Item No. 8e_supp
Meeting Date: January 12, 2021
Passenger Loading Bridge (PLB)
Replacement Phase 3
Tyler Salisbury
Project Manager, AV-PMG

Background
PLBs are one of the highest used pieces of equipment at SEA.
Approximately 75 active bridges in 2019, SEA saw an average of 336,000 passengers per PLB.
Compared to a national average of 220,000 passengers per PLB for the top 20 airports.
Bridges have a 25-year service life
Bridge failures have a significant impact to operations and customer experience.
New technologies to improve turnaround time and customer
experience.
Safedock, Improved Wifi, and JetDock.
2021 Construction season
Opportunity with NSAT
2022 Construction season
Looking for opportunities with airfield pavement project
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Location & Overview
Replace 7 Passenger Loading Bridges

4-Year Program (2021-2024)

Concourse C & D

What is Involved?  Foundation
Bridge foundations are being brought
up to the current building code.
Drilled shaft
(35'-45' deep with 8'x8'x4' Cap)

Expanded footing
(18'x18' foundation)

What's Involved?  Bridge
What is new?
Fixed walkway section
Bridge section
Support columns
Control/Communication boxes
400 Hz system refresh  New
Gate boxes
Ethernet connections
Upgraded Controls and safety
sensors
Prep for future improvements
New interior! No carpet!

Risks
Gate outage scheduling
Limited number of gates that can be out for
construction and other project delays can
affect the PLB replacement schedule.
Competing projects for the dry weather
construction window.
Unknown Subgrade
Foundation excavations have uncovered
unknown structures not identified during the
survey activities.
Underground piping was identified prior to
construction. However, it was not where it had
been identified.

Opportunities
Gate Outage Scheduling
Potential for overlapping project schedules with gate outages (Airfield pavement
and Mega projects).
Changing bridge replacement order to align with other projects.
Frequent coordination meetings with AV-Ops and other projects that have gate
outages.
Gates C18 and C20 are being accelerated to take advantage of gates opening at the
north satellite
Alternative procurement methods
Design Build approach to increase the number of replacements in a year.

Cone of Certainty
W e are here

Alternative 1  Delay Project
Cost Implications: Approximately $20,000 would need to be expensed;
potential for additional costs if PLB fails during delay and is rushed to be
replaced.
Pros:
Delayed capital investment
Cons:
Bridges will be operating beyond their service life
Increased replacement cost and time if replaced as an emergency
Future replacement projects may cost more
Increased risk of gate outages
Other projects will be needed to replace smaller components of the bridge to keep
functional
Outdated technology may not support other bridge improvements (Safedock, Jetdock)

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Alternative 2  PLB Bridge Replacement Only
Cost Implications: $13,500,000
Pros:
Replace all 7 PLBs that are at end of service life
Upgrade bridge foundations to meet current code
Install new equipment with capacity for future improvements
Cons:
Higher capital investment
Does not replace the 400 Hz gate boxes that are near or beyond end of life
A future project and shutdowns will be required to replace 400 Hz gate boxes

10

Alternative 3  PLB Bridge Replacement and New
400 Hz Gate Boxes
Cost Implications: $14,000,000
Pros:
Replace all 7 PLBs that are at end of service life
Upgrade bridge foundations to meet current code
Install new equipment with capacity for future improvements
Replace 7 Aging 400 Hz gate boxes
Cons:
Highest capital investment

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