Four new bridges crossing the Lehigh River and Pohopoco Creek recently opened to traffic, replacing two, deteriorating, 55-year-old original structures on the heavily traveled Northeast Extension (Interstate–476) of the Pennsylvania Turnpike between mileposts 72 and 74 in Carbon County.
Part of a Pennsylvania Turnpike Commission self-funded initiative to modernize 546 miles of aging highway, the $102 million construction project has provided an economic boost to the region, and positioned Northeastern Pennsylvania to compete for better jobs. Pennsylvania Turnpike Commission CEO, Roger Nutt, stated, “For the past three years, this toll-funded construction project has helped provide economic stimulus for the region’s workers and suppliers, directly employing as many as 250 men and women. As we celebrate the completion of these impressive structures, we are thrilled to deliver a major infrastructure enhancement for all those who use this stretch of the Turnpike for business, personal and vacation travel.”
Urban Engineers, Inc. (Urban) has been leading the construction management effort for this project since it broke ground in January 2009. Urban’s President and CEO, Edward M. D’Alba, PE, stated, “The new bridges make a bold and significant case for infrastructure investment. The crumbling, original structures are a stark contrast to the four new bridges now providing safer transportation for 30,000 vehicles per day and enhancing the region’s economic competitiveness. No one would want to imagine the negative economic impact if the original structures were not replaced.”
“This is one of the most significant projects in Carbon County in years, both from a transportation-safety and an economic-development standpoint,” Carbon County Commission Chairman, William J. O’Gurek, said. “This level of investment represents a shot in the arm for our economy, spurring spending by contractors for materials and equipment and by workers for meals, lodging, and other living expenses.”
The bridges – two north bound and two south bound – were erected parallel to the west of the existing bridges and equal about a mile of new bridge superstructure. The new spans rise to an impressive 120 feet above State Route 248, the historic Lehigh Canal, Norfolk-Southern Railroad tracks, and recreational trails, in addition to the waterways below.
“This was a monumental task,” the project’s Resident Engineer, Urban’s Aaron Barnes, PE, stated. “Enormous beams, with some exceeding 160 feet in length, eight-feet high and weighing over 200,000 pounds, are some of the longest and heaviest pre-stressed beams erected in the state. The bridge foundations utilized the installation of drilled shaft caisson construction, ranging from seven feet to 11 feet-six inches in diameter for the substructure, drilled 30 feet into bedrock – the largest that I have ever worked with.”
The final phase of construction will be the mechanical demolition (no blasting) of the two original bridges as well as removing the original roadway pavements. The demolition will generate approximately eight and a half million pounds of steel. Additionally, construction of wetlands, stream bank restoration and improvements to the multi-use trail along the Lehigh River and Canal, as well as other aspects of the project, will continue through the end of 2012.