8g. Presentation

South 188th St Tunnel Improvements

Item No.        8g_supp
Date of Meeting      June 27, 2023
S. 188th Street Tunnel
Project Authorization

                  Project Location
Control Building

West Portal                           Runway 34R                                                                East Portal

Ventilation Ducts                Taxiway A/B


                   Project Scope
Shared Port/City of SeaTac facility
Tunnel Scope Items:
•  Structural (crack sealing/spall repair)
•  Civil (signage)
•  Electrical (lighting, power, emergency
•  Mechanical (ventilation, fire suppression)
•  Communication and Special Systems (fire
detection/alarm, carbon monoxide
monitoring, security, egress/traffic

              Existing Facility Conditions

Egress Doorway          Fire Alarm Station             Walkway                Fire Hydrant


           Project Budget and Schedule
Project Budget:                       Project Schedule:
•  Previous Budget: $24,500,000       •  Construction Start Q4 2023
•  Revised Budget: $34,500,000         •  In-Use Date Q4 2024
Budget increase due to complete
ventilation redesign and higher
than anticipated escalation costs
Additional Airline MII approval not


                 Cone of Certainty

We are here


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