Pittsburgh's New Fern Hollow Bridge Nears Opening: CEG

Pittsburgh’s New Fern Hollow Bridge Nears Opening: CEG

The bridge is scheduled to open earlier than the tip of the yr and absolutely full the mission later in 2023. (Picture courtesy of Robert M. Byrnes, PennDOT)

The Pennsylvania Division of Transportation (PennDOT) continues to open a brand new bridge on the Fern Hole Bridge website in Pittsburgh, Pennsylvania, lower than a yr after it collapsed.

The bridge over Forbes Avenue between Squirrel Hill and Level Breeze collapsed on January 28, 2022. Underneath a $25.3 million emergency grant from the Federal Division of Transportation, PennDOT started work on January 3 february. The contract was awarded to Elegant building underneath the route of Pete Douglas. It’s deliberate to open the bridge earlier than the tip of the yr and to totally full the mission later in 2023.

The contract contains the demolition of the bridge collapse in addition to the design and building of the brand new bridge.

Doug Thompson, senior assistant building engineer, PennDOT District 11, stated early on PennDOT supplied to assist town and supply experience.

“I assume they made a authorized settlement within the early days with town in order that PennDOT might take over the design and building obligations for the mission, to interchange the bridge,” he stated.

Jason Zang, assistant district supervisor, building, PennDOT District 11, stated they’re additionally speaking carefully with FHWA about how they’ll proceed as shortly as attainable.

“They principally stated what you wished to do is choose a contractor and that is how we did it,” he stated. “So we picked a contractor and we picked a consulting agency proper off the bat and that was, I feel, day one or day two. That was proper after the collapse. In all districts of PennDOT, the principle perform is to place tasks out to tender so it is sort of our specialty to get tasks out to contract and tender None of us wish to see that in our careers and I hope we do not. “We’ll by no means need to see it once more, however this bridge carries about 20,000 automobiles a day, I feel. The purpose was to interchange the bridge as shortly as attainable. That is at all times been the purpose.”

Thompson reported in late September that the collapse was first cleaned up, restored, and wasted, and concurrent design and building started.

“In reality, the design began a few month earlier than we might begin building as a result of we needed to put together plans for the foundations, so proper from the beginning they did surveys and began designing their foundations,” stated he declared. “Fairly shortly we narrowed down the kind of building. We principally discovered the width of the bridge – the bridge needed to be the identical one which was there now due to the appropriate of method town had by a park and all the pieces.”

As soon as the span configuration was decided, the contractor labored shortly to find out the kind of construction obtainable most shortly: metal or concrete. Primarily based on value and availability, prestressed concrete I-beams have been chosen.

“The figuring out issue within the timing was when the beams could possibly be delivered,” Zang stated. “We took that date based mostly on when the beams could possibly be delivered and we moved again to April…so we weren’t on the market simply wading round. We wished to be environment friendly, so there was a time when there was no there wasn’t a lot”

Because the girders have been constructed, the designers finalized the columns and headers above the caisson foundations and designed the abutments. Beams began arriving on July 25.

“There have been challenges related to that,” Zang stated. “They might ship two beams a day. As soon as they bought to Pittsburgh, town coordinated and escorted the beams by congested areas of Oakland. Oakland is a fairly busy space, in order that they escorted the beams by Oakland, we introduced them in and erected two a day for the primary two spans. So we had the primary 14 beams erected, two a day, after which they introduced in span three from a unique route, not by Pittsburgh however from east facet of Pittsburgh by Monroeville they usually backed them up. It bought quite a lot of consideration once they closed off the road and backed them as much as Braddock Avenue and onto the location.

Then the contractor organized for the rental of two giant crawler cranes to erect the beams. The biggest was delivered with over 50 semi-trailer hundreds and the opposite with 25 semi-trailer hundreds.

