PORT OF SEATTLE 
MEMORANDUM 
COMMISSION AGENDA               Item No.      6d 
ACTION ITEM 
Date of Meeting     August 5, 2014 
DATE:    July 29, 2014 
TO:      Tay Yoshitani, Chief Executive Officer 
FROM:   Michael Ehl, Director, Airport Operations 
Wayne Grotheer, Director, Aviation Project Management 
George England, Capital Program Leader, Aviation Project Management 
SUBJECT:  Service Tunnel Renewal/Replacement (CIP #C102112) 
Amount of This Request:        $4,500,000   Source of Funds:   Airport Development
Fund (ADF) and
Est. Total Project Cost:         $27,900,000 
Future Revenue
Bonds 
ACTION REQUESTED 
Request Commission authorization for the Chief Executive Officer to execute a professional
services agreement for design development of the Service Tunnel Renewal/Replacement project
at Seattle-Tacoma International Airport in the amount of $4,500,000 of an estimated total project
cost of $27,900,000.
SYNOPSIS 
The Airport service tunnel is located below the Airport arrivals drive, and runs the full length of
the main terminal. It structurally supports the entire arrivals drive, and critical portions of the
departure drive. The service road within the tunnel provides the only access to the central loading
dock and central heating plant located at tunnel midpoint that are critical to supporting
continuous 24 hour airport operations. Two employee parking bus stops are also located within
the tunnel. The roof of the tunnel supports a range of utilities also essential to main terminal
operations. The 2,500-foot-long service tunnel was designed, constructed, and commissioned in
phases between 1968 and 1974.
The Airport Service Tunnel Renewal/Replacement project will bring the structures up to current
seismic code and improve their earthquake reliability. Work include s improvements to existing
shear walls, improved column footings, beam reinforcement, and additional seismic bracing.
Ongoing seismic upgrades at the Airport have included upgrades to the parking garage (1990),
the central loading dock area (1997), main terminal baggage and ticketing (1998 and 1999),
Airport roads and bridges (2001), and additional main terminal seismic retrofitting (2004). 


Template revised May 30, 2013.

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 2 of 7 
This request is to retain a consultant to conduct further site investigations, conditions surveying, 
and to design the project. The information gathered during design will inform staff whether to 
award  a single construction contract or several  phased contracts,  to address the various
construction risks when retrofitting the existing structural, electrical, and mechanical systems in
the tunnel. 
This project was approved by the airlines under the Majority-In-Interest process in July 2014.
This project is included in the 2014-2018 capital budget and plan of finance. The project will
include a project labor agreement. 
BACKGROUND 
The service tunnel structure is complex, consisting of several different structural designs
mirroring themselves as one moves  north and south from the  center of the tunnel  (see
Attachment A). The central area structure was upgraded in 1997 as part of the Ground Access
and Seismic Improvements project. The Service Tunnel Renewal/Replacement project will
address the remaining portions of the service tunnel that have not been upgraded. 
An earlier condition assessment of the various portions of the service tunnel identified a number
of seismic vulnerabilities in every portion of the service tunnel, with the exception of the loading
dock area. The study also identified the need to accurately locate and investigate the numerous
utilities located throughout the tunnel. Several of the utilities within the tunnel are vital to 24/7
operations of the Airport.
PROJECT JUSTIFICATION AND DETAILS 
The service tunnel is an essential Airport facility and is structurally linked to other critical
Airport infrastructure. The roof of the service tunnel forms the support for most of the Airport's
arrivals drive and portions of the departures drive. The service tunnel provides critical secured
access to the central heating plant and its supporting infrastructure, the central loading dock
(used by commercial delivery vehicles to support continuous 24-hour terminal operations), and
the employee busing operation. The service tunnel provides structural support for multiple
critical utilities, offices, locker rooms, storage rooms, and emergency generators. A catastrophic
failure during a seismic event could cripple airport operations above and within the service
tunnel. 
The service tunnel is an essential element of Airport infrastructure that has not been strengthened
or upgraded to current seismic building codes. Seismic standards have changed greatly since the
construction of the service tunnel, and an update is needed. Retrofitting the service tunnel will
improve its survivability and strength, while also extending the service life of the facility.
Without seismic upgrades, there are unreinforced portions of the service tunnel that will be at
risk of severe damage or localized failure during a seismic event. This in turn could lead to
localized failure of the departures and arrivals drives, and possible utilities failures. A 2009
study by Kennedy/Jenks indicated that each section of the service tunnel has unique seismic

