Grand River Center Floor Settlement Project Award
TO: The Honorable Mayor and City Council Members
FROM: Michael C. Van Milligen, City Manager
SUBJECT: Grand River Convention Center
Floor Settlement Remediation Project
(C I P's: 3501991)
DATE: September 27, 2012
Assistant City Engineer Bob Schiesl is recommending that the improvement contract for
the Grand River Center be awarded to Hayward Baker, Inc. in the amount of $250,500.
The Grand River Center (GRC) was opened to the public in October, 2003. In the
summer of 2007, differential settlement was observed around the lobby and escalators.
The geotechnical engineer of record, Terracon, and the deep foundation contractor for
the GRC, Hayward Baker, were called in to inspect and subsurface borings were
performed around the escalator area. However, the subsurface investigation proved to
be inconclusive, the fill material under the floor slab appeared to be of high density and
no apparent voids were encountered directly under the slab. The decision was made to
retain the services of Hayward Baker to perform a specialized polyurethane foam
grouting application to raise the slab-on-grade system. This method was effective in
correcting the settling occurring in this specific area of the building.
Since 2010, monthly inspections of the GRC have taken place. During this time, staff
began to notice what appeared to be minor re-occurring settling in the lobby area
around the escalator. Staff began to closely monitor the situation.
During the February 2012 monthly visit, the GRC showed signs of accelerated floor slab
settlement in the escalator area, but the settlement had also moved laterally outward to
the administrative offices, lobby and pre-functions areas.
In March 2012, the City's survey crew measured baseline elevation readings throughout
the main floor areas of the lobby, pre-function, restroom and offices. Based on the
recorded elevations, settlement readings ranged from .25 inches to 2.64 inches, with
the most significant settlement occurring at the base of the escalators (2.64").
Upon further inspection of the GRC, it does not appear that any of the building structure
that is supported on deep foundation auger cast piling is showing signs of distress or
movement. This would include the second floor conference rooms, the river room, and
the underground parking structure. It appears that the primary main floor areas of the
GRC that are experiencing the majority of the settlement are those areas supported by
stone column foundations.
Competitive sealed bids were received on the Grand River Convention Center — Floor
Settlement Remediation Project on September 20, 2012.
Based on the original 2002 Terracon geotechnical report, the deep soil conditions
beneath the now-existing structure are highly variable and consist of miscellaneous fill
materials, including sand, clay, limestone and concrete fragments, brick, cinders, wood
chips/sawdust and other organic materials, which extended to depths ranging from
about 8 to 23 feet beneath the original ground level.
Due to the depth and variable composition of the subsurface fill material, both City staff
and Terracon feel that the deeper variable fill layers need to be improved or densified to
reduce the risk of future settlements while also stabilizing and supporting the building
structure on a more competent soil layer located deep beneath the original ground level.
The Hayward Baker remediation work plan submitted on September 20 proposes to drill
a series of holes in a grid-like pattern directly through the interior concrete floor which
will allow for the installation of supplemental compaction grout columns that will extend
to a depth of approximately 20 feet below the existing floor slab. The deep compaction
grout improvement technique should help densify and stabilize the variable fill materials
and provide additional supplemental support to the existing stone column foundations
and improve support under the existing floor slab areas.
The Hayward Baker remediation work plan also proposes the installation of support
piling (micropiles) around the base of the escalator pit foundation. This will allow the
piles to directly transfer the escalator load through the variable fill to a stronger soil layer
at a depth of approximately 25 feet below the existing floor slab. Once at an adequate
bearing depth, the piles can be hydraulically jacked to raise the escalator pit foundations
back to near the original elevation. The additional pile support for the escalators should
be more effective in reducing the potential of future settlements and thus allowing the
escalators should remain stable.
The final ground improvement technique that is proposed is to apply a high density
polyurethane foam grout injection directly under the floor slab. The polyurethane foam
grout will be used to raise and re-level the main floor slab-on-grade areas.
