HomeMy WebLinkAboutCT 02-28; La Costa Condominiums; Soils Analysis after Powers/Banich Slope Repair; 2009-03-11IERNAIE LANDSLIDE: .
MMENDATION
.A COSTA
CONDOMINIUMS 3
jl 1,2009
EN. 23280.10
Corporate Office: 5764 Pacific Center Blvd.
22725 Old Canal Rd. Suite 112
Yorba Linda, CA 92887 San Diego, CA92121
American
Geotechnical Inc.
5600 Spring Mtn. Rd. 10398 Rockingnam Dr.
Suite 201 Suite 7
Las Vegas, NV 89146 Sacramento, CA 95827
SOIL, WUNDAi ION & UfcOLOGIC STUDIES
American Geotechnical, Inc.
SOIL, FOUNDATION AND GEOLOGIC STUDIES
March 11, 2009 File No. 23280.10
Mr. Kwan So
LA COSTA VISTA LLC
2683 Costebelle Drive
La Jolla, California 92037
Subject:
RECEIVED
MAR 16 2009
ENGINEERING
DEPARTMENT
Reference:
ALTERNATE LANDSLIDE REMEDIAL RECOMMENDATIONS
PROPOSED LA COSTA CONDOMINIUMS
Lot 185, La Costa Avenue South - Unit 1
Carlsbad Tract No. 02-28
Carlsbad, California
"Recommended Remedial Grading Procedures, La Costa Condominiums, Lot 185 of La Costa
South Unit 1, Carlsbad Tract No. 02-28, Carlsbad, California", prepared by American
Geotechnical, dated May 31, 2007.
"Revised Updated Geotechnical Report, Proposed La Costa Condominiums, Lot 185, La
Costa Avenue South - Unit 1, Carlsbad Tract No. 02-28, Carlsbad, California", prepared by
American Geotechnical, dated February 14, 2008.
Dear Mr. So:
Following our meeting on September 24, 2008, American Geotechnical is pleased to present alternate landslide
remedial recommendations for the subject development as discussed during the meeting. The following
information is contained in the report:
• Alternate Landslide Remediation Plan and details including cross sections and tie back anchor block
(Plate 1 through 5)
• Tie back anchor block design calculations
• Slope stability analysis
We appreciate the opportunity to be of service. If you should have any questions, please do not hesitate to
contact us.
Sincerely,
AMERICAN GEOTECHNICAL
Guillaume Gau
Project Engineer
R.C.E. 70015
Via Mail Only
Via Mail Only
Via Mail Only
Edred T. Marsh
Principal Engineer
G.E. 2387
ETM/GG: kb
Distribution:Mr. Kwan So-(1)
Mr. GregLinhoff-(l)
Mr. John Strohminger - (1)
22725 Old Canal Road, Yorba Linda, CA 92887 - (714) 685-3900 - FAX (714) 685-3909
5764 Pacific Center Blvd., Suite 112, San Diego, CA 92121 (858) 450-4040 - FAX (858) 457-0814
10398 Rockingham Drive, Suite 7, Sacramento, CA 95827 (916) 368-2088 FAX (916) 368-2188
5600 Spring Mountain Road, Suite 201, Las Vegas, NV 89146 - (702) 562-5046 - FAX (702) 562-2457
SLOPE STABILIZATION USING TIEBACKS
File Number:
File Name:
23280.02
La Costa
I. - Tieback Load - 36 k/ft
DESIGN CRITERIA
Tieback load per foot =
Tieback Spacing, s =
Service Load per Tieback, P =
CHECK BEARING PRESSURE
Allowable Bearing Pressure =
Anchor Block Width, \v =
Bearing pressure, a = P (\tf)l[(w)(s)} =
kips/ft
ft on cener
psf
4888.89 psf
ANCHOR BLOCK DESIGN
Check for Wide Beam Shear (One-Way Shear)
352 kips
7.82 ksf
'„ = }.6P =
?,,=/V[("')(*)] =
Size of bearing plate (square), b = | 12] inch
.A = | 4500|psi
psi
d
T
w1
The critical section for wide beam shear occurs at a distance d from the face of the bearing plate.
So shear at critical section
12.00 inch
Vu = [(s 12 -b!2)- d](w )q „ = 88.00 ksf
<t>Vc = [0.85(2)sqrt(/1
cX144)/]Q3](t/)(w) = 123.16 ksf
Used= I 771/nc/i OK
Check for Diagonal Tension (Two-way shear)
/ = b + 2(d/2) =
Perimeter = 4(b+d) =
A = (b+d)2/144 =
Vu = P,, - (A)qu =
26 inch
8.67 ft
4.69 ft2
315.28 kips
•9
d/2y.
Shear stress =
V(aii)= 4 <|» sqrt(fc') =
31.18 kips
228.08 psi =32.84 ksf
Vsed =
Total anchor block thickness =
USE
[OK]
14 |inch thick (effective) anchor block
] 8.5 inch (assume #8 bar both dir.)
20 \inch thickness anchor block
DESIGN FOR REINFORCEMENT
Longitudinal Direction (Long way)
Assume simply supported conditions between tiebacks
and consider
w = Pis 36.666667
M,,= 1.6Mmax =
Mu = <))A/y(d - a/2)
As= 0.6
d- 15.6875
a = A/y/(0.85/cb) =
Mu = ())A/y(d - a/2) =
12 [inch wide section
kips/ft
132 kips-ft
211.2 kips-ft = 28.16
in2 dia. = 0.875
0.78
39.00 kips-ft/ft >
kips-ft/ft
Check #7
28.16 kips-ft/ft
bar
Check for minimum renforcement
As(mjn) = pbd = 0.55 <0.6 [OK]
Use 20 inch thick anchor block
#7 \bars @ 12 inch @ top & bottom
(As = 0.60 in-)
Transverse Direction (Short way)
4.89 kips/ft
Use
Use
/ = w/2 - b/2 =
M — ql II—
Mu = l.6M =
Mu = <j)A/y(d - a/2)
A. = I 0.79|in2
a = A/y/(0.85/cb) =
Mu = <))A/y(d - a/2) =
bars @
bars @
3.25 ft
25.82 kips-ft
41.31 kips-ft/ft
1.03
51.35 kips-ft/ft
inch o.c. at bottom
inch o.c. at top
T
w1
41.31 kips-ft/ft OK
(As =
(As =
0.79 in )
0.20 in2)
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