HomeMy WebLinkAboutREPLAT LOTS 2 THRU 8 & KEGLER PARK PUDi4 ., I.
- • .. i
'TABLE OF CONTENTS
Table of Contents..ae�ge,.etl..00�...o.•o.e.s•,o.•es.•o,ea.o
Letter of Transmittal ee...m...,.e........q...e...q.,.......
�i
Report .. a. A ... e e e. e e. e s. e. O►. aa ..�► s s .. • w e O !.. e, ... O a s ... a .. .
. Appendix A...e...,...00eAeo.e.A.,ro•ssgo.eoose.ee.seseo.eeese
A-1
Test Boring Location Plan rawaoogs.o...e..,.s....s..eese..
A-2
Key to Oorings
A-3
Lag of Borings .........
A-4
Appendix 6............e.....tlee.e.....e..;.e......e.....d...
B-1
Consolidation Test Data.,a...O.Os.e..p.k................a
8-2
Summary of Test Result .ere. ,.e.gesa..oaeegoeos.,asosaaes
B—`!
/
' ppends x /. C e ...... • .. O. e .. e q O,O a .. 0 6 0 0 0 0 4. 0 .... q� ...... • .. e. A.
Appendix
C-1
i
E peeAboratories, Ime. Branch Offices
1242 Bramwood Place
MATERIALS AND FOUNDATION ENGINEERS Longmont, Colorado 80501
P.O. Box 1135
214 No. Howes Fort Collins, Colorado 80522 (303)'776-3921
P.O. Box 429 (303) 484.0359
xr
3151 Nation Way
NovembeA 2, 1979 _ Cheyenne, Wyoming 82001
P.O. Box 10076
(307) 632-9224
City o 6 FoAt Cott in6
300 LaPoAte Avenue
PoAt Co.ettin6, Cotonado 80521
Attention; on; M,%. John MCGAaW
Genttemens
We axe pZea.6ed to pusent oun nepoAt o6 a geote0mieat .invatigation 6oA
the ptopoa ed Ketgex PaAk Houb.ing pto je.c t. tocated zou th o f LaPoA,te
Avenue between Peace and Sh.i.eW6 Stoteet6.
Sued upon ouA p:nd nga, we jeeC tfuct the 6 to .i6 budtabte 6o,% the
pupoaed con6t4uCti.On, p4oviding the dea.ign etitexia and necommendation6
as bet 6oAA .in th 4 nepoxt aye met. The accompanying AepoAt p&uent6
ouA j ndingb .in the . a.b6ungace and ouA aecomme►adati.ona based upon these
Jtnd ing6•
Ven.y tku-Zy young,
EMPIRE LABORATORIES, INC.
M.ichaet J. CoweQ.0
Geotechnieat Engine `
�,1S,�fi'Yi� taBP•PP,
r A
Reviewed by:`�.�3��a-1,e'�,,
Chem C. Smith, P.E.
ft" ident
ce.s ZV1=K A�cch,iteet6
MEMBER OF CONSULTING ENGINEERS COUNCIL
REPORT
OF A
GEOTECHNICAL INVESTIGATION
SCOPE
This report presents the results of our geotechnical investigation
prepared for the proposed Kelger Park Housing project located south of
LaPorte Avenue between Pearl and Shields Streets. .The investigation was
carried out by means of soil ,test borings and 'laboratory testing of
samples obtained From these borings.
The purpose of this investigation was -to obtain subsurface In-
formation at the site in order that recommendations could be made rela-
tive to the proposed foundation and earthwork design.
SITE INVESTIGATION,
The field investigation, carried out on October 226 1979s consisted
of drilling seven (7) soil test borings. The.location ofeach boring is
shown"on the Test Boring Location Plan in Appendix A. Soil and ground-
water conditions encountered at each boring location are represented on
the boring logs enclosed in Appendix A.
Each boring was advanced with a four -inch diameter; -continuous -
type, power -flight auger. Standard penetration tests were performed in.
each boring. Soil samples. were obtained using two and one-half (2h).'
inch diameter Shelby tubes and a standard splitspoon sampler. During
drilling operationsq, a geotechnical engineer from Empire Laboratoriess
Inc. was present and made a continuous visual inspection of the soils
encountered. i
»1-
SITE LOCATION A140 DESCRIPTION
The site is located approximately one hundred thirty (130) feet
south -of LaPorte Avenue, between Shields Street and Pearl Street, in
Fort Collins, Colorado. A new.road, Jamith Place. has been proposed
which will intersect with LaPorte Avenue, run south and dead end in the
center of the site.
