HomeMy WebLinkAbout1986-09-16; City Council; 8438-3; SLOPE STABILIZATION CHANGE ORDER - STAGECOACH PARK - SUPPLEMENTAL AGENDA BILLt' 1 CI-F CARLSBAD - AGENDWILL 'I w
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CITY ATT MTG.
DEPT. HE TITLE:
CITY MGI AGENDA BILL DEPT. p ' R
9/16/86 SLOPE STABILIZATION CHANGE ORDER - STAGECOACH PARK - SUPPLEMENTAL
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RECOMMENDED ACTION:
Approve slope stabilization work to be done by Chamac Inc. through a change
order and appropriate fmds from the Capital Improvement Project budget to co
the cost of the additional work. Rw~h~~tlohl NO. g 7 76.
ITFM EXPLANATION:
The City Council directed staff to provide additional information on the slop stabilization program at the August 26 meeting. Several alternatives have be
(alternate A)be undertaken. This would entail slope reconstruction and an
authorization for Chamac to proceed with the change order work. Geocon, a so
engineeringfirm hired by the City has reviewed their earlier findings on the
stability of the questionable slope. They have confirmed that there is
currently a 1.2 safety factor against slope failure. A safe standard measure
is 1.5 whereas 1 .O indicates minent failure. Geocon indicates that the 1.2 factor is unacceptable from a safety standpoint. Slope reconstruction will
eliminate potential. safety hazards, ongoing slope sloughing and will keep rep
costs to a minimum should a substantial failure occur.
DISCUSSION OF ALTERNATIVES
investigated and it is recanmerxied that the slope stabilization program
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A. _Reconstruct slope per soils engineer's recommendation.
Advantages :
1. Eliminates ongoing slope sloughing and major repair costs if a
2. Olivenhain Municipal Water District (O.M.W.D.) has endorsed staff':
3. Correcting the slope would alleviate possible litigation by develor
substantial failure occurs.
stabilization plan and has agreed to reactivate their water line.
and/or O.M.W.D.
Disadvantages:
1. Fiscal Impact.
2. Delay of 40 - 60 days in park construction.
B. Do nothing; repair as needed in the future.
Adva nt ages :
1. Should a failure not occur the City will bear no costs to repair t slope.
2. No time delays in park construction schedule.
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PAGE 2 OF AB {la3 8-3
Disadvantages :
1. O.M.W.D. has indicated they will not activate their water line.
2. Water service stoppages to upstrean developments may result in
3. There is a probability of ongoing slope sloughing and continuing
litigation against the City by O.M.W.D. adlor developers.
maintenance costs, If a major failure occured, substantial cost tc
Repair )
creating a road hazard and the potential for a vehicle accident anc
personal injury.
C. Relocate water line.
repair would result. (Refer to Exhibit D, for Worst Case Estimate
4. Should a major failure occur, road damage or blockage would occur
C1 Through Santa Fe Knolls development.
Advantages :
1. Would allow the 16 inch water line to be relocated around subjc t roub le area.
2. Fiscal impact - could save City up to $150,000 compared to wor: case slope stabilization construction estimate. (See Exhibit (
E) 3, No delay to park construct ion,
4. Olivenhain endorses this alignment. (Refer to letter by 0.M.W
attached .)
Disadvantages :
1. Would still leave road, electrical, gas and telephone utilitie.
jeopardy if failure occurs.
C2 Alongside Mision Estancia on the southeast side within the Anden buttress.
Not Feasible -- O.M.W.D. will not approve this alignment. Th
feel if the City does nothing to buttress the slope and prot e'
the road, a failure may occur causing movement in the road bel
This could jar the Anden buttress and cause a rupture in the
water line.
C3 Through the park.
Not Feasible -- Construction and trenching would disrupt alrea
installed park improvements resulting in additional costs and
delays. Secondly, another utility easement would encumber the
park. Thirdly, O.M.W.D. feels that the unst63le soil conditio
extends into the pa.rk.
D. Put slope back the way it originally was prior to grading.
Not Feasible -- This option would be prohibitive in cost due t
the vast quantity of cubic yards of dirt involved. One and possibly two bal If ields would have to be eliminated and an
existing maintenance building demolished.
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PAGE 3 of AB # 8 y3 "" a -3
E. Construct a crib wall to act as a buttress.
Not Feasible - - Cost would be greater than a slope Stdlility fill,
FISCAL IMPACT :
-, cost
*Alternate A - Repair Slope (high estimate) am (See Exhibit C)
*Alternate A - Repair Slope (low estimate) 274,000 (See Exhibit C)
Alternate B - Do nothing 0 - 600,000 (See Exhibit D)
Alternate C - Relocate Water Line 180,000 (See Exhibit E)
Alternate D - Rebuild slope to original state **N/A
Alternate E - Crib wall *W/A
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*Recanmendation.
*W/A prohibitive cost.
EXHIBITS:
1. Resolution No. E776
2. Exhibit A, Plan sb-wErea of instability.
3. Exhibit 8, Section of slope stabilization detail.
4. Exhibit C, Cost Estimate slope stabilization. 5. Exhibit D, Cost Estimate to repair slope failure damage.
6. Exhibit E, for realignment through Santa Fe Knolls.
ATTACHMENTS:
1 . Original Agenda Bill
2. Letter fran O.M.W.D.
3. Letter fran Geocon
4. Change order
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RESOLUTION NO.
