARGE BOULDERS —200=53.79'
r>Vri
-__�:
, .d
�.�:.:-:�3.
REFUSAL � 9 feet No Ground Water
�� Encoun tered
15
20
25
LEGEND:
0 — 2—inch O.D. Califo�nia Line� Sample DD — Natural Dry Density (pcf)
■ — Split Spoon MC — Natural Moistu�e Content (%)
24/12 — Orive sample blow count. lndicafes that 24 blows —200 — Percent Passing No. 200 Sieve
of a 140—pound hammer falling 30 inches were LL — Liquid Limit
required to drive the California o� the Split Spoon Pl — Plosticity lndex
Sompler 12 inches. GW — Ground water
PRObECT NQe
LKP ENGINEERING, INC. SUBSURFACE EXPLORATION LOG �2oss
�ax�Na: �
DATE OBSERVED: OCTOBER 18, 2012 BORING N0. 2
ELEVATI ON:
S S
Y A
DEPTH BLOWS M M DESCRIPTION OF MATERIAL LABORATORY REMARKS
FEET PER FT. B P AND SAMPLE LOCA TION TEST RESUL TS
O L
L E
— TOPSOIL
��
s/�2 0
s F�:` DARK BROWN, GRA I/ELL Y SAND
� ,
:�.
— �;. .
�� LIGHT BROWN, CLAYEY, SANDY
r�` + GRA 1/EL WITH COBBLES AND
— �°: 1/ERY LARGE BOULDERS
.;`, ..
— �� Boulder � 9'
�.,;.
�, ;
,o -,�
�y;':
o.
r,":
_ ;�.°
J�,;.,,
— ,`
�.
—.a_.
50/�2 G,, ■ MC= 6.5 9
15 0,.
REFUSAL � 15 feef No Ground Water
— Encoun tered
20
25
LEGEND:
0 — 2—inch O.D. California Line� Sample DD — Notural Dry Density (pcf)
■ — Split Spoon MC — Natural Moisfure Content (�')
24/12 — D�ive sample blow count. lndicates thof 24 6/ows —200 — Percent Passing No. 200 Sieve
of a 140—pound hammer falling 30 inches we�e LL — Liquid Limif
required to drive the Califo�nia o� the Splif Spoon Pl — Plasficity lndex
Sampler 12 inches. GW — Ground water
PRQ,ECT NQa
LKP ENGINEERING, INC. SUBSURFACE EXPLORATION LOG 12059
Flai�nro.: 2
Percent Coarser by Weight
p � N � � � � � � o�i �
O
O
O
O
O
O �
+r U �n
`� o � �
tl� +.. � ,
.,, (n �
O �
� �
C
^ � � `o
z
� �
.c Q o 3
� O .`
O
m � O
N �
� g o �',
�` $ o
�
� � ,�,
o >
� o
� °'
�
� Q .o N �i,
my o C O
N � � � V
2 b � � O `�
�u � � � �
� � 3
e � y m
2 �o �
O
t~i� U
� � h
� �
� O �
S �
� �
� � n
0
� �
2 C � O
O
2 N � U �
W
h
� w O �
� "i
�
o� +'
aci
2 � vr
ti .�p O
y o v
�
� � �
� o�i � � � � � � N � � �
'o
Percent Fine� by Weight �
�cr Na
LKP Enginee�/ng, lnc. GRAIN—SIZE DISTRIBUTION ����1205�
Percen t Coarser by Weigh t
p � N � � � c�o � � o�i �
�
O
O
O
O
O
O 0
� U
� � �
^ o o� y
'� '� a�i
.,,, � � O
O y ,
N � c .°o
o �' �`
Z � o,
.c �x o �
m � �
g =
�
o ° " 3
� o
� $ >
0
o � o,
o � b�
� O
g � �
� �
M � e N �
� N � , C �
2 � ^ � � �
� � � � •�
� ° 3
e � y m
Z �a o
ti O
t� � U
�3 �
� �
� O �
�
S �
O
�
� o �
c�
2 s � o
0
2 N h U �
M
� V� O �
� �
�o
O� "..
�
e
y O C�
�
� � �
� o�i � � � � � � N � � �
0
Percen t Finer by Weigh f �
PR0.ECT N0.
LKP Engjnee�Ing, lnc. GRAIN-SIZE DISTRIBUTION Flq/�/y�12O59
4
SLOPE AWAY FROM BUILDING
D . 6 �p
d
> . OVER BACKFILL WITH TWO FEET
° o OF RELA TIVEL Y IMPER liIOUS SOIL
p A ' D
o D
�,
d
P
D' -
n J� � -
o \ D _ -
S -
'� D - " - ' " _ _ _
b = - -
. D.O . - _ ' . /
� a - - " �
a ' " - _
_ _/
.. Q 'D ' ' _ " \
D - . .. _._ - - �
Q _ - _ _:::. '/
,Z _ _ GRANULAR`FILL y _ �
� . :�:::.:
•: � ::-.'
..
n D -.>' _
. . . . ::_.......:.._.r.... i
� :b - - - - - " _
- - _ �/
n , -
. �
e o . � .: - - lL TER FABRIC (MIRAFI
- _ - - - 140N OR EQUIVALENT)
D �. '
�D �c �. ' - - -
. . _ QD.. A' .D. . ..p . • . .O:.O..�.: .�.'. ..-.i.'.,. .
p ' ' ' . . . � Q' . . � ,•.::-..'.�: `
° FOOTING ° �0�. 0�. =::" �
..p � � . . . Q',• .'p•�•• • • \
, ��.�:�o� �� � � ��C'�.���
. D ' '. D . .. Q,' ',' .' /
�D �� ' . . . D . . .�n ..o�p� � '�.�..� ' • ' • \
� •�Q. �:.p.Q� \�
!\ /.\ /.\ /.\ /,\ /.\ /. � � �
���\ //\ MINUS 3/4—INCH DIAMETER, COARSE,
CLEAN CRUSH ROCK
FlL TER FABRIC, M/RAFI 140N —INCH DIAMETER PERFORA TED PIPE
OR EQUIVALENT SLOPED TO A DAYLIGHT LOCA770N AWAY
FROM THE FOUNDA TION A T 1/4—INCH PER
FOOT FOR FLEXIBLE AND 1/8—INCH
MlNIMUM FOR RlGID PIPE
NOTE: THE LOCATION OF THE TEST PITS IS
APPROXIMATE. IT IS NOT BASED ON A SURVEY.
PERIMETER DRAIN
CIVIL/GEOTECHNICAL PRa,ECT NQr 12OJr'9
LKP , Engin eering, In c. LOT 10, BL3 80 BOOTH FA LS ROADNG N0. 12 scu� N.T.S.
P.O. Box 2837 Edwards, CO 81632 VAIL, EAGLE CWNTY, COLORADO FlAUR£NQ:
tel (970) 926-9088 Email:lkpengOcenturytel.net 5