HomeMy WebLinkAboutTIS 2023-01-17 Item 2A - Public Safety Plan - Public Works Campus Phase 2 UpdateCity of Tukwila
Allan Ekberg, Mayor
INFORMATIONAL MEMORANDUM
TO: Transportation and Infrastructure Services Committee
FROM: Brandon Miles, Business Relations Manager
CC: Mayor Allan Ekberg
DATE: January 13, 2023
SUBJECT: Public Works Campus, Phase 2
Project No. 92230601
Cost Estimate for Adapting the Existing Building vs. New Construction
ISSUE
Update on the City of Tukwila Public Works Campus Phase 2. This update will focus on providing comparative cost
estimates for adapting the existing building versus new construction.
BACKGROUND
Miller Hayashi Architects has prepared a memo' discussing the comparative cost estimates, and issues with
adapting and reusing the existing building, compared with construction of a new building. These costs are for
comparative purposes and not intended to be cost estimates for construction. This analysis only focuses on the
reuse or new construction of 26,000 square feet. With either option an additional 14,000 square feet of building space
will need to be constructed. Additionally, the cost estimate does not include the site improvements and other site
elements. These combined cost estimates will be presented to the City Council in February when staff presents its
preferred design option.
Several of the program elements would not be able to fit or additional costs would be incurred to allow the elements
to fit on site.
DISCUSSION
The total estimated cost for reusing the existing building is $30,715,978 versus a total estimated cost of $31,819,133
for new construction of a 26,000 square foot building. In addition to the concerns raised by Miller in its memo to the
City, the project team also has the following concerns with adaptive reuse of the building.
1. It's difficult to fit all the project elements on the site. In order to fit these elements on the property, structured
parking and other elevated structure options would need to be considered. This would add an additional
cost not required for the new construction. In lieu of the structured options, the City would need to acquire
additional land or defer the disposition of the Longacres and/or Minkler Shop property. Delaying the future
sell of these properties would result in an opportunity cost of between $6-12 million. Additionally, one of the
stated goals in the public safety plan was to consolidate public works operational activities on one property.
2. Adaptive reuse of the building does not meet one of our program objectives to future proof the site for future
City needs. Creating a large open space provides maximum flexibility for the City in the future for
modifications.
3. Reusing the existing building would require visitors of the building and city employees to walk from their cars
through an active shop yard.
FINANCIAL IMPACT
N/A
RECOMMENDATION
Discussion only.
ATTACHMENT: Memo from Miller Hayashi, dated January 10, 2023.
The project team consisting of SOJ, and John Palewicz reviewed and provided comments on the memo and the
conclusions.
2 These are not construction cost estimates but are cost estimates to compare two possible alternatives. The project 1
team will present construction cost estimates for the preferred option in February.
Miller Hayashi Architects LLC
118 N. 35th St.
Suite 200
Seattle, WA 98103
T 206 634 0177
F 206 634 0167
millerhayashi.com
MEMORANDUM
Date: 1/10/2023
Regarding: Tukwila Public Works Maintenance & Engineering Building Test -to -fit
Analysis of the Existing UPS Building
To: Brandon J. Miles, Business Relations Manager, City of Tukwila
From: Laura Maman, Principal, Miller Hayashi Architects
INTRODUCTION
This memorandum provides information and analysis in regards to adapting the existing UPS
Facility at 11231 East Marginal Way South in Tukwila as part of the development project for the
Tukwila Public Works Maintenance & Engineering Building. This memorandum addresses the
condition of the existing building, the feasibility of implementing the Public Works program in the
existing building, and seeks to compare the conceptual cost of renovation to the cost of new
construction.
DESCRIPTION OF STRUCTURE
The following description and observations are based on a field visit conducted by a structural
engineer on October 12, 2022. The one-story loading dock facility is framed with structural steel
bents and cold formed steel purlins and girts with metal roofing and siding. The diaphragm
consists of steel rods. The vertical lateral force resisting system in the north -south direction are
the steel bents. There is no obvious vertical lateral force resisting system in the east -west
direction. The loading bay structure is elevated approximately 4 feet above the first floor of a
small two-story office area. Based on the age of the building it is expected that the building would
be supported by conventional shallow reinforced concrete foundations. There is deterioration,
distortion, or damage at structural elements throughout the loading bay area including many
damaged purlins and girts.
The site supporting soils are liquefiable, and in the event of a significant earthquake the existing
structures would see settlement that could cause collapse. Recommended foundation retrofits
would include adding concrete grade beams and foundations along with piles to —100 feet deep.
Deterioration of the existing structure at the loading bay would require repair/replacement of a
significant portion of the existing structure including the roof and the exterior walls.
There are significant deficiencies in the lateral force resisting system. The existing lateral force
resisting system would be expected to perform poorly in an earthquake based on new science
and engineering standards which have developed since these structures were built. A full
seismic upgrade would be required to comply with current building codes.