Based on the review and evaluation of the proposals submitted, both City staff and
Terracon believe that the Hayward Baker remediation proposal provides a technical and
comprehensive approach for both long-term settlement control and improving the
existing slab-on-grade conditions on site in the short-term. The proposed remediation
2
solution to install grout columns to densify and stabilize the variable fill material layers
and provide additional supplemental support under the existing floor slab areas in
addition to adding micropiles that extend through the variable fill layer to a stronger soil
layer to support the escalator should be effective in reducing the potential of future
settlements and allowing the GRC main floor areas to remain stable.
Although Peerless Compaction Grouting, Inc. / Uretek ICR Heartland provided the
lowest cost proposal, Assistant City Engineer Bob Schiesl believes that it is in the City's
best interest to recommend that the improvement contract for the Grand River
Convention Center — Floor Settlement Remediation Project be awarded to Hayward
Baker, Inc. in the contract amount of $250,500.00.
Staff has consulted with City Attorney Barry Lindahl regarding the State of Iowa
competitive bidding statute as it pertains to the "lowest responsible bidder" provisions.
Barry is comfortable with the competitive bidding procedure used by the City and the
evaluation process that followed to allow staff to recommend the "responsible bidder" in
the best interest of the City.
City Attorney Barry Lindahl is of the opinion that the award of the improvement contract
for the Grand River Convention Center — Floor Settlement Remediation Project to
Hayward Baker, Inc. is consistent with Iowa law.
Staff has identified sufficient funding to cover the immediate Floor Settlement
Remediation Project and to restore the operational use of the escalators. The project
cost remaining of $187,550 which includes decorative concrete replacement, carpet
replacement, restroom tile replacement, drywall and ceiling tile repair, painting, project
contingency, and construction engineering, administration and inspection will be funded
by the one million dollar one-time reserve that was established by City Council in Fiscal
Year 2013.
I concur with the recommendation and respectfully request Mayor and City Council
approval.
/72AAh kt1&1
Michael C. Van Milligen
MCVM:jh
Attachment
cc: Barry Lindahl, City Attorney
Cindy Steinhauser, Assistant City Manager
Teri Goodmann, Assistant City Manager
Robert Schiesl, Assistant City Engineer
Gus Psihoyos, City Engineer
3
Masterpiece on the Mississippi
Dubuque
kard
All- America City
2012
TO: Michael C. Van Milligen, City Manager
Gus Psihoyos, City Engineer
FROM: Robert Schiesl, Assistant City Engineer
SUBJECT: Grand River Convention Center
Floor Settlement Remediation Project
(CI P's: 3501991)
Engineering Department
City Hall
50 W. 13th Street
Dubuque, Iowa 52001
563.589.4270
563.589.4205 (fax)
www.cityofdubuque.org
DATE: September 27, 2012
INTRODUCTION
The enclosed resolution authorizes the award of the construction contract for the Grand
River Convention Center — Floor Settlement Remediation Project.
BACKGROUND
The Grand River Center (GRC) was opened to the public in October, 2003. In the
summer of 2007, differential settlement was observed around the lobby and escalators.
The geotechnical engineer of record, Terracon, and the deep foundation contractor for
the GRC, Hayward Baker, were called in to inspect the observed settlement locations.
Based on the recommendations of both Terracon and Hayward Baker, subsurface
borings were performed around the escalator area. However, the subsurface
investigation proved to be inconclusive, the fill material under the floor slab appeared to
be of high density and no apparent voids were encountered directly under the slab. The
decision was made retain the services of Hayward Baker to perform a specialized
polyurethane foam grouting application to raise the slab -on -grade system. This method
was effective in correcting the settling that occurring in this specific area of the building.
Since 2010, monthly inspections of the GRC have taken place. During this time, staff
began to notice what appeared to be minor re- occurring settling in the lobby area
around the escalator. Staff began to closely monitor the situation.
During the February 2012 monthly visit, the GRC showed signs of accelerated floor slab
settlement in the escalator area, but the settlement had also moved laterally outward to
the administrative offices, lobby and pre- functions areas. Bob Schiesl was informed and
began follow up discussions with both Terracon and Hayward Baker.
