A bridge replacement project near the Pittsburgh, Pa., Zoo and PPG Aquarium is well on the way toward its scheduled opening date of October 1.
Heth’s Run Bridge replacement project near the Pittsburgh, Pa., Zoo and PPG Aquarium is well on the way toward its scheduled opening date of October 1. The 100-year-old bridge was reportedly crumbling and in need of replacement. It carried 26,722 cars each day through Butler Street.
According to Dan Cessna of the Pennsylvania Department of Transportation (PennDOT), the new four-lane bridge is meant to mimic the architecture of the 100-year-old bridge it’s replacing, and has been in development for a decade.
PennDOT awarded the contract of $14.9 million to Trumbull Corporation, under the direction of Mehmet Akinci. Work began on Sept. 5, 2013, and full completion is set for Dec. 8.
The project covers the replacement of the existing bridge structure with a new single span structure, minor roadway re-alignment of the east approach, traffic signal improvements, drainage installation and other miscellaneous construction.
“We’re stepping back in time 60 or 70 years to imagine what the bridge was like in its grand days,” said Steve Cowan, PennDOT press officer.
The bridge was originally part of the northern entrance to Highland Park and the Pittsburgh Zoo, and was a simple concrete arch, with two arch ribs each holding 11 vertical spandrels. False quoins were molded into the corners of the abutments.
The deck, by popular area architect Stanley L. Roush, was made of white limestone in the form of some 360 carved balusters with 14 urns decorating the balustrades. All of the carved pieces along the southern side of the bridge were reportedly removed in the 1970s and 80s and replaced with aluminum railing. The northern balustrade remained, but large sections crumbled and fell into the ravine of Heth’s Run. Missing sections were patched with wood and metal scraps.
Over the years, the city filled in a 75-ft. (23 m) ravine under the bridge with rubble, blocking access to the river. The project will open access to the Allegheny River and enable planning for a grand entrance to the zoo and Highland Park.
When the work is completed, the city reportedly plans to rehabilitate about one-third of the zoo parking lot near Butler Street, creating a greenway with an athletic field, bike and walking paths connecting East End neighborhoods to the river, and a deck overlooking the river and Highland Park Locks and Dam.
The bridge project calls for building a temporary roadway through the zoo parking lot while the bridge is replaced.
According to Randy Burgard, PennDOT’s construction project manager, challenges include bulk residual waste removal, locating the existing storm and sanitary systems that were approximately 50 ft. (15.2 m) deep, installing manholes onto the sanitary and storm lines and the jack and bore process for a 60-in. (152.4 cm) storm line under the existing railroad tracks.
“The project is a 215-foot single span bridge,” Burgard said. “Several decorative elements such as quoins and precast urns and balusters are being used for the bridge. A total of 48,871 tons of bulk residual waste will be removed from the site.”
Major subcontractors include Bruce-Merrilees Electric, New Castle, Pa., for lighting and signals; Moretrench American Corporation, Rockaway, N.J., for micro-piles; Amelie Construction & Supply LLC, Saxonburg, Pa., for steel erection; and Pittsburgh Demo, Oakmont, Pa., for demolition.
Major equipment used in the job includes a Liebherr LTM 1250-6.1 crane, a Grove GMK525OL crane, a Caterpillar 320CL excavator, and a Hyundai R35Z-9 excavator.