The Post-Tensioning Institute (PTI) recently honored VSL a nationwide specialty-construction company that designs, manufactures, and installs concrete
The Post-Tensioning Institute (PTI) recently honored VSL Û a nationwide specialty-construction company that designs, manufactures, and installs concrete reinforcement systems Û with three awards in for post-tensioning projects. Accordingly, VSL received PTI’s Award of Excellence: Parking Structures for the Union Station parking garage expansion project in Washington, D.C.; Award of Merit: Repair, Rehabilitation and Strengthening for the LeJeune Road Flyover in Miami, Fla.; and, Award of Merit: Bridges for the Siebenthaler Avenue Bridge project in Dayton, Ohio. As 2006 marks the company’s 50th anniversary in the U.S., VSL President Scott Greenhaus notes the timeliness of winning the PTI awards.
Judges for the biennial program evaluate submittals on creativity, innovation, cost effectiveness, functionality, constructability and aesthetics. Projects can be entered in seven categories including buildings, parking structures, slab-on-ground, strengthening/rehabilitation, bridges, industrial/special applications and international.
AWARD OF MERIT: BRIDGES
Siebenthaler Avenue Bridge
Constructed in 2002 through 2004 to replace an older deteriorating structure, the bridge was designed for a service life of 75-plus years, carrying vehicular traffic over a river, as well as bicycles and pedestrians on a bikeway and sidewalk, respectively. The 263-ft.-long Siebenthaler Bridge features a 15,780-sq.-ft. deck area and four precast, post-tensioned arches. Total project cost was $5,664,000, including $1,480,000 for post-tensioning.
The arch motif was chosen to complement other bridges in the city, and the segmental arches were shaped and sized to accommodate shipping and lifting logistics. Four main arches comprise three precast segments each, 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 Û an elegant solution for a relatively short span bridge. The structure was cited as a good example of combining the segmental arch with splice girder design.
Additional project principals
Engineer: DLZ Ohio, Inc.
Contractor: Kokosing Construction Company, Inc.
Concrete supplier: United Precast, Inc.
Other contributors: Finley-McNary (now Parsons), consultant to DLZ; Richard Goettie Co., subcontractor to Kokosing
AWARD OF MERIT: REPAIR, REHABILITATION AND STRENGTHENING
LeJeune Road Flyover
To help ease traffic congestion exiting the Miami International Airport, the Florida Department of Transportation opted to construct the LeJeune Flyover, a bridge that connects LeJeune Road to Okeechobee Road. The total project price tag was more than $14 million, including an unseen repair costing $425,000 in VSL post-tensioning.
Designed to carry two lanes of vehicular traffic, the 33-ft.-wide, 262-ft.-long, flyover superstructure is supported on two piers and consists of a twin, steel box-girder bridge featuring an 8-in., cast-in-place composite deck. Pier Two, whose cantilevered arm gives the pier an L-shape, is set on a below-grade footing. The second pier, Pier Three, is a hammerhead, T-shaped structure.
During initial construction of the three-span bridge over LeJeune, cracks were noted in two piers before the project opened to traffic. For a service life of at least 75 years, the Florida Department of Transportation required a crack-repair solution that would be durable, cost-effective and aesthetically pleasing. Further, the bridge was located over a canal, so the structure and repair needed to be resistant to corrosion from natural elements. An innovative turnkey repair and post-tensioned strengthening solution for the pier caps and columns was completed in four weeks.
The LeJeune Road Flyover repair project was commended by the jury for its use of post-tensioning as an economical solution to rehabilitate the structure with the least amount of disruption to traffic. Extra measures like HDPE ducts and high-performance grouts ensured that the repair was durable.
Additional project principals
Engineer: Keith and Schnars
Contractor: MCM Corporation
Concrete supplier: Rinker
Other contributors: Williams Form Engineering
AWARD OF EXCELLENCE: PARKING STRUCTURES
Union Station parking garage expansion
Originally built in 1908, Union Station is an architectural and historic landmark recognized as one of the busiest rail hubs in the country. Today, accommodating more than 20 million people annually, it is one of the area’s most popular tourist destinations featuring Amtrak, commuter and subway train service, plus upscale shops and restaurants. 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 covering 295,000 square feet cost $38 million, including more than $1 million of post-tensioning supplied by VSL.
As the expansion called for wide areas uninterrupted by columns, 98-ft. spans were achieved with post-tensioned concrete girders constructed monolithically using a beam-and-slab system. Advantages of post-tensioned concrete over steel trusses, according to project engineers, included a more durable, maintenance-free structure requiring no additional spray-on fireproofing. A bonded system was selected in order to reduce the quantity of mild reinforcement in the girders, thus minimizing congestion and saving time and money.
The Union Station parking garage expansion was recognized by the jury especially for its efficient use of lightweight concrete and post-tensioning to allow construction of an additional floor with the existing foundations. Using bonded as well as unbonded tendons also optimized performance of the structure. Additionally, the jury noted that designers avoided a separate transfer system by means of post-tensioning.
Additional project principals:
Architect: Tim Haahs and Associates
Engineer: Tim Haahs and Associates
Contractor: Clark Concrete Contractors LLC