HomeMy WebLinkAboutCT 82-04; PALOMAR OAKS II; RECOMMENDATIONS FOR TEMPORARY SHORING; 1988-08-10I
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REXmMENDATIOOS FOR TEMPORARY SlDRlN:;
ProPOOED OOX ClLVERr
P.AICMAR OAKS II SUBDIVISICN
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PREPARED FOR:
Birtcher Constru.ction
27822 El Lazo Road
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Laguna Niguel, California 92656-3989
PREPARED BY:
SoutheI:n Califo:rn.ia Soil & Testing, Inc.
Post Office Box 20627
6280 Riverdale Street
San Diego, California 9212.0
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SOUTHERN CALIFORNIA SOIL AND TESTING, INC.
6280 RIVERDALE ST. SAN DIEGO, CALIF. 92120 • TELE 280-4321 • P.O. BOX 20627 SAN DIEGO, CAl.IF. 92.120
6 7 BEN T E R P R I S EST. ESC 0 N 0 I 0 0, CAL. I F. 9 2 0 2 5 • TEL. E 7 4 6 -4 5 4 4
August 10, 1988
Birtcher Construction
27822 El Lazo Road
Laguna Niguel, California 92656-3989
A'ITENTION: Mr. Michael Dixon
SCS&T 8821057
Repc:>rt No. 2-R
SUBJECT: Recormendations for Temporary Shoring, Proposed Box CuLvert;
Palomar oaks II Subdivision, Carlsbad, California.
Gentlem:m:
This report has been prepared to present design criteria for tempbraIY
shoring along the north side of the proposed box culvert at the subject
site. Our recormendations are based on our previous investigations at the
site and on three recent test trenches excavated near the north edge of the
proposed culvert.
The three recent test trenches were excavated to determine what soil
conditions will exist along the alignnent of the proposed culvert and to
locate the SIX;&E conduit that parallels the culvert. The conduit was fund to
be concrete encased with the top south edge located from 3.5 to 5.5 feet
below the sidewalk. The south edge is also located about eight feet
horizontally from the face-of-curb along the street. The close proximity of
this conduit will require shoring for the culvert excavation. On the south
side of the culvert the temporaIY slope can be laid back to eliminate the
need for shoring.
SOUTHERN CALIFORNIA SOIL AND TESTING. INC.
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SCS&T 8821057 August 10, 1988 Page 2
A site plan and cross-sections at the two angle points and the center of the
culvert are presented on Plates Number 1 through 4. The' cross-sections alsp
show the approximate position of the SCG&E conduit. These cro$s-sections
illustrate that shoring will be necessary along the north side of the
culvert as a result of the SCG&E culvert.
The soils exposed in our test trenches ~ generally about four to five
feet of medium dense fill over lightly to moderately cemented sandstones. In
exception, the test trench at the west angle point encountered either a
slopewash material or highly weathered sandstone below the fill. This
material was uncenented and had pockets of friable sands.
Unshored temporary slopes for the excavation for the culvert may be
constructed at a 0.5 to 1.0, horizontal to vertical ratio, with the lower
four feet cut vertical. At the west end where the slopewash was found, the
slope should be cut at a 0.75 to 1.0 ratio.
Shoring consisting of vertical steel H-beam solder beams with treated ~
lagging be~ the beams may be used to shore the north side of the culvert
excavation. An allowable passive pressure of 600 pounds per square foot per
foot of depth may be used in design of the solder l:Jeam eniJec::lnent. This value
should be limited to a maximum value of 8000 pounds per square foot. The
allowable bearing capacity of 10,000 psf may be used for solqer beams
extending a least 10 feet below the bottom of the excavation. The active
pressure for the slope may be assuned. to be equivalent to the pressure
indicated in the following diagrams.
q, : 120 H, ,PSF
H 1 : HEIGHT OF SLOPEABO.VE TOP OF SHORING, FT
H 2 : HEIGHT OF SHORING, FT
q 2 : .21(q,>, PSF/FT
q3 = 2eH2 , PSF/FT
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SCS&T 8821057 August 10, 1988 Page 3
The above diagrams is for a sloping backfill (0.5 to 1) and for a drained
condition. Surcharge loading from the adjacent street and temporary
construction equipment loads should be added to the aforementioned values if
necessary.
If you should have any questions after reviewing this report, please do not
hesitate to contact this office.
This opportunity to be of professional service is sincerely appreCiated.
Respectfully submitted,
SOUI'HERN CALIFORNIA SOIL & TESTING, INC.
~lI'a"t;;.
Charles H. Christian, R.G.E. #00215
CHC:m.v
cc: (6) Submitted
(1) SCS&T, Escondido
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PALOMAR OAKS ROAD
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LEGEND
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~ SOUTHERN CALIFORNIA ~ SOIL & TESTING,INC.
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SCALE 1" =20'
o 10 20 30 40
Proposed Box Culvert
BY: DBA DAT£: 8-11-88
JOB NUMBER: 882105.7 Plate No. 1
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