BALTIMORE, MD (July 14, 2006) -- VSL - a nationwide specialty-construction company focusing on the design, manufacture, and installation of concrete reinforcement systems - recently received three awards from the Post-Tensioning Institute (PTI). VSL was recognized this year with an Award of Excellence: Parking Structures for the Union Station parking garage expansion project in Washington, D.C.; an Award of Merit: Repair, Rehabilitation and Strengthening for the LeJeune Road Flyover in Miami, Fla.; and an Award of Merit: Bridges for the Siebenthaler Avenue Bridge project in Dayton, Ohio. PTI's bi-annual awards program, announced May 8 at PTI's Technical Conference and Exhibition, honors superior post-tensioning projects in the construction industry. The judges evaluate the submittals based on creativity, innovation, ingenuity, cost effectiveness, functionality, constructability and aesthetics. Projects can be submitted into seven categories including buildings, parking structures, slab-on-ground, strengthening/ rehabilitation, bridges, industrial/special applications and international. "We are honored that three of our projects were selected for PTI awards this year," said Scott Greenhaus, President of VSL. "The PTI awards are well-known for recognizing the industry's most challenging projects, which makes this achievement extremely gratifying for our team. The awards also are significant as this year marks the 50th anniversary of VSL in the United States."
Award of Excellence: Parking Structures
VSL received the Award of Excellence: Parking Structures for the Union Station parking garage expansion project in Washington, D.C. Visited by more than 20 million people each year, Union Station is one of the area's most popular tourist destinations featuring Amtrak, commuter and subway train service, in addition to upscale shops and restaraunts. Originally built in 1908, Union Station is an architectural and historic landmark recognized as one of the busiest stations in the country. Adjacent to Union Station is a 1,500-space parking garage. During this project, parking for an additional 800 cars was gained by adding five levels of a cast-in-place, post-tensioned concrete structural system over the existing bus deck. The new garage covers 295,000 square feet and cost $38 miillion, including more than $1 milllion of post-tensioning, supplied by VSL. The expansion plan called for wide areas uninterrupted by columns. The engineer selected post-tensionsed concrete girders, built monolithically with the beam and slab system, to achieve the 98-foot spans. Post-tensioned concrete offered many advantages over steel trusses, including a more durable, maintenance-free structure requiring no additional spray-on fireproofing. The bonded system was selected in order to reduce the quantity of mild reinforcement in these girders, thus reducing congestion and saving time and money. The Union Station parking garage expansion was recongized by the jury as an innovative solution to a challenging engineering problem. The efficient use of light-weight concrete and post-tensioning allowed the construction of an additional floor with the existing foundations. The use of bonded as well as unbonded tendons optimized performance of the structure. The jury also noted how the design avoided a separate transfer system with the use of post-tensioning. In addition to VSL, other key team members include:
Architect: Tim Haahs and Associates
Engineer: Tim Haahs and Associates
Contractor: Clark Concrete Contractors LLC
Award of Merit: Repair, Rehabilitation and Strengthening
The LeJeune Road Flyover, located in Miami, Fla., also earned VSL top honors. The Miami International Airport is one of the busiest and most heavily trafficked transportation centers in the world. To help ease traffic congestion exiting the airport, the Florida Department of Transportation opted to construct the LeJeune Flyover, a bridge that connects LeJeune Road to Okeechobee Road. The total project cost was more than $14 million, with an unseen repair costing $426,305 in post-tensioning, supplied by VSL. Approximately 33-feet wide and 262-feet long, the flyover was designed to carry two lanes of vehicular traffic. The superstructure is supported on two piers and consists of a twin, steel box girder bridge with an 8-inch cast-in-place composite deck. One of the piers, Pier Two, has a cantilevered arm that gives the pier an L-shape and is set on a footing that is below-grade. The second pier, Pier Three, is a hammerhead, T-shaped pier. During initial construction of the three-span, twin steel box-girder bridge over LeJeune, cracks were noticed in two piers before the project even opened to traffic. The Florida Department of Transportation wanted the structure to have a service life of at