HomeMy WebLinkAboutAgenda Statement 1979/10/23 Item 12
CITY OF CHULA VISTA
COUNCIL AGENDA STATEMENT
Item No. 12
For meeti ng of 10/23/79
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ITEM TITLE
Resol ut ion 9fJ~ Approv ing Chang e Order Number One
and Authorizing Expenditure of Additional Funds for
East Naples Street Drainage Channel
City Engineer ~
SUBMITTED BY
ITEM EXPLANATION
(4/5TH'S VOTE REQUIRED YES
NO~)
Meza-Hab Construction Company is the contractor for the
construction of an improved drainage channel south of East
Naples Street between Monserate Avenue and Helix Avenue.
The contract dated July 19, 1979, was awarded by City
Council Resolution No. 9653 on June 29, 1979.
...
BACKGROUND:
This project was budgeted in the amount of $74,400 in the
1977-78 Capital Improvement Program. The purpose of the
project was to eliminate a recurring flooding problem during
peak flows and to eliminate objectionable odors and mosquito
breeding ponds during dry weather.
Engineering originally designed a channel to carry the
design 50 year flood consisting of a concrete bottom and 2-2
1/2 foot high masonry block walls. This project was
advertised twice and the City twice rejected the low bids of
$251,000 and $151,000. The City Council upon rejecting the
bids the second time upon staff recommendation directed
staff to redesign and readvertise a drainage project in
reduced scope which would eliminate the odors and mosquito
problem.
DMH:nr/AN-005
(continued on supplemental page)
Agreement_
Other
EXHIBITS
Resolution~ Ordinance
Pl at~
Notification List___
ENVIRONMENTAL DOCUMENT: Attached___ Submitted on
FINANCIAL IMPACT
Cost of project is being financed with revenue sharing funds. City
will assume maintenance of the improvements upon completion of the
project. Approval of the Change Order for covering the natural channel
banks with air blown concrete will reduce the amount of maintenance by
City forces. Maintenance should be no higher than for any other improved
channel.
STAFF RECOMMENDATION
Approve Change Order No. One in the amount of $11,318 increasing the
contract cost to $70,018.00 and approving 26 working day extension of
time to contract making contract completion date December 6, 1979.
Authorize the additional expenditure of $6,644.42.
BOARD/COMMISSION RECOMMENDATION
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COUNCIL ACTION
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Agenda Item No. 12
For Meeting of 10/23/79'
Supplemental Page Two
Engineering staff redesigned the project consisting of a
concrete paved channel invert 10 feet wide. This design
will carry a 1 year storm or 30 percent of the design flow
and eliminate the odor and mosquito problem. A contract was
awarded to Meza-Hab Construction Company in the amount ~f
$58,700 to construct the project.
THE ISSUE:
Once construction of the channel had begun, engineering
staff began receiving complaints from adjacent property
owners.
The adjacent property owners are concerned about erosion of
the channel banks during moderate to peak flows and the
resulting damage to their property. They have asked staff
if anything can be done to prevent this erosion. Over the
past 20 years this channel has eroded from an 18 inch ditch
to a channel G feet in depth.
The existing soil type is a lightly cemented sandstone. The
contractor has shown that in place this soil is hard to cut
but once it is exposed to water it crumbles easily.
The concrete paved channel invert which Meza-Hab is
constructing will increase the velocity of flow in the
channel over what it was originally. For storms over 1 year
frequency, the water will flow outside of the concrete paved
channel invert and will start to erode the natural channel
banks. The increased velocity would increase the rate at
which erosion originally occurred.
The channel as it is being constructed prevents the channel
from cutting deeper but does not prevent the erosion of the
channel banks during peak to moderate flows.
SOLUTION:
Engineering staff has investigated the complaints and
concerns of the property owners and find that they are
valid. There is a potential for continued erosion to the
channel banks during moderate to peak storms.
The erosion can be prevented by cutting the existing banks
to a 1:1 slope for a height of 1.3 feet and covering them
with 4 inches of wire mesh reinforced air blown concrete.
