The 2,000 foot long and 301 foot high Kinzua Viaduct once held the distinction of being the longest and tallest railroad viaduct in the world. It was built in 1882, and eventually became registered as a national civil engineering historic landmark and remained a notable tourist attraction that contributed to the local economy.
Under a five-year open-end contract to complete NBIS inspections of Department of Conservation and Natural Resources (DCNR)-owned bridges, HRG inspected this viaduct, and recommended it be closed in 2002 due to significant deterioration. The inspection revealed that the deterioration to the tower columns and anchor system made it susceptible to high winds. An emergency design-build rehabilitation project was implemented in 2003, but with only half of the structure repairs completed, the viaduct was struck by an F1 tornado on July 21, 2003 and the unrepaired portions of the structure collapsed.
After conducting a feasibility study, it was determined that it could cost upwards of $45 million to rebuild the structure. Therefore, the best option for preserving this once considered “eighth wonder of the world” would be to repair and stabilize the remaining towers and build a $4.3 million unique tourist attraction known as the Kinzua Sky Walk.
Overcoming accessibility and constructability challenges due to the project’s unique location, officials, contractors and HRG’s team of engineers, championed the restoration of the damaged structure to safely support pedestrian access and encourage increased tourism to the site. The Sky Walk is 600 feet long and 225 feet high with a steel framed, octagon observation deck with a glass floor (similar to the Grand Canyon Sky Walk) at its center. The glass allows visitors to stand and peer beneath their feet at the tower’s unique rigid frame construction and view the vastness of the gorge below and gain a glimpse of the devastation caused by the F1 tornado.
The repairs were carefully designed to be a seamless extension of the original railroad viaduct, not distracting from its original character and impressive appearance. Replacement components were fabricated as an exact match to original components based on the plans obtained from the Smithsonian Institution. A588 weathering steel was also specified to match the 130-year old unpainted steel. The original track rails were reinstalled and wood walkways lead visitors to the observation platform and glass floor at the end of the Sky Walk. An ADA pathway leads to the Sky Walk, providing access to this majestic panoramic view.
The project was completed in the fall of 2011 and was recognized with Engineering News-Record’s prestigious 2012 Mid-Atlantic’s Best Project award in the small projects under $10 million category for best achievement in design and construction.
Video: Tracks Across the Sky
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