N.G. JACOBSON & ASSOCIATES, INC.

NGJ was the Prime Designer to the Port of Seattle for the Structural Upgrade of the Level 3 Shuttle Van Lanes in the Seattle-Tacoma International Airport Parking Garage.

The original parking garage was built in the late 1960’s and early 1970’s and enlarged in the early 1990's.  The central portion is a cast-in-place concrete waffle slab and the end portions are composed of a post-tensioned concrete slab and beam structural system.  The original design indicated that the structure was designed for a parking live load of 50 psf.  The Port of Seattle required that the parking structure supporting the van lanes be strengthened to support an H-15 highway loading as defined by the “American Association of State Highway and Transportation Officials”  (AASHTO).

In 1998, NGJ performed a Structural Load Capacity Review and Report for the Level 3 Shuttle Van Lanes.  This report concluded that the garage's original structural capacity was insufficient to support an H-15 highway loading.  In 1999, utilizing findings from this review, NGJ analyzed the existing structure and designed the structural strengthening of the structure supporting the van lanes.  The structural strengthening consists of the addition of a combination of steel beams and carbon fiber reinforced polymer.