This will result in a modified concrete trapezoidal channel
capable of carrying the 50 year design flow without erosion
to the channel banks.
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Agenda Item No. 12
For Meeting of 10/23/79
Supplemental Page Three
This solution will also satisfy the concerns of the property
owners and will for all intents and purposes satisfy the
concept of the original design with masonry walls.
The original plans and specifications call for the placement
of approximately 4200 square feet of 2-inch thick air blown
mortar on graded channel slopes created by the construction
of the concrete paved channel invert.
Engineering staff is recommending that the item for ~-inch
thick air blown mortar be deleted from the contract and that
9,116 square feet of 4-inch thick wire mesh reinforced air
blown concrete be substituted by contract change order.
The contractor, Meza-Hab Construction Company, has submitted
a written proposal to construct the 9,116 quare feet of wire
reinforced 4-inch air placed concrete on the channel bank
for a total increase in the cost of the contract in the
amount of $11,318.
The cost of installing the 4-inch air placed wire reinforced
concrete including additional grading is S~5,03h. The
change order would also include deletions from the original
contract of $13,718 consisting of 2-inch air placed concrete
~,40~), 8-inch air placed concrete berm ($320) and trench
s'horing ($4,996).
The contractor is also requesting that the contract time be
increased ~6 additional working days to perform the extra
work. Engineering staff believes that this request is
reasonable.
This project is financed by revenue sharing funds. The
amount of funds available for construction is $71,331.93.
Approval of the change order will increase the contract to
S70,018, for an increase in contract cost of $11,318.
$12,514.42 in unencumbered funds are available in the
project account. Approval of the change order will require
an additional authorized expenditure of $6,644.42 above that
previously authorized by the City Council in the amount of
$64,570 on June 2h, 1979.
The City Engineer recommends approval of the change order
and a time extension to the contract of 26 working days to
perform the additional work. If approved, the contract
completion date will be changed to December 6, 1979.
A transparency of channel section is available for Council
viewing.
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FINANCIAL STATEMENT:
Project budgeted amount
original Contract
Materials
Unencumbered Balance
Contract Change Order
Cont ing enc ies
Revised Contract Amount
Contingencies
Requested Authorized Expenditure
Previous Authorized Expenditure
Agenda Item No. 12
For Meeting of 10/23/79
Supplemental Page Four
571,331.93
58,700.00
117.51
12,514.42
11,318.00
1,190.42
70,018.00
1,191.).42
71,214.42
,4,570.00
Additional Authorized Expenditure ~S44.42
Form No. F-229
12/73
CERTIFICATE OF CITY/DIRECTOR OF FINANCE
Certification of Unappropriated Balance
I HEREBY CERTIFY that the money required for the
appropriation of funds for the purpose set forth in the attached
resolution is available in the Treasury, or is anticipated to
come into the Treasury, and is otherwise unappropriated.
Amount $
Fund
Purpose
Bidder
Director of Finance
The City of Chula Vista
Date
By
Certification of Unencumbered Balance
I HEREBY CERTIFY that the indebtedness and obligation
to be incurred by the contract or agreement authorized by the
attached resolution can be incurred without the violation of any
of the provisions of the Charter of the City of Chu1a Vista, or
the Constitution or the laws of the State of California, that
sufficient monies have been appropriated for the purpose of said
contract, that sufficient monies to meet the obligations of the
contract are actually in the Treasury, or are anticipated to come
into the Treasury to the credit of the appropriation from which
the same are to be drawn, and that said monies now actually in
the Treasury, together with the monies anticipated to come into
the Treasury, to the credit of said appropriation are otherwise
unencumbered.
Amount Not to Exceed $ 6,644.42
600-6000-RS05
Director of Finance
The City of Chula Vista
Date
10/18/79
By
Fund CIP
Dept./Activity
CIP
Purpose Change Order 1 - E. Naples Drainage Channel
Bidder Meza-Hab Construction Company
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Certificate No.
34