The Post-Tensioning Institute (PTI) recognized VSL with three awards in its biannual awards program announced in May. For Award of Excellence: Parking Structures, the Union Station parking garage expansion won honors. The project added 800 parking spots to the Washington, D.C. structure's existing 1500-space garage. This was accomplished by adding five levels of a cast-in-place post-tensioned concrete structural system over the existing bus deck. Because the expansion plan called for wide areas uninterrupted by columns, the engineer selected post-tensioned concrete girders, built monolithically with the beam and slab system. Post-tensioned concrete offered many advantages including a more durable, maintenance-free structure requiring no additional spray-on fireproofing. The new garage covers 295,000 square feet and cost $38 million.
The LeJeune Road Flyover took home the Award of Merit: Repair, Rehabilitation and Strengthening. The Florida DOT opted to construct the bridge, which connects LeJeune Road to Okeechobee Road, to ease exit traffic congestion at the Miami International Airport. Approximately 33-feet wide and 262-feet long, the flyover carries two lanes of vehicular traffic. Supported on two piers, it consists of a twin steel box girder bridge with an 8-inch cast-in-place composite deck. During initial construction, cracks were noticed in two piers before the project even opened to traffic. Because the Florida DOT wanted the structure to have a minimum 75-year service life, a durable, cost-effective, and aesthetically pleasing repair solution was required. The bridge also needed to be corrosion resistant since it ran over a canal. The project engineer devised an innovative turnkey repair and post-tensioned strengthening solution for the pier caps and columns, completed it in a mere four weeks. The project cost more than $14 million.
For the Award of Merit: Bridges, the Siebenthaler Avenue Bridge project in Dayton, Ohio, constructed from 2002–2004, replaced an older deteriorating structure and was designed to have a service life of more than 75 years. The structure carries vehicular traffic over a river and includes a bike-way and a sidewalk for pedestrians. Featuring four precast post-tensioned arches, it has an overall length of 263 feet and a 15,780-square-foot deck area. The arch motif was chosen to be consistent with other bridges in the city and the segmental arches were shaped and sized to consider shipping and lifting logistics. The four main arches are each comprised of three precast concrete segments joined with cast-in-place closure pours and post-tensioned strands. The main arches frame into massive thrust blocks using post-tensioned bars. The project cost $5,664,000. For more information, go to www.structural.net.