BOGDONOV PAO ASSOCIATES LTD. Structural Engeneers

PROJECTS Bridges  ALSF 16L

Retained by the FAA, BPA designed the ALSF (Approach Lighting System with Sequenced Flashing Lights) bridge project that supports the runway landing lights for Runway 16L at the SEATAC International Airport. 

The total length of the system is about 730 m (2,400 ft), in which two 183 m (600 ft) long bridge segments are required to span over Interstate 528 and environmentally sensitive wetlands north of the airport. 

In order to optimize the structure, a wind tunnel test was conducted to more closely understand the actual wind effects on the structure. As well, a time-history analysis was conducted in order to predict the performance of the system in an earthquake likely to occur in the Seattle Area. The time-history analysis subjects a computer model of the structure to a simulated earthquake. These tests resulted in savings of 15% on the structure weight for the two 183m (600 ft) long spans. 

Bridge Model

ADDITIONAL IMAGES