As part of a multi-billion dollar expansion program at Baltimore-Washington International Airport (BWI), the Maryland Aviation Administration (MAA) improved the access to and from the main terminal. VSL was contracted to provide various types of post-tensioning and repair services to the general contractor for the existing parking structure improvements and on the restructuring of the existing and new departure level bridge deck. 

In the existing six-story garage, three new stair and elevator towers were constructed using VSL’s monostrand post-tensioning system on eighteen poured-in-place concrete slabs. The installation of new moving walkways required 10’ by 20’ openings to be cut into the existing post-tensioned concrete slab. VSL locked-off the existing monostrand post-tensioning tendons and created slab openings that measured approximately 10’ by 20’. The work required the use of innovative repair strategies to maintain the desired post-tensioning forces in the surrounding slab without excessive shoring. 

At the eight entrance locations of the existing elevated bridge that carries vehicular traffic through the departure level of the airport, the existing deck was replaced with post-tensioned segmental slabs. The new segments were then post-tensioned together using VSL’s SA6-4 anchorages, 0.6” diameter strands and PT-Plus duct. The slab segments were cast off-site and erected during non-peak hours, while the openings were protected with a temporary bridge during peak hours. 

The existing elevated bridge was connected to a new 1100’ concrete bridge through several crossovers at regular intervals. The bridge was constructed using precast segmental construction, with the segments cast at an off-site casting yard and erected span-by-span. The bridge contains 123 segments approximately 52’ wide and 10’ long. The segments were temporarily post-tensioned using high-strength post-tension bar at four locations across the segment face. The permanent post-tensioning tendons were installed in the 8 ½” thick slab using four 0.6” diameter strands, while the integral edge beams used VSL’s ES6-7 and ES6-19 anchorages. 

In order to limit the disruption to airport operations, the curbside expansion project was completed in several phases over a five-year schedule. Strict maintenance of traffic requirements were imposed to allow ongoing utilization of the garage and airport entrance. Completed in 2006, the BWI Curbside Expansion greatly adds to the airport’s capacity and improves its ease of use.