In March 2012, the City's survey crew measured baseline elevation readings throughout
the main floor areas of the lobby, pre- function, restroom and offices. Based on the
recorded elevations, settlement readings ranged from .25 inches to 2.64 inches, with
the most significant settlement occurring at the base of the escalators (2.64 ").
During this same time period, the escalator was experiencing operational issues and the
escalator service technician was called in to review. Based on the magnitude of the
settlement at the base of the escalator and the rotational movement observed at the top
of the escalator, the decision was made to turn off the escalator in the interest of public
safety and to prevent any further damage from occurring.
Upon further inspection of the GRC, it does not appear that any of the building structure
that is supported on deep foundation auger cast piling is showing signs of distress or
movement. This would include the second floor conference rooms, the river room, and
the underground parking structure. It appears that the primary main floor areas of the
GRC that are experiencing the majority of the settlement are those areas supported by
stone column foundations.
DISCUSSION
Staff has been working with Terracon and other specialty contractors to discuss and
evaluate non - destructive repairs and remediation alternatives and to establish
budgetary cost projections. Due to the highly specialized nature of the floor system
settlement repair and the proprietary methods and techniques used to perform the
subsurface soil stabilization and remediation work, the City developed plans showing
the settlement and remediation areas; a scope of work, specifications and performance
measures that the specialty contractors will use to prepare and submit a proposed
remediation work plan along with an associated bid proposal cost for the work.
The City only bid the Floor Settlement Remediation Project at this time. Staff will solicit
quotes from janitorial contractors to perform daily cleaning services in addition to
retaining the services of Schindler Escalator for a technician to be on -site while
remediation work is performed around the escalator. All other anticipated restoration
work, such as the decorative concrete in the lobby entrance, carpeting, and tile will be
informally bid separately and completed following the floor settlement remediation work.
BID RESULTS
Competitive sealed bids were received on the Grand River Convention Center — Floor
Settlement Remediation Project on September 20, 2012. A summary of the bid
proposals received is as follows:
Contractor Name
Proposal Cost
Peerless Compaction Grouting, Inc. / Uretek
$229,686.00
Hayward Baker, Inc.
$250,500.00
BID PROPOSAL EVALUATION
Both City staff and Ken Beck, P.E., Senior Principle at Terracon have reviewed the
proposals submitted by both Peerless Compaction Grouting (Peerless) and Hayward
Baker. Attached is a bid proposal evaluation letter provided by Terracon.
The Peerless remediation work plan proposes to drill a series of holes directly through
the interior concrete floor which will allow for the injection of high density polymer resin
components to lift, realign, stabilize and fill any potential voids under the escalator and
floor slab areas. Although the Peerless remediation approach has proven results in
raising foundations and floor slabs that have settled, their proposed depth of treatment
is limited to approximately 6 feet in most areas and about 10 feet beneath the
escalators.
When the GRC was constructed, the foundation system called for approximately 6 feet
of compacted engineered fill to be placed over the stone columns and beneath the main
floor slab -on -grade areas. This was confirmed by the 2007 subsurface borings
performed around the escalator area which indicated an engineered fill layer was
present at the boring locations to depths ranging from about 6 to 7% feet below the floor
slab. The subsurface investigation also indicated that the fill material under the floor
slab appeared to be of high density and no apparent voids were encountered directly
under the slab.
As a result of our investigations, it is our opinion that the engineered fill layer directly
under the slab is not likely responsible for the larger than expected settlement observed
to date.
Based on the original 2002 Terracon geotechnical report, the deep soil conditions
beneath the now - existing structure are highly variable and consist of miscellaneous fill
materials, including sand, clay, limestone and concrete fragments, brick, cinders, wood
chips /sawdust and other organic materials, which extended to depths ranging from
about 8 to 23 feet beneath the original ground level.
Due to the depth and variable composition of the subsurface fill material, both City staff
and Terracon feel that the deeper variable fill layers need to be improved or densified to
reduce the risk of future settlements while also stabilizing and supporting the building
structure on a more competent soil layer located deep beneath the original ground level.