least 75 years and required a repair solution for the cracks that would be durable, cost-effective and aesthetically pleasing. Further, the bridge was located over a canal, so the structure and the repair solution needed to be resistant to corrosion from natural elements. The project engineer devised an innovative turnkey repair and post-tensioned strengthening solution for the pier caps and columns, completed in a mere four weeks. The LeJeune Road Flyover repair project was considered, by the jury, a practical solution to a common as-built condition. Post-tensioning was an economical solution to rehabilitate the structure with the least amount of disruption to the public. Extra measures like HDPE ducts and high-performance grouts ensured that the repair was durable. Other team members include:
Engineer: Keith and Schnars
Contractor: MCM Corporation
Other contributors: Williams Form Engineering
Award of Merit: Bridges
VSL also was honored as the post-tensioning supplier for the Siebenthaler Avenue Bridge project in Dayton, Ohio. Constructed in 2002 through 2004, the Bridge 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 also includes a bikeway as well as a sidewalk for pedestrians. The Siebenthaler Bridge features four precast post-tensioned arches, at an overall length of 263-feet and a 15,780 square foot deck area. The total project cost $5,664,000, including $1,480,000 of post-tensioning. 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-tensionsed strands. The main arches frame into massive thrust blocks using post-tensioned bars. The jury noted that the post-tensioned splice girders enabled quick construction -- an elegant solution for a relatively short span bridge. Further, the jury found this structure to be a good example of combining the segmental arch with splice girder design. Other members of the team include:
Engineer: DLZ Ohio, Inc.
Contractor: Kokosing Construction Company, Inc.
Other contributors: Finley-McNary (now Parsons), consultant to DLZ; Richard Goettie Company, subcontractor to Kokosing; United Precast, Inc., fabricator/supplier
About Post-Tensioning
Post-tensioning is a method of reinforcing and prestressing concrete, masonry and other structural elements. Simply, concrete and masonry are very strong in compression but relatively weak in tension. In comparison, steel is very strong in tension. Combining steel with concrete or masonry therefore results in a product that can resist both compressive and tensile forces. Further, if concrete is prestressed or "squeezed together" with the help of the steel (known as prestressing steel) during the construction phase, its resistance to cracking increases significantly.
There are two methods of prestressing: pre-tensioning and post-tensioning. In pre-tensioning, the prestressing steel is stressed at a precast manufacturing facility before the concrete is cast. With unbonded post-tensioning, the prestressing steel is installed on the job site just before concrete is poured. The prestressing steel is greased and encased in an extruded plastic sheathing to prevent it from bonding to the concrete. After the concrete hardens, the prestressing steel is gripped at both ends, tensioned and anchored to prestress the concrete.
About PTI
The Post-Tensioning Institute, a nonprofit association with more than 700 members worldwide, represents a community of businesses and professionals dedicated to expanding quality post-tensioning applications through research, education, code development and marketing. PTI conducts a bi-annual awards program to honor and recognize outstanding post-tensioning projects in the construction industry. Entries are received from around the world, and the winning projects are honored at the annual PTI Awards Dinner and Reception at each PTI Convention. For additional information, please visit www.post-tensioning.org.
About VSL
VSL -- a wholly owned subsidiary of Structural Group -- is the technical leader in the design, manufacture and installation of post-tensioning systems and components for the construction industry. As one of the nation's leading specialty contractors, Structural Group is comprised of three dynamic and diversified companies. Structural Preservation Systems is the largest specialty contractor focusing on structural repair and strengthening. VSL is the technical leader in post-tensioning and specialty reinforcement. And, Pullman Power leads the industry in chimney, silo, and stack construction, maintenance, and repair. From 20 operating centers around the United States, Structural Group businesses perform a wide range of projects involving industrial facilities, commercial properties, public infrastructure and municipal buildings. For more information about Structural Group, please visit http://www.structural.net/.