One of the most complex bridge construction projects to occur locally is well past the two-thirds mark in completion.

Four bridges on the Northeast Extension of the Pennsylvania in the vicinity of Parryville have taken shape. Two of the four spans are nearly completed and are expected to be open for traffic by next Spring.Tony DiVirgilio, resident engineer for Urban Engineers of Philadelphia, said the project, which began two years ago, is still on schedule. He said the southbound lanes on the bridges will be opened in spring, and the northbound lanes will open in the fall - all with virtually no inconvenience or interruption to motorists.DiVirgilio, who drives to the project site daily from his home in Media, doesn't mind the commute."The complexity of the job and the size of the job; as an engineer, it's been impressive for me," he said.He credits "a good contractor - Walsh Construction Group of Chicago" - for the project's smooth progress.Most of the construction work is suspended for the winter months because concrete doesn't cure properly in the cold temperatures, reducing the strength and durability of the pavement. When construction resumes, the remainder of the work to construct the southern transition will be completed.DiVirgilio pointed out some of the interesting features of the project, including:• Two of the bridges span the Pohopoco Creek and two are over the Lehigh River. Each are two-lane widths and handle single-direction traffic.• The bridges consist of concrete beams that are pre-cast Bulb T, and are 11 1/2 feet in diameter at the bottom and diminish in width to 7 1/2 feet at the top.• Concrete to construct the bridges was purchased from Rock Hill Industries of Parryville, which is located directly beneath the Lehigh River project.• The bridges over the Pohopoco Creek are 120 feet high and 800-feet in length, while the Lehigh River bridges are 80 feet above the river and 1,200 feet long.• The crane used for the project has 300-feet of boom. Attached was an 11 1/2 foot diameter drill shaft, the largest such caisson used in Pa. It took two weeks to disassemble and relocate the crane each time it had to be moved.• Excavation was made into about 100 feet of the base of the mountain on the south side of the Lehigh River Bridge.• There was 850,000 cubic yards of excavation on the job. Put in perspective, a typical construction truck holds about 20 cubic yards of material. Some of the material excavated was utilized by Wal-Mart for its project in Mahoning Township.The four bridges replace two spans which were constructed in 1954.Besides the new bridges, Walsh Construction also had to build temporary spans over Pohopoco Creek and the Lehigh Canal for moving construction equipment. DiVirgilio said the construction contract mandates the removal of these smaller bridges even though some people have asked that they remain.Mimi Doyle, public information specialist for the Pa. Turnpike Commission who accompanied the TIMES NEWS on a tour of the construction project, said numerous engineers have visited the site because of their interest in the complex project. In addition, geology students have sought permission to look for fossils on the excavation site.The project, which cost $101.5-million, is part of the self-funded, capital improvement plan of the Turnpike. Construction on the bridge project began Dec. 22, 2008.DiVirgilio said besides the monumental physical construction, there were stringent ecological and historical restrictions, including the Lehigh Canal and related walkways.There were small areas of wetlands moderately impacted, but these will be restored or replaced.Doyle has been making regular visits to the construction site from her Philadelphia office and keeping a photographic chronology of it."It's incredible to be able to see the progress," she said, recalling her first visit before any piers were built.She said she couldn't even envision the location of the finished bridges, but now that the spans are nearly finished, she's amazed at the amount of work it involved."To see how much rock slope was taken back and where the road is located has been interesting," she added.The new bridges run parallel to the existing spans. The piers for the original bridges show excessive deterioration.After the new bridges are operational, the project still won't be deemed complete. In 2012, Walsh Construction will construct a hiking trail, wetland mitigation site, and causeways for bridge demolition, and then demolish the existing bridges.DiVirgilio said he has had numerous requests for tours of the construction project by the media, engineers, and government officials, but doesn't mind."I enjoy taking people on tours. I like to show the job off," he said.