HomeMy WebLinkAboutAsGradedGeotech(Aug.14,2001)
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Providing Professional Engineering Services Since 1 959
~ SOIL. & TE5,TlNG. INC.
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AS-GRADED
GEOTECHNICAL REPORT
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LOT 270F TRACT 23125, LOT 290F'
TRACT 23125-1 AND LOT 35 OF
TRACT 23125-3 -
STERLING RANCH
, TEMECULA, C~L,IFORNIA
PREPARED FOR:
KB HOME
12235 EL CAMINO REAL, SUITE 100
SAN DIEG'O, CALIFORNIA 92130
PREPARED BY:
SOUTHERN CALIFORNIA SOIL & TESTING, INC.
6280 RIVERDALE STREET
SAN DIEGO, CALlFOR'NIA 92120
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P.O. 80x 600627 '
San Diego, CA 92160-0627
6280 Riverdale Street
San Diego, CA92120
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VI{WW.scst.com .
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TABLE OF CONTENTS
SECTION
PAGE
SITE DESCRIPTION AND PROPOSED DEVELOPMENT...........................................................................1
, SITE PREPARATION ............. ....... .... .... .... .......... ... ..... ......... ............... ........ ............... ..... ...... .......... .... ..... .....2
Clearing and Grubbing...................................................................................................................... .............2
Keyways ... ....... ..... ... .... ........ ... .... ....:...... ....... ... ....,.. .:..... ....... ......... ... ... ... ......... .... ..... ........................ .... ..........2
Fill Slopes......................................................................................................................... .............................2
Unsuitable Soil Removal. .................. .................... ............... .................. .... ..... ..... .... .... ... .......................:........2
Fill Placement. ......... ... ........ ....... ............ .... ... ................. ....... ............... ........ ..... ........ .... .................... .......:.....2
FIELD OBSERVATION AND TESTING ............ ........... ...................... ............. ........ ......................................3
LABORATORY TESTS .. ..... ... ........... .... .... .... ............ ....... ............................. ...... ... .... ... ........................... .....3
, REMAIN ING WORK ... ... ........ .... ................... ................. ....... ....... ................ ..... .............................................3
CONCLUSIONS ........... .......,................................................ ...:. ........ ...... ......... .... .... ........;........................ .....4
FOUNDATIONS ....... .............. ........... ................ .................... ............. ...........................................................4
General...........................................:.............................................................................. ................................4
Reinforcement................... .'...:.......................................................................................................................4
Foundation Excavation Observation..................................................................................................,............4
~~~~n~~~t~~~~~;';:i~~i~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::~
ON-GRADE-SLABS.... ... ..... ....... ............... .... ... .:........ ................ ..... ...... ........ .................................................5
I nterior Concrete Slab-on-Grade .........................:...................................;..................................................... 5
LI MIT A TIONS ..... ..................... ....... ................... ... ............................ .....: ......... .... ............... ... ..... ................ ...5
ATTACHMENTS
PLATES
prate 1
Plate 2-3 '
Site Plan
In-Place Density Test Results
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jl( SOil & TESTING, INC.
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PH 0 N E
(619) 280-4321
P.O. 80x 600627
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San Diego, CA 92160.0627
6280 Riverdale Street
San Diego, CA 92120
WWW.scst.com
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TO L L F R E E
(877) 2154321
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(619) 280-4717.
August 14, 2001
SCS&T 0111142
Report No.1
,
Mr. Craig Stinger .
KB Home
,
12235 EI Camino Real, Suite 100
San DiegCl, California 92130
Subject:
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AS-GRADED GEOTECHNICAL REPORT
STERLING RANCH
LOT 27 OF TRACT 23125, LOT 2!:! OF TRACT 23125-1
AND LOT 35 OF-TRACT 23125-3
TEMEGULA, CALIFORNIA
Reference:
1) "Summary of As-Built Geology, Field Observations ,and Tests for Relative
Compaction, Tracts 23125, 23125-1, 23125-2. and, 23125-3, 'Sterling Ranch,
Temecula, Califomia;" Southern California Soil and Testing, Inc.,#9411105.14;
December 8, 1994.