Presently a gravel road runs on the east side of the proposed
Jamith Place. Where the gravel road intersects LaPorte Avenue, it acts.
as a driveway between two (2) existing residences. The proposed site.is
located south of these residences and consists primarily of an open
field covered with tali weeds and grass. Rows of large trees presently
bonier the perimeter of the site, with the exception of the southeast
corner where the gravel road exits. A row of trees also traverse the
site running north to south approximately thirty (30) feet east of
Boring 5.
Northeast of Boring 2 and within the proposed building area, there
exists an abandoned foundation structure consisting of a concrete slab -
on -grade surrounded by continuous strip footings. To the southwest of
Boring 1, old strip footings were also observed.
The site topography is relatively level with less than a two (2)
foot difference in elevation between boring locations.
LABORATORY TESTS AND EXAMINATIONS.
Representative samples recovered.in test borings were selected for
tests in the laboratory to determine their physical characteristics and
engineering properties. Included in the test program were natural
moisture content, water soluble sulfates. Atterberg limits,.dry density,.
unconfined compressive strength, and consolidation testing. Laboratory
test results are sumrized in Appendix B.
SOIL AHO GROUNDWATER CORDITiONS
The following are the characteristics of the primary soil strata
encountered at the site.
(1) Topsoil The site is overlain by a layer of topsoil approxi-
mately six (6).to twelve (12) inches thick. The upper six (6)
inches have been penetrated by root growth and organic matter
and should not be used for foundation bearing or as backfill
material.
(2) Silty Clan: This stratuaa underlies the topsoil and exists to
a depth of approximately eight and one-half (8h) feet. The
stratum consisted of a tan -brown silty clay and clayey silt,
with a little fine sand. Standard penetration resistances
within this stratum ranged from two (2) to seven (7) blows per
foot, with an average of four (4).blows per foot overall.
Unconfined compression testing on representative undisturbed
samples taken from this stratum revealed it has a relatively
lour strength and therefore, low bearing characteristics. This
is in agreement with the relatively low penetration resi-
stances observed in the field. Consolidation testing has
revealed this stratum is relatively compressible.
(3) SARAY s lv,a This stratum consists of.a red -broom silty
clay with some medium fine sand and a trace of fine gravel.
It was encountered directly beneath the silty clay and ex-
tended -to the depths explored. Standard penetration resi-
stances within this stratum ranged from one (1) to eight (8)
blows per foot. This stratum exhibited relatively low bearing.
characteristics.
(4.) Groundwater: Water level readings and cave-in depths measured
at the time of the investigation and forty-eight (48) hours
later indicated that groundwater was ten (10) to thirteen (13)
feet below the ground surface. Fluctuations in the ground-
water level should be expected due to seasonal variations.
RECOWENDATIONS AND DISCUSSION
On -Site Structures
Prior to grading operations, existing foundation structures in
building and paving areas should be excavated and wasted from the site.
Excavations should be inspected by qualified geotechnical personnel to
see that all deleterious material has been excavated prior to fill
placement.
Fill in structure and paving areas should be placed at two percent
(2S) wet of optimum moisture content and compacted to a minimum of
ninety-five percent (95%) of Standard Proctor Density ASTM D 698-74.
(See Appendix C.) The on -site silty clay material is suitable for com-
pacted fill. It is recoumnded that additional off -sate fill required
should be a pit -run gravel material approved by a qualified geotechnical
engineer.
Site
The upper six (6) inches of existing topsoil should be'stripped
within proposed building and paving areas. The topsoil can be stock-
piled on the site and used for final grading outside of building and
pavement areas. Following topsoil stripping, the upper six (6)inches
of the subgrade should be scarified and recompacted in place at two
percent M) wet of the optimum moisture content and to a minimum of
ninety percent (90%) of Standard Proctor Density ASTM D 698.70. (See
Appendix C. )
-4-
Material excavated beneath the topsoil is suitable for compacted
fill in building and pavement areas. Additional off -site fill required
should be a pit -run material approved by a qualified geotechnical en-
gineer. rill in structure and paving areas should be placed at two
percent (c%) wet of optimum moisture content and compacted to a minis
of ninety-five percent (95%) of Standard Proctor Density ASTM U 698-70.
The fill should be placed in eight (8) to ten (10) inch lifts.
Qualified geotechnical personnel should be present to observe
%tripping.of the topsoil, scarification of the subgrade, and placement
and compaction of fill. In -place density tests should.be_taken in the
compacted subgrade and fill areas to insure proper compaction is ob-
tained.
