McArdle Roadway, which leads up to Mt. Washington and had been closed following a landslide in early January, is now reopened after $1 million of reconstruction, but it will be closely checked during wet weather to prevent more problems.
Rob Kaczorowski, director of Public Works for the city of Pittsburgh, said he is confident the problem that led to more than 100 tons of earth sliding onto the roadway has been fixed.
"The big part was the drainage. We made sure drainage was part of the wall, part of securing the shell with the gunnite and actually down at the roadway itself," Kaczorowski said. "I think water was the major problem with the hillside, and we addressed that as well as securing the hillside."
Kaczorowski said monitoring will be done depending on the season. He expects weekly check-ups during rainy months and monthly check-ups in dry weather. He said the examinations will be done by department personnel.
"Unfortunately I don't think a computer will work as well as a human eye on this," Kaczorowski said. "We'll have our engineering staff go out and do our field investigations and monitor it that way."
Kaczorowski said there were multiple steps to repair the hillside and techniques used to prevent further problems. In the first phase, the workers grouted and filled in fractures in the shale rock, and installed a wall to solidify Grandview Avenue, which runs above the hillside. The second step included installation of a drainage system and securing the rock bed using a technique called "rock nailing." Finally, the team used gunnite, a concrete slurry material, to seal the exposed face of the shale rock to prevent future erosion of the hillside.
He said there should be no concern for a long time over the safety and strength of the hillside along the roadway.
"That section of roadway that we repaired, that will be stabilized well after I'm dead and gone," he said. "Other sections of the roadway I'm not too sure of, we'll just keep an eye on that and anything that needs attention, we'll address it."