2) "Updated Geoteqhnicallnvestigation, Sterling Ranch, Tentative Tract'23,125,
Temecula, Califomia;" Southern.California Soil and Testing, Inc., #9411105.1; June
21, 1994. .
Dear Mr. Stinger:
In accordance with your request, this report has been prepared to present the resultsof'.field
observations and,testing performed in conjunction with the recent grading operations at the subject
site. Our services were performed betWeen June 27, and July 31,2001. .
SITE DESCRIPTION AND PROPOSED DEVELOPMENT.
The project sife consists of Lots 27, 29.and 35 of County of Riverside Tracts 23125,23125-1 and
23125-3, respectively, in the City of1 Temecula. California. Mass grading for the tracts was
performed in 1994 (se.e Reference 1). However, the subject'lots were.not developed at that time. .
because they werE." being utilized as emergency access roads as required by the City of Temecula.
Completion of development on adjacent properties subsequently eliminated the need for the
emergency access roads and made the lots available for residenti~1 development The recent
grading operations consisted of removing the improvements associated with the emergency access
roads. including two keystone walls on Lot 35, and filling or cutting to restore the building pads and
slopes to their original massgr,!ded condition: The proposed development will consist of one- and
,two-story, single-family residences utiliz,ing shallow foundations and. wood frame construction.
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Sterling Ranch, Lots 27, 29 and 35
SCS&T No. 0111142-1
August 14, 2001
Page 2
SITE PREPARATION
Clearing'and Grubbing
Site preparation began with the clearing and grubbing of the existing vegetation and organic.'
matter from the proposed development areas. Two Keystone walls were removed from the
areas adjacent to the northern and southern property lines of Lot 35. ThetJelow-grade geogrids
associated with these walls were removed from the building pad and rear yard areas of Lot 35,
but were left in place beneath the gently sloping open space area in the western portion of the
lot. The detrimental material generated from these operations was exported from the site.
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Keyways
To provide support for the fill slopes at Lots 27 and 29, keyways were cut into compacte,d fill
soils and/or competent Pauba Formation deposits at the toes of the slopes. The keyways were
generally about 15 feet wide and Sloped back into the existing sloping terrain at an approximate
gradient of two percent. The keyway bottoms were scarified to a depth of 12 inches, moisture
conditioned and compacted prior to receiving additional fill. In accordance with our
recommendations, temporary and natural slopes steeper than an inclination of 5:1 (horizontal to
vertical) were benched. The approximate locations and bottom elevations associated with the,
keyways are depicted on Plate Number 1.
Fill Slopes
Fill slopes were constructed on Lots 27 and 29. The fill slopes were over-filled and cut back to
designed irrclinatiDns. In order to provide for a uniformly compacted slope surface, the slopes
faces were track-walked with a Caterpillar D6 bulldozer. The upper portion of,the slope on Lot
27 remains to be filled, trimmed back and track-walked.
Unsuitable Soil Removal
L?oseor stockpiled soils within the emergency access road reconstruction areas were removed.
or benched into undisturbed ground as grading progressed. Loose or disturbed soils within the .
Keystone wall foundation areas were removed prior to placement of backfill soils. These
removals typically extended to 3 to 4 feet below adjacent grades. The building pad areas of Lots
29 and 35 were excavated to depths of approximately 2 feet and 1 foot below house pad level,
respectively, due to the presence of loose surficial soils. Loose surficial soils on the pad surface
of Lot 29 were found to be minimal. The pad surface of Lot 29 was scarified, moisture
conditioned and compacted to at least 90 percent relative compaction.
Fill Placement
Areas to receive fill were scarified to a depth of 12 inches, moisture conditioned and compacted
until field density tests indicated a minimum of gO percent relative compaction determined in
accordance with ASTM D 1557-91. The soils generated from the removal operations, on-site
cuts, and imported soils were placed in the removal areas as uniformly compacted fill. TypicallY:'l
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Sterling Ranch, Lots 27, 29 and 35
SCS&T No. 0111142-1
August 14, 2001
Page 3
fill soils were placed in thin, moisture conditioned lifts and compacted until field density tests
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indicated a minimum of 90 percent relative compaction. Compaction was achieved with a
Komatsu W A250 and W A380 rubber tire loaders. This process. continued until 'design'
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elevations were reached. The rear yards of Lots 27 and 29 are currently approximately 1 to 4
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feet below proposed finish grade. It is our understanding that these areas will be brought to
grade with compacted fill derived from footing excavations and 'other sources at a later time.