“They erected the Span 2 girders with the massive crane that sat on the abutment,” Thompson stated. “They erected these Span 2 beams on Span One, after which the following day that they had a smaller crane, though it was a really giant crane. They usually had a smaller crane sitting within the valley. Then they did a two-crane carry – a double lifter – and a crane picked up both finish of it as she sat on span 1. Then they each lifted her into place within the span 2 as a result of there was merely no crane obtainable with the radius and skill to carry the beam from behind the abutment clear to the middle span.”

As for the challenges, Thompson talked in regards to the effort it takes to shortly and concurrently design and construct a bridge and actually begin building once you solely have the muse plan to show.

“One other nice problem that I personally took on, like Jason [Zang] stated earlier, we’re actually good at creating designs and making ready a young doc and placing tasks out to competitors and contractors bidding on a mission and giving us a worth for a bridge,” he stated. declared. ” However [with] this one, there was nothing to bid.”

As a substitute, the contractor and designer have been chosen after which costs have been negotiated. Throughout the design of the bridge, the muse plans have been accepted, so the price was negotiated.

“We have been negotiating the price piece by piece, which is fairly robust, however we’re getting by,” Thompson stated.

On the design facet, he famous that PennDOT design mission managers went by the method on a really accelerated schedule.

“Hats off to the designers,” stated Thompson. “We nonetheless need to undergo all design processes although there are contingency procedures in place. In order that they’ve accomplished an awesome job of doing what they’ll to make sure the general public continues to be concerned in all processes. environmental points and getting some public involvement on the creative facets of the bridge. It is onerous to get public enter shortly whereas speeding to construct the bridge.”

Working with utilities has additionally been a course of, together with relocation and a 16-in. gasoline line that was severed throughout the collapse.

One other problem famous by Thompson was defending what is called “the gatehouse,” a historic stone lodge construction simply across the nook from the bridge.

“We needed to discover a approach to defend that whereas we have been digging,” he stated. “This gatehouse was a problem that we took on.”

The construction was 2 toes from vertical building and a brief shoring wall was in-built entrance.

Thompson reported that plans name for incorporating a polyester polymer concrete liner into the mission to guard the concrete. It is one thing new in Pennsylvania.

He additionally famous that the columns of the bridge can have formwork liners to make them seem like the reduce sandstone on the unique bridge basis. They are going to be coloured to match among the present sandstone abutments which have been retained on the bridge.

“We seemed round to see what facets of the previous bridge we wished to attempt to go away, just like the previous abutments simply to possibly inform the story of what was there up to now,” Thompson stated. . “We determined to go away the previous Okay-frame foundations in place as properly and thought somebody would possibly wish to attempt to put a plaque or one thing and inform the story of the bridge collapsing and have these previous foundations there doubtlessly for this use.”

One of many greatest challenges, in line with Zang, was merely the high-profile nature of the mission.

“As a result of the bridge collapsed and it bought nationwide consideration; it was the day President Biden was in Pittsburgh,” he stated. “So…everyone seems to be watching and we have been very cautious and really cautious with what we are saying to the general public. We’re watching the schedule very carefully and the crew has labored actually onerous. All of it overlaps. It is utterly totally different to what which we normally do in Pennsylvania and it permits the mission to go lots quicker as a result of you have got the development happening whereas the design is occurring. It isn’t linear like all the opposite tasks.

Small tools reminiscent of excavators, bulldozers and small cranes are owned by the contractor, however giant cranes have been leased.

The first contractors for the mission are PENNSTRESS of Roaring Springs, Pennsylvania; Weatherspoon and Williams LLC of Coraopolis, Pennsylvania, for the beams; Corridor Industries, Elwood Metropolis, Pennsylvania, for the bridge railing; and HDR of Pittsburgh, Pennsylvania, for the design.

The brand new bridge is 21 girders, 150 toes lengthy and roughly 8 toes excessive and over 1,000 cu. yards. of concrete on the deck. The bridge is 100 toes excessive above the path.

Site visitors was rerouted on the day of the collapse and remained so all through the mission. This additionally contains pedestrians within the space. CEG

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