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August 31, 2005
W.O.266704
Newport Beach California
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eotechnical Engineering;nvestiovat�on for Proposed Semi -Subterranean
�� oESeo"otis°�E��t� andEluest House at 4824 Cortland Drive, Corona del Mar, California; by
W.O. 266704, dated December 30, 2004.
- �otist ate Y? o or Proposed Serni-Subterranean Garage, Pool and Guest
FEQooc`o� I use _ g Drive, Corona del Mar, California; by COAST
66704, dated March 29, 2005.
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I d ewith are the responses to the City of Newport Beach Geotechnical Review Sheet,
M 18, 2005. For clarity, each remark is repeated prior to our response.
Page 7. Shoring: Please clarify the difference between EFP = 60 pcf for permanent shoring wall
and basement wail (P.9) and 40 and 55 pcf (P.9) for retaining wall. Please specify the backfill type
for corresponding fluid pressure. Note that for basement walls non -expansive soil is specified
rC' while for retaining wall on -site soil is allowed.
Fes" V Response No. 1:
2
®� The reviewer has misread the recommendations of page 9, Paragraph one indicates that
"basement" walls are recommended to be designed for an EFP of 60 pcf Paragraph five
recommends that "Freestanding' retaining walls may be designed for an EFP of 40 pcf with level
backfill and 55 pcf for 2:1 (E1:V) sloping backfill condition. All wall backfill shall be non -
expansive. The excavation of the rear slope will encounter non -expansive soils, provided the soil is
approved by this office the select soil and may be used as backfill.
COAST GEOTECHNICAL, INC.
Mr. Pouliet 2 W.O.266704
Reply to City Review Sheet Augur 31 2005
emark No. 2:
Page 7, Construction cuts: Please review grading plans and provide shoring recommendations
where bottom of proposed construction cuts are below a 1:1 plane of adjacent site improvements.
Response No. 2:
In accordance with structural plans by Glenn N. Almquist dated May 2, 2005 a permanent shoring
/shotcrete pile wall is planned for the guesthouse and pool area, which will be installed into the
rear -ascending slope. Shoring recommendations are provided on page 7. The guesthouse shall be
structurally separate from the shoring/shotcrete wall in order to use conventional foundations
deriving support from competent native terrace deposit material. Some remedial grading may be
necessary for concrete slab support. As an alternate, a grade beam and pile foundation system may
be used for the guesthouse and incorporated into the foundation of the shotcrete wall.
The pool excavation is expected to encounter bedrock, which will require that all of the pool and
spa shell derive support for bedrock using deepened footing as needed.
Shoring is not required for the semi -subterranean garage. The garage will be excavated four to five
feet below grade and the northerly side yard setback is six feet. The excavation in this area is
expected to encounter dense soil conditions and shallow bedrock, which may be cut near vertical
for three feet then laid back at a 1:1 (H:V).
✓ Remark No. 3-
Please show bottom of proposed structures with their proposed foundations on Plates 2 and 3.
Response No. 3:
The grading plan and cross section are attached.
zRemark No. 4:
Page 11, Floor Slabs: Basement floor slab will be underlain by diatomaceous siltstone at a
relatively shallow depth. Please provide expansion index test for bedrock and present appropriate
slab recommendations based on 97 UBC.
Response No. 4:
The bedrock has a moderate expansion potential with a low plasticity index. Please see attached
calculations of the effective plasticity index. The concrete slab recommendation of our report is
considered germane.
COAS3T GEOTECHNTCnL, INC
Mr. Pouliet 3 W.0. 266704
Reo:v to City Review Sheet August 31 2005
Zm:, kNo.5:
Pape 10, Basement Walls: Please provide slope repair and stabilization measures to bring the
surficial F.O.S. to 1.5 (for remaining slope areas).
Response No. 5:
The entire slope will be excavated to install the guesthouse and pool, the new walls will retain
the small section of the remaining slope above. Any loose surficial soil above the proposed wall
shall be compacted to 90% relative compacted at a maximum 2:1 (H:V) slope gradient.
We appreciate this opportunity to be of service to you.
Respectfully submitted:
COAST GEOTECHNICAL, INC.
Ming-Tarng Chen Todd D. Houseal Daniel E. Here
RCE 54011 CEG 1914 Exp. 4/06 Staff Geologist
Z J TOODA HOIIL N
No.54011-31-
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GEOLOGIC CROSS SECTION
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COAST GEOTECHNICAL
W.O. 266704 Plate 4
EFFECTIVE PLASTICITY INDEX
The following calculation represents the weighted plasticity index and effective
plasticity index for the subject site in accordance with 1997 UBC.
Factor
Depth
F x D
Plasticity Index
F x D x P.I.
3
5
15
15
225.0
2
5
10
15
150.0
1
5
5
15
75.0
Total 30 450.0
Co=1
Cs=1
Weighted Plasticity Index = 450 / 30 = 15
Effective Plasticity Index = 15 " Cc ` Cs = 15 Use 15
Reply to Review Sheet
4824 Courtland
Corona del Mar, California
Work Order 266704
Plate No. P
COAST GEOTECHN/CAL
01/12/1996 10: 00 949-2528293
HAGAHI ENGINEERING PAGE
01
...