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FIELD OBSERVATION AND TESTING
Field observations and density tests were performed by'a representative of Southem California Soil
and T~sting, Inc., during the grading operations in accordance with ASTM D 2922-91 (nuclear
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gauge) procedures. Test locations are shown on Plate Number 1, while test results are summarized
on Plates Number 2 and 3. The accuracy of the in-situ density test locations and elevations is a
function of the accuracy of the survey control provided by other than Southern California Soil and
Testing, Inc. representatives. Unless otherwise noted, their locations and elevations were
determined by pacing and hand level methods and should tie cons,idered. accurate only to the'
degree implied by the method used.
As used herein, the term "observation" implies only that we observed the progress of work we were
involved with, a~d performed field density tests, which in conjunction with our observations, were the
basis for our opinion as to whether the work was performed in substantial conformance with the
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. geotechnical recommendations and the requirements of the applicable agencies.
LABORATORY TESTS
Maximum dry density determinations were performed on representative samples of the soils used in
the compacted fills according to ASTM D 1557-91, Procedure A and C. Procedure A is used when
the soil contains 20% or less by weight of material retained on the #4 sieve. This procedure
. specifies that a 4-inch diameter cylindri~al mold of 1/30 cubic foot volume be used and that the soil
tested be placed in 5 equal layers with each lilyer compacted by 25 blows utilizing a 10-pound
hammer with an 18-inch drop. Procedure C is u~ed when.the soil contains more than 20% by
weight of material is retained on the 3/8" si~ve and less th~n 30% by weighUs retained on the 3/4"
sieve. This procedure specifies that a 6- inch diameter cylindrical mold of 1/13 cubic foot volume be
used and that the soil tested be placed in 5 equal layers with each layer compacted by 56 blows
utilizing a 10-pound hammer with an 18.-inch drop. The results of these tests', presented on Plate
Number 3, were used in conjunction with the field density tests to determine the degree of relative'
compaction of the compacted filL
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REMAINING WORK
The following operations remain to be completed. It is recommended that field observations and
relative compaction tests be performed during these operations to verify that these operations are
being performed in accordance with job requirements and local grading ordinances.
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Sterling Ranch, Lots 27, 29 and 35
SCS&T No. 0111142-1
August 14, 2001
Page 4
. Final grading of the rear yards of Lot 27 and 29;
. Final grading of driveways and hardscape areas;
. Final grading of the upper'pDrtion of the slope at,Lot 27;
. Backfilling of underground utility trenches.
CONCLUSIONS
Based on our field observations and in-place density test results, it is the opinion of Southern
California Soil and Testing, Inc. that the grading work was performed substantially in accordance
with the recommendations contained in the referenced geotechnical reports, the City of Temecula
Grading Ordinance, and the Uniform Building Code. Minimum recommendations for the design of
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foundations are summarized below.
FOUNDATIONS
General
Shallow foundations may be utilized for the support of the proposed structure. The footings
should have a minimum depth of 24 inches. below the lowest adjacent finish pad grade. A
minimum width of 12 inches and 24 inches is recommended for continuous and isolated
footings, respectively. A bearing capacity of 2000, pounds per square foot (psf) may be .
assumed for said footings. ,This bearing capacity may be increased by one-third when
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considering wind and seismic forces. Footings located adjacent to or within slopes should be
extended to a depth such that a minimum distance of seven feet exists between the bottom of
the footing and the face of the slope. Retaining walls in similar conditions should be extended to
a depth such that a minimum distance of ten feet exists between the bottom of the fooling and
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the face of the slope.
Reinforcement
Footings should be reinforced wi~h at' least two NO.5 bars positioned near the bottom of the
footing and at least two NO.5 bars positioned near the top of the footing. This reinforcement is
based on soil characteristics and is not intended to be in lieu of reinforcement necessary to
satisfy structural considerations.
Foundation Excavation Observation
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All footing excavations should be observed by a member of our engineering/geology staff prior
to the placement of forms or reinforcing steel to verify that the foundation excavations extend
into a suitable bearing stratum.
