Liberty Tunnels to build on the past

A rendering of what the facades of the Liberty Tunnels will look like after a renovation project. Details have not yet been finalized, and the project's completion is scheduled for November 2013.

A continuing renovation project at the Liberty Tunnels will give its entry facades a new look that is actually quite old.

The fourth phase of work, scheduled to begin next year, will restore the facades to an appearance very similar to what graced the entrances when the tunnels opened in 1924.

"We're trying to replicate some of the original detailing," said Joseph DiFiore, area manager for Parsons Brinckerhoff, which is designing the project for the Pennsylvania Department of Transportation.

The original facings were concrete with "Liberty Tunnels" engraved on a beam above the portals. In the early 1970s, they were covered with skins made of COR-TEN steel, which develops a rust-colored patina, and brick walls. The steel skins were removed years ago so engineers could evaluate the condition of the concrete behind them.

The first phase of renovations in the 1.1-mile tunnels began in April 2008. PennDOT has invested about $23 million in the tunnels during the first three phases.

Much of the next phase, estimated to cost as much as $24 million, will involve removal and repair of deteriorated concrete, Mr. DiFiore said. When the steel skin was stripped away, about 2 feet of the 4-foot-thick concrete wall behind it was in poor shape, he said.

The project also calls for repairs to a 6-inch-thick curved concrete wall that creates a ventilation duct inside the tunnels, moving air to and from four ventilation shafts that rise 200 feet above the tunnels, connecting to a fan house in Mount Washington. The Liberty Tunnels are believed to be the first artificially ventilated highway tunnels in the U.S., he said.

The tunnel's 11 cross passages, spaced about 500 apart and designed to allow people to escape on foot from one tunnel to the other in an emergency, will be repaired, with new fire doors and new lighting.

The plans were displayed at an open house at Elizabeth Seton Center in Brookline last week.

Cheryl Moon-Sirianni, PennDOT assistant district executive for design, said traffic restrictions will occur mostly at night and on weekends, with some full weekend closures possible. Details have not been finalized. Completion is scheduled for November 2013.

After that, one phase of work remains. It will center on the fan house and is expected to have minimal traffic impact.

Jon Schmitz: jschmitz@post-gazette.com or 412-263-1868. Visit the PG's transportation blog, The Roundabout, at http://www.post-gazette.com/roundabout. Twitter: @pgtraffic.

First published on February 20, 2012 at 12:00 am

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Liberty Tunnels to build on the past