HomeMy WebLinkAbout19 - Balboa Island Seawall Coping Extension - PowerPointAugust 8, 2017
Item No. 19
Balboi Island Seawall Concrete Cap
(co-Dina extension) Prolect
Authorization to advertise and bid the project for construction
City Council Meeting August 8, 2017
Public Works Department
Project Improvements
1. Construct a —9 -inch
cap extension on
the south and north
sides of Balboa
Island.
2. Create closeable
"gaps" to access
beaches and public
docks.
LOCATION MAP
SCOPE OF PROJECT NOT IN SCOPE
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BALBCA ISLAND
COPING REPAIR
PROJECT
SCOPE OPPPOJECT N07IN SCOPE
Proposed ~9 -inch Cap Extension:
A.At
(Wave Overtopping during 2010 Storm)
Increase in Top of Wall Elevation
4 Provides Flood Protection for about 10 Years
LOCATION Elevation Now Proposed Elev.
Other L-uuationb 9.62'
Balboa Island N. 7.75'
Balboa Island S. 8.25'
Grand Canal 8.5'
Little
Island
E.
8.7'
Little
Island
S.
9.0'
8.5'
9.0'
* all elevations based on NAVD88 datum.
Difference
+9 inches
+9 inches
Example: Little Balboa Seawall Cap Extension
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PUBLIC WORKS DIRECTOR R.C.E. NO. 12806
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TYPE °B"COPING
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TYPE 'A° COPING.
N.T. S-
1188
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1988 L I me. 1 sl4-d
3 -Foot Wide Gaps in Seawall Cap for Beach Access
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9 -inch Stop Board Attached at 3 -Foot Wide Beach
Access Gaps
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_ - - -- - -- -- - -- -- Additional maintenance will ,be required
Construction Considerations
1. 17 work areas. Each work area would be approximately 450 feet in
length.
2. Construction would occur at no more than three non-consecutive work
areas at any given time.
3. Construction in each work area will take between 10 to 15 working days.
4. Work areas would occupy half of the boardwalk adjacent to the seawall
while other half will be available for public access and use.
5. Time for construction: —16 weeks (December break)
6. Engineer's Estimate: —$1.5 million
BALBOA ISLAND SEAWALL CONCRETE
CAP (COPING EXTENSION) PROJECT
Authorization to advertise and bid the project for construction
City Council Meeting August 8, 2017
Public Works Department
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