The polymer injection remediation method proposed by Peerless, in some areas may
only extend into the shallow engineered fill layer directly under the slab and does not
provide for long term improvements to the deeper variable fill layer.
The Hayward Baker remediation work plan proposes to drill a series of holes in a grid -
like pattern directly through the interior concrete floor which will allow for the installation
of supplemental compaction grout columns that will extend to a depth of approximately
20 feet below the existing floor slab. The deep compaction grout improvement
technique should help densify and stabilize the variable fill materials and provide
additional supplemental support to the existing stone column foundations and improve
support under the existing floor slab areas.
The Hayward Baker remediation work plan also proposes the installation of support
piling (micropiles) around the base of the escalator pit foundation. This will allow the
piles to directly transfer the escalator load through the variable fill to a stronger soil layer
at a depth of approximately 25 feet below the existing floor slab. Once at an adequate
bearing depth, the piles can be hydraulically jacked to raise the escalator pit foundations
back to near the original elevation. The additional pile support for the escalators should
be more effective in reducing the potential of future settlements and thus allowing the
escalators should remain stable.
The final ground improvement technique that is proposed and consistent with both the
Peerless and Hayward Baker remediation plans is to apply a high density polyurethane
foam grout injection directly under the floor slab. The polyurethane foam grout will be
used to raise and re -level the main floor slab -on -grade areas.
Based on the review and evaluation of the proposals submitted by both Peerless and
Hayward Baker, both City staff and Terracon believe that the Hayward Baker
remediation proposal provides a more technical and comprehensive approach for both
long -term settlement control and improving the existing slab -on -grade conditions on site
in the short -term. The proposed remediation solution to install grout columns to densify
and stabilize the variable fill material layers and provide additional supplemental support
under the existing floor slab areas in addition to adding micropiles that extend through
the variable fill layer to a stronger soil layer to support the escalator should be more
effective in reducing the potential of future settlements and allowing the GRC main floor
areas to remain stable.
RECOMMENDATION
Although Peerless Compaction Grouting, Inc. / Uretek ICR Heartland provided the
lowest cost proposal, based on the Floor Settlement Remediation Plan submitted by
Hayward Baker, I believe that it is in the City's best interest to recommend that the
improvement contract for the Grand River Convention Center — Floor Settlement
Remediation Project be awarded to Hayward Baker, Inc. of Roselle, Illinois in the
contract amount of $250,500.00.
Staff has consulted with City Attorney, Barry Lindahl, regarding the State of Iowa
competitive bidding statute as it pertains to the "lowest responsible bidder" provisions.
Attorney Lindahl is comfortable with the competitive bidding procedure used by the City
and the evaluation process that followed to allow staff to recommend the "responsible
bidder" in the best interest of the City. Attorney Lindahl has provided legal authority in
Iowa that governing officials have the power to adopt such offer or offers, propositions,
or bids, and enter into such contract or contracts, as they deem to be to the best interest
of the municipality. The Iowa supreme court has often said that the Legislature has
vested a judicial discretion in the governing officers of the municipality, and the amount
of the bid is, of course, a matter for careful and weighty consideration, but other
considerations may tip the balance in favor of a higher bid.
City Attorney Lindahl is of the opinion that the award the improvement contract for the
Grand River Convention Center — Floor Settlement Remediation Project to Hayward
Baker, Inc. is consistent with Iowa law.
