HomeMy WebLinkAboutCT 74-21; CARLSBAD OAKS BUSINESS PARK; REVIEW OF SIDEWALK CONDITIONS; 1987-10-06CIT 1(t-2I •P -w RECEIVED I
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
SOIL ENGINEERING & ENGINEERING GEOLOGY
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Bedford Properties Job No. 05-6574-006-00-00 2011 Palomar Airport Road Log No. 7-2310
Carlsbad, California 92009
Attention: Ms. Mary Jane Jagodzinski
SUBJECT: REVIEW OF SIDEWALK CONDITION
Palomar Airport Road and Loker Ave. East
Carlsbad Oaks Business Center
Carlsbad, California
Dear Ms. Jagodzinski,
In accordance with your request, we are providing recommendations
concerning our field meeting of September 30, 1987 at Carlsbad
Oaks Business Center. Jim Page, the City of Carlsbad field
representative, requested the meeting to discuss a separation
between the sidewalk and curb along the north side of Palomar
Airport Road, east of Loker Avenue East.
The separation between the sidewalk and curb is approximately 1/4
to 1 /2-inch wide horizontally, with 0 to 1/2-inch of vertical
displacement of the sidewalk above the curb. The area in
question is a portion of the improvements of Palomar Airport Road
for the Carlsbad Oaks Business Center development. The subgrade
of the curb, gutter and sidewalk consists generally of moderate
to highly expansive silt and clay soil. Expansive soils
underlying the sidewalk areprobably causing a displacement of
the sidewalk slab relative to the more deeply founded curb and
gutter structure. Moisture variations due to irrigation, rain
and sun exposure can result in this type of movement.
Discussed in the field meeting and recommended are three
alternatives to the problem.
6455 NANCY RIDGE DRIVE • SUITE 200 9 SAN DIEGO, CALIFORNIA 92121 • (619) 587-0250
Bedford Properties .ç t' Job No. 05-6574-006-00-00 October 6, 1987 t1) 1j4 Log No. 7-2310
Page 2 to
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/frill the open separation with a. suitable elastic filler and
monitor the situation .......y.
Remove the sidewalk and excavate the subgrade soils to a
depthof.2 feet. Replace the subgrade with a low (less
than.,20 expansion index) expansion potential fill
material. This would reduce but not eliminate the
potential for differential movement of the sidewalk, and
may act as areservoir for water, due to the increased
permeability of the granular import subgrade soil.
Remove the sidewalk and replace it utilizing steel dowels
drilled into thecurb. This reinforcement between the
sidewalk and curb may'limittFie amount of separation
between these two'-structures if concrete cracking or dowel
deformation does, not occur. Movement of the free side of
the sidewalk would continue to occur with moisture changes
in the sidewalk subgrade soils.
These recommendations should be elaborated upon if one is chosen
to be performed. Our opinion at this time is that the sidewalk
is performing adequately considering the type of soil materials
utilized during the grading of this project. It is our
understanding that the placement of the curb and gutter, and
sidewalk, are within the specifications of the City of Carlsbad.
Additionally, a granular base is sometimes recommended in other
cities, however, we recommend against this construction for
sidewalks. The granular base (usually 4 - 6 inches) acts as a
conduit for water and may aggravate the movement of the sidewalk.
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Bedford Properties . Job No. 05-6574-006-00-00
October 6, 1987 . Log No. .7-2310
Page
This opportunity to be of service is sincerely appreciated. If
you should have any further questions, please do not hesitate to
contact the undersigned at your convenience.
Very truly yours, . . . .
SAN DIEGO GEOTECHNICAL CONSULTANTS, INC.
Kenneth W. Shaw, C.E.G. 1251 . RobertA. Torres,.P.E. C 43077
Registration Expires: 6- . Registration Expires: 3-31-88 N ER Senior Geologist
KENNETH
Project Engineer
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