. Expansion Characteristics
The prevailing foundation soils were found to, be non-detrimentally expansive.
recommendations contained in this report are applicable to this condition.
The
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Sterling Ranch, Lots 27, 29 and 35
SCS&T No. 0111142-1
. August 14, 2001
Page 5
Settlement Characteristics
The anticipated total and/or differential settlements for the proposed structures may be
considered to be within tolerable limits, provided the recommendations presented in this report
are followed. It should be recognized that minor cracks normally occur in concrete slabs and
. foundations due to shrinkage during curing or redistribu)ion of stresses, and some cracks should
be anticipated. Such cracks are not necessarily an indication of excessive movement.
ON-GRADE-SLABS
Interior Concrete Slab-on-Grade
Concrete floor slabs should have a thickness of at least four inches and should be reinforced
with at least No. 4 reinforCing bars placed at 18 inches on center each way. The slab
reinforcement should be placed approximately at the middle of the 'slab. The slab should be
underlain by a four-inch blanket of clean, poorly graded, coarse .sand or crushed rock. This
blanket should consist of 100 percent material passing the one-half inch screen and no more
than ten percent and five percent passing sieves #1 00 and #200, respectively. Where moisture
sensitive floor coverings are planned, a ten-mi(visqueen barrier should be placed over the sand
layer. To allow for proper concrete curing, the visque'en should be overlain by an additional two.
inches of sand.
LIMITATIONS
This report covers .only the services performed between June 27, and July 31,2001. 'Our opinions
. presented herein are based on our observations and the relative compaction test results and are
'limited by the scope of the services, which we agreed to perform. Our services were performed in
accordance with the currently accepted standard of practice and in such a manner as to provide a
reasonable measure of the compliance of the grading operations with the job requirements. No,
warranty, express or implied. is given or intended with respect to the services which we have
performed, and. neither the performance of those services nor the submittal of this report should be
construed as relieving the contractor of his responsibility to conform with the job requirements.
Our services were generally performed on an "on-call" basis. Therefore, the in-place density tests
performed by our field representative can only be construed as representative of the areas tested
which are shown on the attached plates.
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Sterling Ranch, Lots 27, 29 and 35
SCS&T No. 0111142-1
August 14, 2001
Page 6
Should you have any questions regarding the contents of this report, Dr if we may be of further
assistance, please contact our office at your convenience.
Respectfully submitted,
~OUTHERN CALIFORNIA SOIL AND TESTING, INC,
MF:DSA:mf
(4) Addressee
(1) City of Temecula
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I JOB NAME: Sterling Ranch JOB NUMBER: 0111142
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I TEST ELEVATION MOISTURE DRY DENSITY SOIL REL.COMP,
