HomeMy WebLinkAbout23-17 Addendum No. 1City
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Oshkosh
Addendum No.1
City Contract 23-17
EAST PARKWAY AVENUE WATERSHED DETENTION BASIN -
CONSTRUCTION
TO ALL CONTRACTORS:
Based on questions received related to the excavation support, which will be necessary for the
construction of the retaining wall on the east and west sides of the detention basin, the design of
the wall is being re-evaluated to raise the bottom elevation of the footing along the majority of
the wall. No modification is anticipated at the location of the inlet sewer pipe where the bottom
of footing will remain at Elevation +749 ft. The re -design will raise the bottom of the footing
elevation for the majority of the remainder of the wall to Elevation +753 ft in an effort to reduce
the excavation support requirements. In order to raise the bottom of the footing elevation,
construction surcharge loading adjacent to the wall will be limited to 100 pounds per square foot
(psf). Revised drawings will be made available to bidders on Tuesday, August 8, 2023 in
Addendum No. 2.
Listed below are Bidding Questions (Q) received and the Bidding Answers (A) provided to
contractors:
(Q) Will the project require site security? With the drop offs involved will simple safety
fencing be enough or are we going to need an actual construction fence?
(A) As discussed in Section SP-13, site security and site safety are the responsibility of the
Contractor. The Contractor shall submit a safety and security plan to the City prior to the
start of construction. It is the Contractor's responsibility to determine measures which are
appropriate for the activities which will be performed.
(Q) If the Contractor plans to encroach on the CN Railroad Right of Way, are any delays in
securing access cause for a time extension or is securing the necessary permissions from
the railroad entirely at the Contractor's risk?
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City Hall, 215 Church Avenue P.O. Box 1130 Oshkosh, WI 54903-1130 http://www.cl,oshkosh.\Wi.us
(A) Time is of the essence for the completion of the Project, due to planned construction on
Grand Street in 2024. However, consideration will be given to extending the substantial
completion date beyond November 24, 2023 if delays in the Project are solely a result of
responsiveness of CN in securing a construction easement or right of entry. In order to
consider this, the City will need to see that progress has been made and the Contractor
shall prove that every attempt possible has been made in coordinating and
communicating with CN.
(Q) There appear to be three 12" by 12" Nyloplast inlets along the backside of the west wall.
They appear to daylight through the wall with a check valve. Do these also connect into
the 6" hard stick pvc underdrain behind the wall? Since there is not item for these, I would
assume that all of these along with the 6" drain tile is incidental to the wall? _
(A) The profiles and details on Sheet C-7 are intended to show that the 6" perforated PVC
line behind the west retaining wall will be connected into the Nyloplast square inlets
before discharging through the check valves and into the basin. As indicated in Section
SP-22, furnishing and installing drain tile, drain basins, and backflow preventers is
considered incidental to the wall construction.
(Q) The formliner limits extend 1' minimum below grade. Alternate 1 is for concrete staining
of the formliner. A 28 day concrete cure time is typically required prior to placement of
concrete stain per manufacturer recommendations. Provided the formliner limits, the last
1' of fill will not be able to be placed until after the formliner is applied 28 days after the
last concrete pour. Assuming 2 weeks to complete concrete staining, placement of the last
1' of fill, and restoration; the last concrete pour must be on October 101" to achieve +the
November 24th completion date should Alternate 1 be selected. Temperature conditions
in November may require the wall to be heated and housed to meet concrete stain
manufacturer application temperature requirements as well. Would the owner consider
keeping November 24th as an interim completion date and revise the contract completion
date to spring/summer 2024 to complete the concrete staining if Alternate 1 is selected?
(A) The formliner limits should extend one foot (1') below grade as shown �on the Drawings;
however, the concrete staining would be limited to the form liner which is extending
above finished grade. Concrete staining, if selected, could be deferred to spring of 424
as part of final completion. Substantial completion will be determined once the basin has
been constructed, concrete has been poured, final grading has been established, and final
restoration is completed. Final completion will include concrete staining, if selected.
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(Q) Can elements of an earth retention system extend off City property and be left in place
after completion of the project?
(A) Elements of the temporary shoring system need to remain on City property and no
elements can remain in place after construction is complete.
(Q) Can you provide photos of the color scheme at the Baldwin Basin?
(A) See pictures below:
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If you have any questions regarding this Addendum, please contact me at (920) 236-5065 between
the hours of 8:00 a.m. and 4:00 p.m. weekdays or Jeremy Thomas of AECOM at (847) 702-6639 or
by email at ieremy.thomas@aecom.com.
Sincerely,
VQZ
Alyssa Deckert, P.E.
Civil Engineering Supervisor
AD/tit
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