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF CARLSBAD,
CALIFORNIA, APPROVING SLOPE STABILIZATION WORK TO BE DONI
BY CHAMAC, INC. AND APPROVING THE APPROPRIATION OF FUNDS
FROM THE CAPITAL IMPROVEMENT PROJECT BUDGET TO COVER THE
COST OF THE ADDITIONAL REQUIRED WORK
WHEREAS, a "stability fill" has been recommended .
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constructed to reduce the potential for shallow slope instab
for a portion of Stagecoach Park; and
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slope sloughing and repair; and 9
WHEREAS, slope stabilization would eliminate ongoi
10 WHEREAS, slope stabilization would eliminate possi
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damage to Mision Estancia and a 16 inch water line under the
and
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WHEREAS, the Olivenhain Municipal Water District h
endorsed staff's stabilization plan as protection for their
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I! work is performed; and 16
~ line and has agreed to reactivate their water line if stabil I
WHEREAS, reactivating the water service would all€
18 ,/ possible litigation by Olivenhain Municipal Water ijistrict i 1:
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19,'upstream developments requiring water service; and
20 WHEREAS, Chamac, Inc. is the Contractor responsib:
21 1; the construction and development of Stagecoach Community Pa:
22;, has been recommended by staff to perform the required slope
231 stabilization work; and I1 1
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24 ii /i WHEREAS, sufficient funds are available in the un
25: appropriated balance of the Public Facilties Fund to scppor
26:' cost of this project,
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NOW, THEREFORE, BE IT RESOLVED that the City Counl
the City of Carlsbad does hereby approve the slope stabiliz,
to be performed by Chamac, Inc. and approve the appropria
of funds from the unappropriated balance of the Public Faci
Fund, account No. 320-941, to account no. 320-840-1824-3191
cover the cost of the additional required work at Stagecoac
PASSED, APPROVED AND ADOPTED at a regular meeting
City Council of the City of Carlsbad, California, held on t
day of August 1986, by the following vote, to wit:
lo I AYES:
NOES: ILL I
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ABSENT :
MARY CASLER, Mayor
ATTEST:
ALETHA L. RAUTENKRANZ, City Clerk
(SEAL)
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/Anden buttress
SANTA FE KNOLLS
Park unrtable $lop ANDEN GROU
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STAGECOACH / SANTA FE KNOLL!
exhibit a
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EXHIBIT
15’ MIN.
3STANCIA a TT7 MISION-L- - - __ - - __ - “-c 1
STABILITY FILL BACKCUT hm \
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Q.?.
CRUSHED ROCK A6 b-4.
COLLECTOR DRAIN LINE
TO STORM DRAIN EX. PARK
5’ MIN.
STAGECOACH PARK REMEDIAL GRAD1
exhibit b
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REVISED SLOPE STABILIZATION COST ESTIMATE
(Based on Actual Bid Cost)
Hiqh
Change Order (Actual Construction Costs) - *$262 , 877
See Exhibit 3 and Change Order #4 attached
RSI Plan Revisions/Engineering Services 9,000
Soils Engineering & Site Observations * 28,000
City Engineering Services (Charged to * 13,000
Project) - 5%
Printing & Miscellaneous Charges 500
Sub-Total $315,377
Contingency - 5% 15,668
Total $329,045
*Worst Case Situation
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exhibit c
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August 22, 1986
TO : RAY PATCHETT, ASSISTANT CITY MANAGER
FROM: Mark Steyaert, Project Manager ,/@4&
STAGECOACH COMMUNITY PARK - COST ESTIMATE
SLOPE FAILURE DAMAGE
The following is a cost estimate to repair damage caused by a worst case slope failure that could occur in the future if the
slope is not stabilized at this time. This damage scenario
was developed from information in Geocon's May 15 soil report
which stated a failure could occur that would extend into
Mision Estancia, Therefore, this scenario makes the following
assumptions:
1. Mision Estancia and all utilities would have to
be replaced along the total length of the unstable area.
2, The OMWD water line would have to be replaced,
3. The slope stabilization work being proposed now
would have to be done to repair the slope.
4. If the water line broke, there would be damage to
the park caused by water pressure.
5. There could be damage to the slopes of the the
Santa Fe Knolls housing project adjacent to Mision
Estancia.
Replace Mision Estancia utilities (including water line). $250,000
Slope stabilization work (worst case $329,045
situation).
Repair park damage. $ 10,000
Repair housing development slope. $ 10,000 -
*TOTAL $600,000
*Worst case figure. Does not include inflation factor
(would cost more to do this work due to increased cost
Note: There is a potential for claims against the City under th
scenario due to damages and/or loss of water service. No
cost estimate can be determined for this.
&WAS : kw 6
r.. _. David Bradstreet, Parks & Recreation Director exhibil
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COST ESTIMATE 16 INCH WATER LINE THROUGH ANDEN
1,200 16" pipe
Design
SurveyIStaking
134,400
15,000
2 y 500
Inspection 1,500
Administration
Consulting Engineer
1,000
1 y 500
Geo Technician
Contingency 10%
Round to:
Credit for Developers 8" pipeline
TOTAL INSTALLATION APPROXIMATELY
3 y 500
159 , 400
15 y 940
175 , 340
180 , 000 7
38,400 *
$141,600
Removal of Existing pipeline estimated 10,000
*Final to be calculated based on a ratio of flows for the two pipeline sizes.
Note: Estimate provided by Olivenhain Municipal Water District.
exhibit