NO, DATE LOCATION (feet,MSL) (percent) (p,c.f.) TYPE (percent)
I 1 7/2/01 Lot 27135, keyway 1205.0 12.3 116.S 1 92.1
2 7/2/01 Lot 27135, keyway 1206.0 12.5 115.7 1 91.5
3 712101 Lot 27/35, keyway 1208.0 10.7 118.6 1 93.8
I 4 712101 West of keyway 1209.0 11.3 119.2 1 94.2
5 7/3/01 Lot 27 1211.0 13.6 115.6 1 91.4
6 7/3/01 Lot 27 1213.0 12.1 119.5 1 94.5
I 7 7/3/01 Lot 27 1215.0 13.5 116.6 1 92.2
8 7/3/01 Lot 27 1216.0 11.2 117.1 1 92.6
g 7/5/01 Lot 27 1218.0 10.6 119.0 1 94.1
10 7/5/01 Lot 27 1220.0 9.3 115.2 1 91.1
. 11 7/5/01 Lot 27 1221.5 12.3 119.2 1 94.2
12 7/5/01 Lot 27 1223.0 13.3 119.0 1 94.1
13 7/6/01 Lot 27 1225.0 10.2 115.8 1 91.5
I 14 7/6/01 Lot 27 1226.5 9.2 118.1 1 93.4
15 7/6/01 Lot 27 1227.0 13.2 115.3 1 91.1
16 7/6/01 Lot 27 1228.0 12.5 118.4 1 93.6
I 17 7/9/01 Keyway, Lot 29, Via Alvaro/Calle Morita 1184.0 11.7 113.8 1 90.0
18 7/9/01 Lot 29, Via Alvaro/Calle Morita 1186,0 12.1 116.3 1 91.9
19 7/9/01 Lot 29, Via Alvaro/Calle Morita 1187.0 11.1 116.8 1 92.3
. 20 7/9/01 Lot 29, Via Alvaro/Calle Morita 1188.0 11.7 115.5 1 91.3
21. 7/10101 Lot 29, Via Alvaro/Calle Morita 1190.0 11.2 116.5 1 92.1
22 7/10/01 Lot 29, Via Alvaro/Calle Morita 1191.0 9.5 116.0 1 91.7
23 7/17/01 Lot 27, Via Sabino 1229.0 11.3 113.8 1 90.0
I 24 7117101 Lot 27, Via Sabino 1230.0 11.7 119.7 2 90.9
25 7/17/01 Lot 27, Via Sabino 1232.0 10.3 116.8 1 92.3
26 7/17/01 Lot 27, Via Sabino 1233.0 9.5 116.0 1 g1.7
I 27 7/18/01 Lot 27 1233.5 g.O 120.2 1 95.0
28 7/18/01 Lot 27 1234.0 10.6 118.7 1 93.8
29 7/18/01 Lot 27 1234.0 11.2 119.5 1 94.5
I 30 7/19/01 Lot 29 1189.0 11.6 128.7 3 96.7
31 7/19/01 Lot 29 1189.0 10.1 120.0 3 90.2
32 7/19/01 Lot 29 1189.0 11.0 121.1 3 91.0
33 7/19/01 Lot29 1189.0 10.6 120.7 3 90.7
I 34 7/23/01 Lot 29 1191.0 8.9 122.3 3 91.9
35 7/23/01 Lot 29 1191.0 7.7 123.6 3 92.9
36 7/23101 Lot 29 1191.0 8.2 124.1 3 93.2
I 37 7/25/01 Lot 35 1180.5 10.7 124.0 3 93.2
38 7/25/01 Lot 35 1180.5 8.5 121.6 3 91.4
39 7/25/01 Lot 35 1180.5 9.1 125.9 3 94.6
. 40 7/25/01 Lot 35 1184.0 10.2 124.7 3 93.7
41 7/25/01 Lot 35 1186.0 g.O 122.2 3 91.8
42 7/25/01 Lot 35 1190,5 8.8 123.8 3 93.0
I 43 7/25/01 Lot 35 1192.0 9.2 125.5 3 94.3
44 7/27/01 Finish Pad Grade for Pad 35 1181.0 11.5 124.6 3 93.6
45 7/27/01 Finish Pad Grade for Pad 35 1181.0 10.1 126.2 3 94.8
46 7/27/01 Finish Pad Grade for Pad 35 1181.0 9.8 125.3 3 94.1
I 47 7/27/01 Finish Pad Grade for Pad 29 1182.0 10.7 123.0 3 92.4
48 7/27/01 Finish Pad Grade for Pad 29 1182.0 11.6 126.3 3 94.9
49 7/27/01 Finish Pad Grade for Pad 29 1182.0 10.0 125.1 3 94.0
I PLATE NO.2 ~
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JOB NAME:
Sterling Ranch
JOB NUMBER:
0111142
TEST ELEVATION MOISTURE DRY DENSITY SOIL REL.COMP.
NO. DATE LOCATION (feet,MSL) (percent) (p.c.f,) TYPE (percent)
50 7/30101 Finish Pad Grade for Pad 27 1236.0 8.6 122.1 3 91.7
51 7/30101 Finish Pad Grade for Pad 27 1238.0 9.7 125.7 3 94.4
52 7/30101 Finish Pad Grade for Pad 27 1238.0 9.0 124.0 3 93.2
Soil
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MAXIMUM DENSITY AND OPTIMUM MOISTURE SUMMARY (ASTM D1557)
Maximum
Densitv. pcf
126.5
131.7
133.1
Soil Description
Brown, Silty Sand with gravel
Brown, Silty Sand with gravel
Brown, Clayey Sand
Optimum
Moisture. %
8.8
8.0
7.1
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PLATE NO.3