470, Construct new SFR & garage, gr, Studies & Reportsf
• •
KEITH V\W EI LERT
Consulting Engineering Geologist
March 27, 1992
Dr. and Mrs. Marrone
58 Cypress Way
Rolling Hills, CA 90274
By
1\'IAR 8 i9)G?
City Oi t;uiliNBills
SUBJECT: RESPONSE TO WRITTEN COMMENTS PROVIDED BY MEMBER OF
ROLLING HILLS PLANNING COMMISSION
Proposed Residential Development
13 and 17 Southfield
Rolling Hills, CA
REFERENCE: REPORT OF GEOTECHNICAL INVESTIGATION
Proposed Residential Development
13 and 17 Southfield Drive
Rolling Hills, CA
By AGI Geotechnical dated November 22, 1991
Dear Dr. and Mrs. Marrone:
Pursuant to your request, this response to written comments
presented by a member of the Rolling Hills Planning Commission
has been prepared.
One of the comments requests that one of the cross -sections
presented in the AGI report (cross-section A -A') be extended to
include Southfield Drive. This cross-section was not extended to
Southfield Drive because we do not have detailed geologic
information on #13 Southfield in the area of the existing house.
It was not necessary to investigate the existing house with
regard to the proposed development. As such, we have no data
available to extend cross-section A -A' to Southfield. However,
316 Tejon Place c Palos Verdes Estates, CA 90274 c (310) 378-4146
• •
we did provide "regional" cross -sections in the AGI report which
do extend to Southfield Drive. Copies of these, with the
regional map, are attached to this letter.
Another comment in the letter asked the meaning of a paragraph on
page 31 of the AGI report discussing foundation setbacks. This
section of the report refers to the minimum horizontal distance
that should be maintained between the bottom outer edge of any
foundations and essentially the face of a slope (or the contact
between bedrock and surficial soil deposits). See sketch below.
• •
Concern was expressed regarding "missing" plates that are
referred to in the Soils International report dated October 3,
1977. The reason the plates were not included in our report is
because we were never given the plates. It is likely that these
plates are too large to be copied on a "xerox" machine and were
prints that could not be copied on a conventional "blue line"
machine. As such, whoever made copies of the Soils International
report did not copy the plates that came with the original report
(we were not supplied with a copy of the original report but just
with a xerox copy). We called Soils International and asked if
we could get a copy of the report-- they said it is too old and
they no longer have a copy. However, it is our opinion that they
misidentified the breccia as terrace deposits and did not do as
complete of an investigation as AGI performed. As such, we do
not need their data for our analysis.
We hope this information will satisfy the concerns of the
Planning Commission member. If you have any questions regarding
the information presented in this letter, please call our office.
R spectfully subim it d
th W Ehler t
e
Engineering Geologist
SITE PLAN
EXPLAMMIN
MT*® Mcnte "w . 11an
Af = lam"
Br r. Breccia
Estimated Boring Location
Estimated Test Trench Location
Sinice and Dip of -Bedding
A A Crass Section Line
Contact
Scale r : 50'
36°
lg. s
Area of thick colluvium/slopewaash
e67'
27°
.00
Jr
FIGURE 2
J
7
0
approximate area of proposed construction
AVERAGE ORENTATION OF BEDDING
i
AVERAGE ORENTATION OF
FROM 'TRENCHES
\I IV/
BEDDING FROM BORINGS
REGIONAL MAP
approximate scale 1"=100' s
\1*.‘
1 1
i
FIGURE. 5
C
\\
• • • •
C
N N80E
#17 southfieid
8-i
B-2
#13 southfiied
BRECCIA BRECCIA
BEDROCK
Apparent dip of bedrock
S'a i HF(Er-p
REGIONAL CROSS SECTION
Scale 1" = 100'
Cf
FIGURE 6
f3o
-1100
• • • •
D
1300 —
1200 —
#17SOUTHFIELD
Boring 2 (projected)
ry N35E
1100 — BRECCIA
1000 —
BEDROCK
#13 SOUTHFIELD
Boring 1
i 7
apparent dip of )edding
REGIONAL CROSS SECTION
Scale l" = 100'
So cl714
FIGURE 7
D'
— 1300
— 1200
— 1100
— 1000
E
1200
1100 —
Area of Proposed Construction
Area of thick colluvium
slopewash
ti West
lie., apparent dip of bedding
m
0
'a
m
E1200
— 1100
1000 — —1000
900 r — 900
REGIONAL CROSS SECTION
Scale 1" - 100'
FIGURE 8
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