CITY OF NEWPQRTBEA,CH
GEOTECIMCAL REPORT RE..MW- CH$CKLTBT
'
Date Received: May.10; $005
Date cvaipltted;.May is, 2005'
X�etecfSiapoit..Dec3Qy2004'
Pfid kAio: 20(i1
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Cot itltarii: Chi (apotecbntaal
Oar,�ofi.l�Io: T4*n-20Q
Additional. Dtictitusatte Revtcw�d:
�
1j Grading Flan :. f�G�i�
Appitoant Nome
k
Site Ad$ress: 4824 Cmrtiead Iitive .
�' � S
LafATractNo,;
Title ofRep6rt G >logio snd.GeoteePtttical'Bnginwring
lnvestlgation ,•
iE}. G
Purpose of Report Foundation R=mitendations
1'rojeet Iaforloi XWWBAdgreuad:
`'� ...
Y Rtview of 8xtsting City F0%
-
Y Refcrence.ta Site {s} by Street Address
..
N Refacence to Gradingfpbua3atian plans by Date
Y SubsurEaae7nvegtition
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N Aerial Photograph
C
Goologie'Ifaza.rdH:-
s
USIA
1i:3613631015;
Adverse Geaiogia Stia
ruvture
y
HliiffRetreat
NA
DebrWMlid.Flow
NA -
I3iffereait;al Setttom�riF
y
Erosion
N
Expansive Soils
N
F
Faulting
y
Fractured Bedrock
NA ..
Groundwater
NA
Landslide
Liquefaction
NA
NA
Settlement/Collapsible Sails _
y
Slump
1
:
SoilMock Cr tp
Sulfate Rich Soils
Y
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39bd 0313OSSV A3ASdO '17I8
V6086SL606 TS:6T S00Z/DZ/80
01/12/1996 10: 00 949-2526293 BAu HI ENGINEERING PAGE e2
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Rerotntraendatibaa fat 8lipparptsg".'
o
:Faunda[rOras' - Y- Slope Stability' Cstetlladons. }?'.
�tetatmng Walls y 311ear Strength Values
. Y
romidafion Setbacks y Other La"tot'y f}aii y
ram:
Sia6s' Ir . Seismicity .
Flatwork-
BOnItgiTi'ea6rlt Logs 'Y
-`•
.;
:Oivding .' y _
Poa1s:S Liquefaction Study N A
t_
CaicutatiQns.Stippantn Recammetidations
5lope/BhdY$etbaara'. NA GeoiogicMap and Cross;Sectimts lY
Adegtiaay'for tntonded use Y Drainage Flan id
Not Adversely impacting N
kodkT_APPROVEII
REPORT APPROVED SURIECT To cormixiarls sEj o,Ar.
t WGJ W APi'tii ]L OF THE REPORT, ATTENI) To TFIk ITEM,
S't�l?! �1VVr
P.7:'-Siwrtng� Please clarify the difference betwt:era EFp dti crr.
p' inn aharitig:wad and
haseenend qy"ells: (P,9) and 40 and 55 pcf (P,9).for retaining welt, Aleaszspeci iy rile baeliYlil typ8s for
'
ecraeapending'tTtrd Pre ures::Note that for basetnent walls isL4-expansive wil s:spec-irl while trt
s.;y
_ retaining wall on;site $oil is altowetL
Consi ction cuts. Pleasc review grading plans and provide snoring roe Iommendatlorts" where
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bottom of PeoposOd construetio cuts s below. a 1: Wine; oFsdiaceift sit improvs Tents.
3: Plase show bottom of proposed structures with their proposed foundations on Flares. Z and #,
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4. F.11, Floor slabs. Baseni631 floor slab will be underlain by diatotnaapus s4ltstaae, at a relatively
shallow depth:: Please provide expansion index test for bedrook and present apprepriam siab
reconmwrldatidns based on:97 uBC.
i '...
5. ' Please provide'siope repair and. stabilization measures to-bring'tt burfieial F03 :t,3 1.5 (fib renaain,op,
slope areas).
A(dadoria! Coittrtte ate ao reemme reaa hvd)
itiote to City Staff: Staff should confirm thattha Consultants (C. E.G_ and R C E1G,) .) vo saytie4 the firm
dated'grading, foundatiuntcobstruction and landsca ' lens, t C' C PmB P � uY ok thereby verifying the pram'.
geatechnicai conformane�e witii the Consultant's original ruport and associated'ed<su*.
- lA nthatiolks of Resew:
t}Ur PWIeV' IS intended to dcrterman0 ft'tlae submitted tryort(s) comply with City Codets eral. generally
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aeceptcd geoteehn cal practices w{tbiti the local area, .The scope of our sorviees fbr this third /;arty review
v.
has been limited to a brief site vi3ar and a review of the above refCre)ced report
yq
itysloeu Oray.
ass lied b the C'
supplied Y City of NewpoR Brach. Opintaps pcs9pnted' in this review' ere for City's use only
for
R-,•analknis of reparted data and/or ca]Qations and preparation of atrAndod cordtnictimt or design
:
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