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 3 of 7 
deficiencies, with the transition structures between the cast-in-place concrete sections and the
sections supported by structural framing being the areas of greatest risk. There are also failing
expansion and construction joints that are causing water-related deterioration and damage to the 
tunnel structure. Unique design solutions will be required for different sections of the service
tunnel due to the variations in the existing structural designs.
Proposed improvements that will be considered during design include strengthening columns and
their footings, reinforcing structural beams, tying structural beams together, and adding shear
walls and panels. Other critical repairs within the service tunnel include improving the drainage
and repairing failed structural and expansion joints that are allowing backfill material to move
through joints in the service tunnel walls. 
After considering several different contracting methods to accomplish the project, staff
determined that design-bid-build was the most efficient. It  was determined that this method
would allow the Port to best manage the design, develop phasing that minimizes operational
impacts, and manage unforeseen site conditions and risks.  There is also an opportunity to
consider phased construction contracts  where the Airport can leverage lessons learned from the
first contract to improve our bid documents and reduce our risks with the subsequent contract(s).
A consultant team will be hired with experience in structural, mechanical, electrical, and
geotechnical engineering design to survey existing utilities, conduct site investigations, and
prepare design documents and specifications.  The team will also contain expertise in
constructability analysis. Extensive surveying needs to be conducted to more precisely locate the
numerous existing utilities within the tunnel. F urther investigative work is needed to better
determine unknown conditions staff speculates may exist. These additional efforts will reduce,
but not eliminate, the Port's risks for inadequate as-built information and unknown conditions. 
Given the confined nature of the tunnel and the type of improvements necessary to reinforce the
various structures, the project will develop plans to mitigate operational impacts to the loading
dock, employee parking buses, and central plant. Extensive stakeholder feedback will be sought
and incorporated into the design documents.
Project Objectives 
The project will bring the service tunnel into compliance with modern life/safety seismic
standards and code, and would: 
Enhance the survivability of the service tunnel in a major seismic event. 
Extend the useful life of the service tunnel. 
Improve public safety and maintain Airport operations. 
Scope of Work 
Staff is recommending that the design of the project include a geotechnical analysis, deficiency
assessment of each section, a detailed survey, constructability review, phasing analysis, and

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 4 of 7 
design plans and specifications to address a seismic reinforcement strategy for each section. It is 
also estimated that $314,000 of regulated materials management abatement work will be
required during the project.
The design effort will focus on the following outcomes: 
Improving structural performance and reducing damage in all levels of earthquake 
Reducing interference/connectivity issues between the service tunnel and the primary
terminal structure and parking garage in all levels of earthquake (helping to preserve the
integrity of the terminal and parking garage) 
Reducing the likelihood of disruption to utilities servicing the terminal in all levels of
earthquake 
Performing constructability analyses 
Reducing drainage issues and repairing drainage-related damage 
Correcting existing voids and reducing future voids and other movements that may cause 
instability and damage, even in everyday conditions 
Increasing the lifespan of the existing structural components 
Compatibility with adjacent current and planned projects 
Minimizing operational impacts during construction, while maintaining operational
continuity 
Schedule 
MII approval                    July 2014 
Design Authorization               August 2014 
Construction Authorization            2nd Quarter 2016 
Construction Completion             4th Quarter 2018 
FINANCIAL IMPLICATIONS 
Budget/Authorization Summary              Capital     Expense   Total Project 
Original Budget                     $24,009,000          $0   $24,009,000 
Budget increase                       $3,577,000     $314,000    $3,891,000 
Revised budget                     $27,586,000     $314,000   $27,900,000 
Previous Authorizations                   $65,075          $0      $65,075 
Current request for Authorization            $4,500,000          $0    $4,500,000 
Total Authorizations, including this request     $4,565,075          $0    $4,565,075 
Remaining budget to be Authorized        $23,020,925     $314,000   $23,334,925 
Total Estimated Project Cost             $27,586,000     $314,000   $27,900,000 
Project Cost Breakdown                     This Request       Total Project 
Design                                  $4,500,000         $4,550,000 
Construction                                    $0        $21,240,000

