For many years, PennDOT District 11 in the Pittsburgh region had been performing many inspections and repairs to a small structurally deficient bridge along Route 30 over Bessemer Avenue in East Pittsburgh Borough.
Constructed in 1930, the bridge was just miles from busy Interstate 376 and downtown Pittsburgh. Given the location's narrow urban corridor and high traffic volumes of about 22,000 vehicles a day, the district looked carefully at all options for replacing the structure. Neither a long-term full closure with a lengthy detour nor a long-term single lane restriction was desirable. Instead, the district determined that the structure was a good candidate for an Accelerated Bridge Construction (ABC) project, an innovation championed by the Pennsylvania State Transportation Innovation Council. To further accelerate, the district decided it should be replaced in a single weekend.
"The Department always considers ways to minimize the impacts construction has on motorists' commutes, especially in the heavily congested areas within our region," said District Executive Cheryl Moon-Sirianni. "Because we value our customers' lives and time, when cost effective, we use Accelerated Bridge Construction techniques to save months of lengthy detours and congestion."
The contract was awarded to Brayman Construction Corporation in November 2015. Crews worked over the winter and early spring prefabricating the various components needed for the planned ABC project scheduled for May 2016.
Crews went on site to demolish and replace the bridge structure in 57 hours. Despite rain through much of the weekend, crews were able to quickly finish the bridge replacement.
Beginning at 9 p.m. on the first night, a Friday, the bridge was closed, and by Saturday night the structure was demolished. From Saturday night through Sunday morning, crews set the new precast deck and the approach slabs panels. Then from Sunday afternoon through Monday morning, Ultra-High Performance Concrete (UHPC) was used to bond the individual pieces into a uniform structure. By 6 a.m. Monday morning, the bridge reopened to traffic.
Several factors allowed this bridge replacement to occur rapidly. The substructures were in good condition and were adequate to continue to carry the load of the new structure and traffic. The tops of the existing abutments were cut off and replaced with new precast caps. The deck was fabricated locally in Saxonburg, Pa., pre-assembled and then unassembled prior to being transported to the project location. Additionally, UHPC achieves high strengths in a very short time frame.
An additional weekend closure to place a latex overlay and conduct paving operations occurred two weeks later.
The photos below were taken during construction.