It has been 23 years since the city hung nets on the Greenfield Bridge over the Parkway East to catch debris crumbling from its underside, and a decade since it built a separate bridge-like structure over the parkway to catch whatever the nets missed.
Now, the days are numbered for what is regarded at best as a curiosity and at worst as a civic embarrassment.
The city will tear down and replace the 82-year-old bridge starting in 2015, a project that will require closing the parkway for several days and covering it with a 10-foot layer of dirt when what's left of the old bridge is dropped to the ground with explosives.
Residents of Greenfield and other affected neighborhoods got their first look at the project plans, and the considerable pain they will face when construction starts, at a meeting Wednesday at St. Rosalia Church.
"Unfortunately, the time has come when we have to say goodbye to this bridge," city public works director Rob Kaczorowski told more than 100 attendees.
The bridge is scheduled to close in October 2015, with the opening of the new $13 million span planned for May 2017. Some 8,000 vehicles a day, plus countless bus riders, pedestrians, bicyclists and joggers, will have to find alternate routes with the loss of a key connection between Greenfield and Oakland.
Sections of Pocusset Street and Greenfield Road on the Schenley Park side of the bridge also will be closed throughout the construction.
Patrick Hassett, assistant public works director for transportation and engineering, answered a question on the minds of many: Why not a less disruptive rehabilitation? That would cost as much as replacing the bridge, he said, but deliver about 30 years of useful life, while the new bridge is expected to last a century or more.
"While the bridge is safe and continues to be safe, the writing's on the wall," he said. "There's just not much left there to rehabilitate."
The new bridge will look similar in profile to the doomed one, but with steel arches rather than concrete. The ornate urns, pilasters and period lighting that were part of the old bridge will be restored on the new span, Mr. Hassett said.
The deck will be 5 feet wider, and two options for allocating the space are under consideration, both keeping the traffic configuration of two lanes toward Greenfield and one toward Schenley Park.
Option A would have sidewalks on both sides and 14-foot-wide curb lanes that would accommodate vehicles and bicycles. Option B eliminates the sidewalk on the side facing east and substitutes a dedicated bike lane. The west side would have a 14-foot shared lane.
When demolition begins, crews hope to dismantle most of the upper part of the bridge, leaving only the sweeping concrete arches. They will be wired with explosives and dropped to the parkway below, which will have been covered with 10 feet of dirt to absorb the impact.
That will be done in the week between Christmas 2015 and New Year's Day, fully closing the Parkway East to all traffic for several days. That week was chosen because that's when traffic volume is lightest, Mr. Hassett said.
Debris falling from the old bridge onto the parkway has been suspected as a cause of several accidents. In one incident in June 1990, there were 20 crashes and several injuries, but city officials contended that vandals threw the debris off the bridge.
A 10-inch chunk of concrete went through a car windshield in 2003, injuring the driver. Later that year the city spent $652,000 to build the temporary bridge to catch whatever came through the nets. Mr. Kaczorowski said periodic visual inspections are finding "nothing significant" on it.
Federal funding will pay 80 percent of the project cost. The state will cover 15 percent and the city 5 percent.
"I know this project's going to be an inconvenience for a lot of you," City Councilman Corey O'Connor told the audience before joking that hang-gliding across the chasm will not be allowed after the old bridge is down.mobilehome - homepage - neigh_city - Transportation
Jon Schmitz: firstname.lastname@example.org or 412-263-1868. First Published January 17, 2013 5:00 AM