Foundation
It is our understanding that the proposed structures will consist
of two (2) story frame, slab -on -grade multifamily units,
Based upon the loads transmitted by the proposed structures and
'the.subsurface conditions encountered at the site,, we recommend that the
structures be supported by conventional continuous or isolated spread
footings bearing in the natural undisturbed soil or approved compacted
fill. The undisturbed nature of -the bearing soil should be verified by
qualified geotechnical personnel.prior to placement of any foundation
concrete. All footings should bear a minim of thirty (30) inches
below exterior finished grades for frost protection. Footings bearing
st the above-wrecommended depths may be designed for a maximum allowable
soil pressure of one thousand five hundred (1500) pounds per square foot
ender dead plus maxim live loads.
The anticipated settlement under the above ,maximum bearing pressure
should not exceed 0.5 inch, considered to be within acceptable tolerances.
w
Slabs on Grade
The existing soils encountered at proposed subgrade elevation and
compacted fill are adequate for supporting normal floor loads on grade
provided they are. prepared in accordance with the "Site Grading" section
of this report.
All slabs on grade should be underlain by a minimum of four (4).
inches of .gravel or crushed rock free of fines. The gravel layer will
act as a capillary break and will help to distribute floor loads. To ,
minimize and control shrinkage cracks which will develop in slabs on
grade, it is suggested that control joints be placed every fifteen (16)
to twenty (20) feet and that the total area contained within these
joints be no greater than four hundred (400) square feet.
Pavement Sections
The required pavement thickness is primarily dependent upon the
groun&water, subgrade soil, and traffic conditions. AASHTO clAssifi-
cations of the anticipated subgrade soil are A-6(8) andA-4(8) both
with group indices of 8. Based upon a group index of 8,the groundwater
conditions encountered at the site and the type and volume of traffic
anticipated, it is recormended that a minimum pavement thickness of
seven (7) inches be provided.. The pavement should consist of five (5)
inches of well graded gravel base course overlain by two (2) inches of
asphaltic concrete. This is recmneaded provided that the subgra4e is
prepared in accordance with the #Site.Grading" section of this report.
GENERAL RECUMDATIQHS
(1) laboratory tests indicate that crater soluble sulfates in the
soil are negligible,, -and a Type I cement may be used in all
concrete exposed to subsoils. All slabs on. grade subjected to
de-icing chemicals should be composed of a more durable
concrete using a Type ii cement with low dater -cement ratios
and higher air contents.
(2) Finished grade should be sloped away from the structures on
all sides to give positive drainage. It is'suggested that
five percent (5%) for the first ten (10) feet away from the
structures be provided.
(S) 8ackfill around the outside perimeter of the structures should
be mechanically compacted at optimum moisture to at least
ninety percent (90,00) of Standard Proctor Density ASTM D 698-
70. (See Appendix C.) Puddling should not be permitted as a
method of compaction.
(4) All plumfbing and utility trenches underlying slabs and paved
areas should be backfilled with an approved material compacted
to at least ninety-five percent (95%) of Standard Proctor
Density AS7M D 698-70. Puddling should not be permitted as a
method of compaction.
(5) Gutters and downspouts should be designed to carry roof runoff
water well beyond the backfill area..
(6) Underground sprinkling system should not be installed within
ten (10) feet of the structures, and this recommendation
should be taken into account in the landscape planning.
(7) Plumbing under slabs should be eliminated wherever possible
since plumbing failures are quite freque,ntlly the source of
free water which cause slab movement,
(8) Footing sixes should be proportioned to equalize the unit
loads applied to the soil and thus minimize differential
settlements.
i
(9) It is recramiaended that all compaction requirements specified
herein be verified in the field with density tests performed
under the direction of the geotechnical engineer,
.00) It is recommended that a registered professional engineer
design the foundations using the recemmendations presented in
this report.
GENERAL CMIMENTS
This report has been prepared to aid in.the evaluation of the
property and to assist the architect and/or engineer in the design of
this project. In the event that any changes in the design of the
structures or their locations are planned, the conclusions and recom-
mendations contained in this report will not be considered valid unless
said changes are revievied and.conclusions of this report modified or
approved in writing by Empire Laboratories, inc., the soils engineer of
record.
Every effort was rude to provide comprehensive site coverage
through careful locations of the test borings, while keeping.the site
investigation economically feasible. Variations in soil and groundwater
conditions between test borings may be encountered during construction.