BUDGET IMPACT
The updated overall planning level estimate to remediate, repair and restore the Grand
River Convention Center main floor settlement areas is as follows:
Based on the Bid Proposal Cost provided by Hayward Baker, the estimate of probable
cost to complete the immediate Floor Settlement Remediation Project and restore the
operational use of the escalators is as follows:
Estimate
Bid Award
Floor Settlement Remediation
$250,000.00
$250,500.00
Janitorial Cleaning Service
15,000.00
15,000.00
Escalator Service and Repair (Service Contract)
75,000.00
75,000.00
Decorative Concrete Replacement
35,000.00
35,000.00
Carpet Replacement
50,500.00
50,500.00
Restroom Tile Replacement
10,000.00
10,000.00
Drywall & Ceiling Tile Repair
10,000.00
10,000.00
Painting
10,000.00
10,000.00
Contingency
45,550.00
45,550.00
Construction Engineering, Administration & Inspection
50,000.00
50,000.00
Total Project Cost
$551.050.00
$551.550.00
Based on the Bid Proposal Cost provided by Hayward Baker, the estimate of probable
cost to complete the immediate Floor Settlement Remediation Project and restore the
operational use of the escalators is as follows:
Estimate
Bid Award
Floor Settlement Remediation (Hayward Baker, Inc.)
$250,000.00
$250,500.00
Janitorial Cleaning Service
15,000.00
15,000.00
Escalator Service and Repair (Service Contract)
75,000.00
75,000.00
Construction Engineering, Administration & Inspection
23,500.00
23,500.00
Total Project Cost
$363,500.00
$364,000.00
The project funding summary is as follows:
CIP No.
Fund Description
Fund Amount
3501991
Grand River Center Floor Leveling
$ 45,279.00
1021214
Veteran's Memorial Ball Field
130,250.00
1002198
Grand River Center Mechanic Room Screen
12,000.00
1022113
Grand River Center Replace Carpet
70,768.00
1002197
Grand River Center Paint Exhibit Hall
70,203.00
1022391
Grand River Center Office Painting
35,000.00
Total Project Funding
$363.500.00
S aff has identified sufficient funding to cover the immediate Floor Settlement
Remediation Project and to restore the operational use of the escalators. The project
cost remaining of $187,550 which includes decorative concrete replacement ($35,000),
carpet replacement ($50,500), restroom tile replacement ($10,000), drywall and ceiling
tile repair ($10,000), painting ($10,000), project contingency ($45,550) and construction
engineering, administration and inspection ($26,500) will be funded by the one million
dollars one -time reserve that was established by City Council in Fiscal Year 2013.
ACTION TO BE TAKEN
I recommend that the City Council adopt the attached resolution awarding the Grand
River Convention Center - Floor Settlement Remediation Repair Project to Hayward
Baker, Inc. of Roselle, Illinois, in the contract amount of $250,500.00.
Prepared by Robert Schiesl, Assistant City Engineer
cc: Jenny Larson, Budget Director
Barry Lindahl, City Attorney
Marie Ware, Leisure Services Manager
Chris Lyons, Engineering Technician
K: \PROJECTS \GRCC - Grand River Convention Center Repairs\2012 - Floor Settlement Remediation Project \Council & Staff
Documentation \Award
RESOLUTION NO. 276 -12
AWARDING PUBLIC IMPROVEMENT CONTRACT FOR THE GRAND RIVER
CENTER FLOOR SETTLEMENT REPAIR PROJECT
Whereas, sealed proposals have been submitted by contractors for the Grand
River Center Floor Settlement Repair Project (the Project) pursuant to Resolution No.
237 -12 and Notice to Bidders published in a newspaper published in the City of
Dubuque, Iowa on the 7th day of September, 2012, and
Whereas, said sealed proposals were opened and read on the 20th day of
September, 2012 and it has been determined that Hayward Baker, Inc. of Roselle,
Illinois with a bid proposal in the amount of $250,500.00, is the responsive, responsible
bidder for the Project, and
Whereas, the Hayward Baker, Inc. remediation proposal provides a more
technical and comprehensive approach for both long -term settlement control and
improving the existing slab -on -grade conditions on site in the short -term, and
Whereas, it has been determined that it is in the best interest of the City of
Dubuque to enter into an improvement contract with Hayward Baker, Inc. for said
Project.
NOW THEREFORE, BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY
OF DUBUQUE, IOWA:
That a Public Improvement Contract for the Project is hereby awarded to
Hayward Baker, Inc. and the City Manager is hereby directed to execute a Public
Improvement Contract on behalf of the City of Dubuque for the Project.