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 5 of 7 
RMM Abatement                           $0        $314,000 
State & Local Taxes (estimated)                        $0         $1,796,000
Total                                      $4,500,000         $27,900,000 
Budget Status and Source of Funds 
The Service Tunnel Renewal/Replacement project (CIP #C102112) was included in the 2014-
2018 capital budget and plan of finance with a budget of $24,009,000. The budget increase is an
adjustment to the preliminary cost estimate for increased inflation and clarification of project
scope. The budget increase will be transferred from the Aeronautical Allowance CIP (C800404)
resulting in no net change to the Airport capital budget. The funding source for this project will
be the Airport Development Fund (ADF) and future Aviation bonds. The Port anticipates
issuing bonds in late 2014 or early 2015 to fund a number of projects. This project was approved
by the airlines under the Majority-In-Interest process in July 2014. 
Financial Analysis and Summary 
CIP Category             Renewal/Enhancement 
Project Type              Renewal and Replacement 
Risk adjusted discount rate     N/A 
Key risk factors             N/A 
Project cost for analysis        $27,900,000 
Business Unit (BU)          Roadways 
Effect on business performance  NOI after depreciation will increase 
IRR/NPV             N/A 
CPE Impact             $.07 in 2019 
Lifecycle Cost and Savings 
The existing service tunnel structure is nearing the end of its design service life. The completion
of this project will help to extend the useful life 20 to 50 years.  We do not anticipate a
significant change in the operating and maintenance costs for the service tunnel. 
STRATEGIES AND OBJECTIVES 
This project supports the Century Agenda objective of meeting the region's air transportation
needs at Sea-Tac Airport for the next 25 years.  Renovating existing assets is critical to
maintaining capacity. 
The Service Tunnel Renewal/Replacement project is consistent with the Airport's strategic goal
to operate a world-class  international airport by ensuring safe and secure operations and
managing our assets to minimize the long-term total cost of ownership. The project will: 
Upgrade existing structures to meet current life/safety seismic standards 
Extend the useful life of existing structures and increase survivability

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 6 of 7 
TRIPLE BOTTOM LINE 
Economic Development 
The service tunnel is an essential Airport facility. The service tunnel supports a portion of the
departures drive and all of the arrivals drive. It also serves the central loading dock, the central
plant, the employee bus operation, most of the utilities serving the main terminal and several
other key functions. Keeping this facility whole helps keep the Airport operational. Failure of
the facility impacts terminal access, logistics, critical operations and public safety. 
Environmental Responsibility 
Preservation of an existing facility minimizes environmental impact. A complete rebuild of this 
facility would result in a very large civil works project that is unnecessary with targeted
improvements to the existing infrastructure.
Community Benefits 
The safety and convenience of the travelling public and Airport employees depends on a service
tunnel that can remain standing through and after the area's next substantial earthquake. Taking
steps to protect and preserve this essential facility is far less expensive, and much less disruptive, 
to operations than having it fail. By taking precautions now, rather than waiting until after a
catastrophic seismic event, the Port can better control the cost and tempo of the upgrade. This
minimizes the cost to the public and our airline partners. 
It is anticipated that there will be opportunities for women and minority owned firms, as well as
small and disadvantaged business enterprises, on this project. The selected build team will be
strongly encouraged to provide opportunities for, and seek engagement of, these firms. 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1)    Do nothing. This option perpetuates a  known hazard.  This is not the
recommended alternative. 
Alternative 2)  Upgrade transition structures only. The transition structures are, nominally, the
most at-risk portions of the service tunnel. However, n ot completing the other portions of the
service tunnel that contain critical infrastructure and support the drives still leaves the Airport at
risk. This is not the recommended alternative. 
Alternative 3)  Upgrade of all of the remaining unreinforced portions of the service tunnel.
This option allows a proactive approach to preserve public safety, protect Port infrastructure, and
ensure continuous Airport operations.  This is the recommended alternative. 
ATTACHMENTS TO THIS REQUEST 
Attachment A  Vicinity Map and Details.

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 29, 2014 
Page 7 of 7 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
April 1, 2014  Commission was briefed on the Service Tunnel Renewal/Replacement
Project. 
March 27, 2007  Commission authorized funds for the Parking Garage/Service Tunnel
Pre-Design project.