In order to permit correlation between the reported subsurface"con-
ditions and the actual conditions encountered during construction} and
to aid in carrying out the plans and specifications as originally
contemplated, it is recommended that Empire Laboratories, Inc. be
retained to perform continuous construction review during the excavation
and foundation phases of the work. Empire Laboratories, Inc. assumes no
.responsibility for compliance with the recondations included in this,
report unless they have been retained to perform adequate on -site con-
struction review during the course of construction.
MUM
No Text
A-2
EMPIRE LABORATORIES. INC.
• 4
• ® KEY TO BORING LOGS
TOPSOIL
�•��
GRAVEL
®
FILL
�:
SAND & GRAVEL
7
SILT
77
SILTY SAND & GRAVEL
CLAYEY SILT
d�a
0
COBBLES
�i.
SANDY SILT
SAND, GRAVEL &COBBLES
®
CLAY
WEATHERED BEDROCK
SILTY CLAY
PH
SILTSTONE BEDROCK
SANDY CLAY
CLAYSTONE BEDROCK
1 '-
SAND
17-1
SANDSTONE BEDROCK
'•��
i.
SILTY SAND
LIMESTONE
CLAYEY SAND
"'" "
K x
xxx
GRANITE J
F7--,"l'
SANDY SILTY CLAY
SHELBY TUBE SAMPLE
STANDARD PENETRATION
1
DRIVE SAMPLER
WATER TABLE 48 HOURS
AFTER DRILLING
HOLE CAVED
5/12 Indicates that 5 blows of a 140 pound
hammer falling 30 inches was required to penetrate 12 inches.
A-3
EMPIRE LABORATORIES,
INC..
. 95
LOG OF BORINGS
TBM, top of curb west side of existing drive. Assume elevation =
.100.0'. -
A-4
EMPIRE LABORATORIES, INC.
100
95
.N
No Text
CONSOLIDATION --SWELL TEST
BORING NO.? „ DEPTH 3.0
.78 90.3 r/Ft3
DRY DENSITY
% MOISTURE 16.3
.77
:. 76 1 NJ
O .75
o .74
.73
72
0.1 0;5 1.0 5 10
APPLIED PRESSURE—TONS/SQ. FT.
z 2
O
Q
0 3
a
O
u 4
0.5 1.0 5 10:
APPLIED PRESSURE--TONS/SQ. FT.
B-2
EMPIRE LABORATORIES, INC. _
Av
CONSOLIDATION --SWELL TEST
.68
0.67.
a
0.66
W
m G
I
N
LO
0
M
ter
1=
O
t.0
W<
o
¢�
o
N
J
w
N
V
N
W
N
LU Li.
Z
F—
p a
"'
N
W
U m
O
CD
O
O
O
O
�..
p0
co
M
r
00Lu
m
M
Z W
r
Cflr
Q
LL
N
r
N
rCie
O
Z
o"
o cn
-
rn
DC
Z
.
-
uj
N
}
N
Z ei
Cl
U7
M
01
CV
I�
'
O C!
cY
1-_
CD
O
0
w
a'
D
N
N
cf
p N
Si
In
N
N
CI
lfl
1_:
C")
i
0
r
r
N
N
N
r
r
N
N
C\I
r—
N
N
CAI
I
,
O
O
O
O
0
0
O
O
O
O
O
O
r
r
Jr
LO
W
M
to
Co
ON.
Gt
UY
CO
01
W �y,,,
1
1
1
1
I
1
1
1
1
I
1
1
1
1
�
O
O
O
O
�
O.
O
O
O
U)
Cl)
CID
O
Uy
M
-::p
I,,
00
C`
m
CF
1-�
CX
co,
M
CT'
1,—
w
M
c�
Z, O
N
Z
r
M
O
II
t0
ZW
o=
Q Z N N N N N N. N CV Cal N (NJ N
Cierr_ r r r r e-- r r r• r r
w
N
Z r Gr to N M t� l0 Gt lC> M
w0 -
rL m
w
°
I ca IJul
-
tnW
- -
^.
- --
a Q
C> .
