PennDOT's plans to repair I-95 go far beyond today's emergency work around a single cracked column.

The installation of support towers and beams should allow the road to reopen tonight, but that's a temporary solution, according to PennDOT spokesman Eugene Blaum.

The next step, which could take a month, will be to repair or replace the cracked column itself, he said.

But then comes the really major work: Replacing the whole elevated stretch of I-95 between Spring Garden Street and Cottman Avenue.

The stretch north of Cottman was replaced about five years ago.

This new series of projects, expected to take five years to complete, has been in the works for some time, Blaum said.

The cracked column may be an unsual case - it's the only one inspectors have found, Baum said - but it's evidence that construction has a lifespan.

"This whole section dates back to the mid 1960s," he said. "It's 40 year-plus in age, and it needs work."

While the superstructure, including the roadway itself, is rated a 5, or fair to good, the substructure of piers and other support components grades out at just a 4, making it considered deficient, he said.

The work, expected to begin by early next year, will be staggered and managed so that three lanes will remain open in both directions at all times, said Charles Davies, assistant district engineer for design in PennDot's Southeastern District.

Delaware Avenue and Richmond Street in Port Richmond will also get refurbished and realigned as part of the project, he said.

Gov. Rendell, at the worksite under the highway yesterday with Mayor Nutter, used the opportunity to press support for his $1.2 billion borrowing plan for the state's aging bridges, which include the elevated sections of I-95.

He said a "massive, stepped-up federal commitment" was needed to support infrastructure repair and renovation.

It will cost about $6 billion to modernize I-95 in Southeastern Pennsylvania, and Rendell said neither the city nor state could handle the tab.

"This corridor is crucial to the economic well-being and quality of life in the city of Philadelphia," he said.

Overnight, workers began installing four support towers brought in from Baltimore, Pittsburgh, Scranton and Coatesville, placing them around the compromised column.

Each of these open structures has four steel columns at their corners with connecting braces.

By 7 a.m., a huge metal "jacking beam" was put across two of the towers, on one side of the column.

After the second beam is in place, "there is a considerable bracing work that needs to be done and the jacking pads are to be installed this afternoon," Baum said.

But he expected the road to reopen tonight.

The chain of events leading to the latest shutdown was triggered Monday afternoon when Peter Kim, an engineering consultant for PennDOT, inspected a center support pillar near Cambria Street.

He found that a crack that had been about a half-inch wide and four feet long in 2005, and two inches wide in October, had become an 8-foot-long gash ranging in width to 2.5 inches to 5.5 inches and exposing rusted steel rebar, officials said.

PennDot Commissioner Allen Biehler said that the pillar had been earmarked for repairs this summer after the October inspection but that "rapid erosion" opened it more. PennDot engineer Harold Windisch said rusting metal, which expands, created an "abrupt reaction."

Two hours after Kim's discovery, PennDot's regional executive, Lester Toaso, decided to close the highway after conferring with department engineers and officials in Harrisburg.

"We were looking at the safety factor," said Toaso, who stressed that the pillar was not in danger of imminent collapse.

During the next five hours, PennDot officials notified states and transportation agencies along the I-95 corridor of the planned shutdown, and worked with city and state police and the Fire Department on closing the highway at midnight.