A change in use and occupancy would trigger a substantial alteration and the requirement for full
compliance with all applicable current codes including energy code and accessibility regulations.
PROGRAMMATIC CONSIDERATIONS
The existing building is approximately 26,000 square feet. This accommodates less than 65% of
the approximately 40,000 square feet of space identified for the Public Works interior program
elements.
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The existing building does not readily accommodate ADA access. New ramps and an elevator or
lift would be required to navigate between the various levels.
The one-story building is an inefficient use of limited site area. The position of the existing
building on site poses challenges for site circulation and traffic flow.
COST COMPARISION EXERCISE
Refer to the attached cost comparison. This comparison is useful to understand the value of the
existing building within the larger context of conceptual options for development of the site. The
cost comparison looks at the building only, it does not include costs related to site improvements
or site utilities. This is not a detailed cost estimate. It is a rough order of magnitude comparison
intended primarily to provide an understanding of the value of the existing building.
CONCLUSIONS
1. Extensive modifications would be required to repair the existing structure. New foundations
and a new lateral structural system would be required for earthquake safety to meet current
building code.
2. Comprehensive replacement of the building envelope (exterior walls and roof) would be
required to meet current energy code.
3. Replacement of the mechanical system would be required to meet the program needs and
current mechanical code. Extensive modification to the electrical system and most likely
replacement of the electrical service would be required to meet the programmatic needs and
current codes.
4. Retaining the structure and adapting it to fit the Public Works program would present
significant design challenges and would likely diminish the functionality and efficiency of the
new facility.
5. Retaining the one-story building results in less open site area. The test -to -fit process identified
that it is a challenge to fit the needed site program on the property along with a one-story
building. Retaining the existing one-story building may require more expensive strategies to
implement site program, would reduce future flexibility, and may necessitate retaining other
city properties resulting in opportunity cost of property that would otherwise become surplus.
6. Renovation of an existing building inherently has a greater potential for the discovery of
unforeseen existing conditions; therefore, a higher estimating contingency has been applied to
the renovation scenario in the cost comparison exercise.
ATTACHMENTS
Cost Comparison
Photos of the existing facility
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Tukwila Public Works Maintenance and Engineering Building - Test -to -Fit Phase
COST COMPARISON
Draft 1/10/2023
RENOVATION
Hazmat Abatement
Selective Demolition
Seismic Upgrades
Foundation Retrofit
Roof Replacement
Cladding Replacement
HVAC, Plumb, FS
Electrical, Telecom
Interior Tenant Improvements
Vertical Conveyance
subtotal
General Conditions
Estimating and Design Contingency
General Contractor Overhead and Profit
Escalation to Spring 2025
Soft Costs, project related costs
NEW CONSTRUCTION
Hazmat Abatement
Building Demolition
New Construction
Deep Foundation System
subtotal
General Conditions
Estimating and Design Contingency
General Contractor Overhead and Profit
Escalation to Spring 2025
Soft Costs, project related costs
SF
26000
26000
26000
26000
26000
26000
26000
26000
26000
26000
$/5F
$15 $390,000
$15 $390,000
$45 $1,170,000
$27 $702,000
$40 $1,040,000
$40 $1,040,000
$65 $1,690,000
$65 $1,690,000
$140 $3,640,000
$10 $260,000
$12,012,000
10% $1,201,200
25% $3,003,000
$16,216,200
8% $1,297,296
14% $2,451,889
$19,965,385
35% $10,750,592
$30,715,978
Comments
abatement of hazardous materials while protecting elements to remain
selective removal of building elements while protecting elements to remain
full seismic upgrade to lateral force resisting system to meet building code
retrofit of foundations to address poor soil conditions (liquefiable soils on site)
removal of existing roof assembly, replacement with energy code compliant insulation and new roofing
removal of exterior cladding, replacement with energy code compliant insulation and new cladding
new mechanical systems to meet energy code requirements (existing systems not sufficient for intended use)
new electrical system to meet energy code requirements (existing system not sufficient for intended use)
interior walls, floor finishes, ceiling finishes, doors, relites, casework, etc.
allowance for new elevator
contingency at concept phase to account for unknowns
Project Cost, 26,000 SF renovation only, excludes site improvements
SF $/SF
26000 $12 $312,000 abatement of hazardous materials for full bldg demo
26000 $10 $260,000
26000 $450 $11,700,000 generalized cost per square foot for new construction
26000 $25 $650,000 deep foundations to address liquefiable soils
$12,922,000
10% $1,292,200
20% $2,584,400 contingency at concept phase for new construction
$16,798,600
8% $1,343,888
14% $2,539,948
$20,682,436
35% $11,136,696
$31,819,133
Project Cost, 26,000 SF new building only, excludes site improvements
Miller Hayashi Architect PLLC
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Photos of 11231 East Marginal Way South
From King Count Parcel Viewer:
L,
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Photos of 11231 East Marginal Way South
Existing office area:
Exterior relationship to grade:
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