W tL
C>
N
Iw
::3
U
L� J
w LL
Z
CC
a H
w
N
V
W
F-
0�
O
O
O
O
O
O
p
0
Z w
r
CO
Cfl
LC>
r
^
Cn'
O
�
N
ti
LO
L[>
C>
<
Q
0
LL
M
C�
Q N
m
-
J
Z
_
Q
LU
.4J
N
>-
Wu:
Li
N
d`
ON
a—
Cll
to
N
0 a
p
14;
r
Lfy
m
r
ch
r
dl
011
C>
m
OY
dl
00
Cil
0
r
W
r'
OC)
r
r
00
M
to
CAI
O
m
LLi
�
m
r
ON
N
Lr;
r
CS1
r
r
N
N
N
r
r-
N
N
N
r-
r
CII
N
l!
O
O
O
O
O
O
O
O
O
C>
CD
O.
O
0
0
C>
LL
Gt
LO
00
CSl
r
d'
L!7
CO
Cil
r
-Ad-
LO
M
m
r-
d-
LS)
CO
M
r•
w
UJ
1
1
1
I
1
1
1
1
1
t
1
1
1
1
I
1
1
1
1
O
O
O
O
LO
C>
O
C>
CD
LO
O
C>
CD
O'
Lfi
O
O
O
O
Lo1
M.
d'
tl
00
M
M
ct'
Ih
00
M
M
t-'
CO
M
C`
n
C 6
M
ZD
o z. C , LO
Co
Q G
Atterberg Summary
Boring Number
2
6 .
Depth (Ft..)
3.0-4.0
3.0-4.0
Liquid Limit
31.0
29.0
Plastic Limit
20.0
23.0
Plasticity Index 11.0
6.0
Passing #200
Sieve 83.8
77.0
Group Index
8.0
8.0
Classification
Unified
CL
ML
AASHTO
A-6(8)
A-4(8)
•.
f,
i
i.
APPENDIX C
Suggested Specifications for Placement of Compacted Earth Fill
and/or Backfills.
G E N E R A L
A soils engineer shall be the owner's representative to inspect and
control. all compacted fill and/or compacted backfill placed on the
project. The soils engineer shall approve all earth materials prior
to their use, the methods of placing, and the degree of compaction
obtained. A verification of approval from the soils engineer will be
required prior to the owner's final acceptance of the filling opera-
tions.
MATERIALS
Soils used for allcompacted fill beneath interior floor slabs shall
be a granular, nonexpansive type. The upper 12" to 18" of compacted
earth backfill placed adjacent to exterior foundation walls shall be
an impervious, nonexpansive material. No material having a maximum
dimension greater than six inches shall be placed in any fill. All
materials proposed for use in compacted fill and/or compacted back -
fill shall be approved prior to their use by the soils engineer.
PREPARATION OF S U B G R A D E
All topsoil, vegetation, debris, and other unsuitable material shall
be removed to a depth satisfactory to the soils engineer before begin-
nine preparation.of the subgrade. The subgrade surface of the area
to be filled shall be scarified a minimum depth. of six inches, mois-
tened as necessary, and compacted in a manner specified below for the
subsequent layers of fill. Fill shall not be placed on frozen or
muddy ground.
C-2
PLACING FILL
No sod, brush, frozen material, or other unsuitable material shall be
placed in the fill. Distribution of material in the fill shall be such
as to preclude the formation of lenses of material differing from the.
surrounding material. The materials shall be delivered to and spread
on.the fill surface in a manner which will result in a uniformly com-
pacted fill... Prior to compacting, each layer shall have a.maximum
thickness of eight inches, and its upper surface shall be approximately
horizontal.
M0I S T U R E _C.0_NT..R0L
While being compacted, the fill material in each layer shall as nearly
as practical contain the amount of moisture required for optimum com-
paction or as specified, and the moisture shall be uniform throughout
the fill. The contractor may be required to add necessary moisture to
the fill material and to uniformly mix the water with the fill material.
if, in the opinion of the soils engineer, it is not possible to obtain
uniform moisture content by adding water on the fill surface. If. in
the opinion of the soils engineer, the material proposed for use in
the compacted fill is too wet to permit adequate compaction, it shall
be dried in an acceptable manner prior to placement and compaction.
COMPACTION
When an acceptable,.uniform moisture content is obtained, each layer
shall be compacted by a method acceptable to the soils engineer and
as specified in the foregoing report 'as. determined by applicable
.standards. Compaction shall be performed by rolling with approved
tamping rollers, pneumatic -tired rollers, three -wheel power rollers,
vibratory compactors.or other approved equipment well -suited to the
soil being compacted. If a sheepfoot roller is used, it shall be
provided with cleaner bars attached in a manner which will prevent
.the accumulation of material between the tamper feet. The rollers
should be designed so that the effective weight can. be increased.
C-3
L
c_a