Murrysville could abandon sinking Twin Oaks Drive
After an engineer told them that Twin Oaks Drive isn’t going to stop moving anytime soon, Murrysville officials are considering abandoning of the collapsed section of the road.
Consulting engineer Joe Dietrick of the Greensburg-based Markosky Group last week told officials the section of Twin Oaks Drive in central Murrysville — which initially collapsed in April 2013 — continues to worsen into “a major-league landslide.”
“We’ve had a lot of experience with slides,” he said. “I’ve never seen one like this.”
A roughly 180-foot section of the road was part of the original collapse. Dietrick said municipal crews were able to dig down 15 feet on either side of the road without hitting rock. From a foundation perspective, that’s bad news.
“The material underneath the buckled portion of the road is very poor,” Dietrick said. “We also discovered that there was an earlier landslide on the upper portion of the road in 1980.”
The buckle is along a stretch of Twin Oaks Drive that is in close proximity to Acorn Lane and Twin Oaks’ northern intersection with Sardis Road. Twin Oaks runs parallel to Sardis in central Murrysville and reconnects with it near the Sardis-Mamont Road intersection.
Dietrick said the area has a prevalence of “Pittsburgh red beds” — a layer of red shale and claystone that has been the culprit behind a number of Pittsburgh-area landslides over the years. The soil composition and the introduction of water, Dietrick said, are the primary reasons for the collapse.
Dietrick said two possible solutions could prove expensive.
“A retaining wall would be very expensive,” Dietrick said. “We could also remove all of the bad material — about 9,500 cubic yards worth — and backfill it with rock. That could potentially cost about a half-million dollars.”
Morrison said he plans to ask for council’s approval to create cul-de-sacs on both sides of the slide and essentially abandon the collapsed portion of the road.
“We just don’t believe a half-million dollars is worth it for this stretch of road,” Morrison said.
Councilman David Perry said if the choice is to create a double cul-de-sac, officials need to investigate what will happen to the municipal right of way if there is a need to restore Twin Oaks Drive in the future.
An attorney representing residents Jan and Jeanine Seski, who live on the 4000 block Twin Oaks Drive and are among the most-affected by the collapse, asked that his clients be kept in the loop as a decision is made about the road.
Patrick Varine is a staff writer for Trib Total Media. He can be reached at 412-871-2365 or firstname.lastname@example.org.