Passed, approved and adopted this 1st day of Octobe , 2012.
Attest:
Roy D. Buol, Mayor
September 27, 2012
City of Dubuque
City Hall
50 West 13`h Street
Dubuque, Iowa 52001
Attention: Mr. Robert Schiesl, P.E.
Assistant City Engineer
RE:
lrerracon
Geotechnical Engineering Addendum Letter
Grand River Center Floor Settlement Remediation Project
500 Bell Street
Dubuque, Iowa
Terracon Project No. 07075032
Dear Mr. Schiesl:
At your request, Terracon Consultants, Inc. has reviewed the proposals submitted by Uretek
ICR ( Uretek) and Hayward Baker, Inc. (HB) regarding the Grand River Center Floor Settlement
Remediation Project. A summary of our review is provided in this letter.
Although Uretek's approach may typically work to raise a floor slab that has settled, their depth
of treatment is limited to 6 feet in most areas and about 10 feet beneath the escalators. Based
on our 2007 subsurface exploration, an engineered fill layer was present at our boring locations
to depths ranging from about 6 to 71/2 feet depths below the floor slab. Reportedly, this fill layer
was placed and compacted in accordance with the project specifications during construction of
the convention center. As a result of our observations, it is our opinion that this layer is not
likely responsible for the larger than expected settlement observed to date. As discussed in our
2002 report, highly variable fill in the area of the escalator and office areas extended to depths
in the range of about 15 to 20 feet below the floor slab, and in our opinion, this material is more
likely responsible for the greater than expected settlements. For this reason, it is our opinion
that the deeper variable fill layer needs to be improved /densified to reduce the risk of future
settlements.
HB's proposal does provide more extensive means to reduce the risk of future movement of the
escalator and floor slab. Supporting the escalator on micropiles that extend through the variable
fill and into the native sands should provide positive support and reduce the risk of future
settlement. The pressure grouting beneath the floor slabs will also improve the variable fill
materials and should be more effective to reduce future settlements than the shallower
improvement provided by Uretek's method; in some areas, Uretek's depth of improvement will
not extend very far into the variable fill layer. HB's final step using the polyurethane grout will lift
the slabs to match the existing surrounding grades, just as Uretek proposes to accomplish with
their method.
Terracon Consultants, Inc., 870 40th Avenue, Bettendorf, Iowa 52722
P [563] 355 -0702 F [563] 355 -4789
Geotechnical • Environmental • Construction Materials • Facilities
Geotechnical Engineering Addendum Letter
Grand River Center Floor Settlement Remediation Project • Dubuque, Iowa
September 27, 2012 • Terracon Project No. 07075032
lierracon
Although we have not performed additional exploratory services to better evaluate the causes of
the additional settlement observed to date, it is likely due to changes within the variable fill layer.
In our opinion, we believe that HB provides a more technical and positive proposal to address
future settlement by not only supporting the escalator on micropiles that extend through the
variable fill layer and into the underlying native soils, but by also improving /densifying the entire
variable fill layer beneath the referenced floor slab areas. In closing, HB's proposal appears to
address the apparent root of the problem which is the variable fill layer, whereas Uretek's
proposal will provided limited improvement in this layer and will essentially just fix the current
condition by lifting the slabs to match the grade of the surrounding slabs.
We appreciate the opportunity to be of further service to you on this project. This Addendum
Letter should be considered a part of our original Geotechnical Report prepared for this project
(Terracon Job No. 07025002, dated February 7, 2002), and is subject to the same qualifications
and conditions outlined in that report. Please contact us if you have any further questions
concerning this letter or our previous reports.
Sincerely,
Terracon Consultants, Inc.
W. Ken Beck, P.E.
Iowa No. 10684
WKB/ KCB/ N:\ Projects\2007\07075032/07075032 Addendum Letter.docx
Attachments
ti) 'Kole C.Berg, P.E.
Iowa No. 17013
Responsive • Resourceful • Reliable 2