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Sections of the replacement for the Gerald Desmond Bridge have begun with a movable scaffolding that lays the concrete in sections Thursday, April 14, 2016, Long Beach, CA. Workers lay re-bar on top of plywood planks where the next section of bridge deck will be poured.
Sections of the replacement for the Gerald Desmond Bridge have begun with a movable scaffolding (the orange steel) that lays the concrete in sections Thursday, April 14, 2016, Long Beach, CA. The giant hydraulic lifts at the bottom move the form into place along the column.
Sections of the replacement for the Gerald Desmond Bridge have begun with a movable scaffolding that lays the concrete in sections Thursday, April 14, 2016, Long Beach, CA. Ramps from the old bridge are constantly being shifted as new columns for the new bridge are being built.
Work crews building the Gerald Desmond Bridge Replacement have been spending their days high above Terminal Island atop a gargantuan structure designed to provide form to the future roadway.
Called a self-launching movable scaffolding system, or MSS for short, the technology has never before been used to build a bridge in California, according to the project team. The system eliminates the need for workers to build wooden scaffolding systems to support the bridge structure so other tradesmen can place the concrete for a new roadway for truckers and other drivers travelling between downtown Long Beach and Terminal Island.
“The MSS is a good solution for not having to design the 150 feet of vertical pieces that all have to be bolted together,” senior engineer Zeph Varley said.
The first of two movable scaffolding systems — each with a price tag about $10 million and built from more than 3 million pounds of steel — is in place on Terminal Island, where workers are building the part of the new bridge designed to carry drivers traveling westbound, from downtown Long Beach to the island.
Port of Long Beach spokesman Lee Peterson said the second system, a blue one, will be used later in the year for construction on the eastern side of the bridge.
Plans call for the movable scaffolding systems, built specifically for the Gerald Desmond Bridge Replacement project, to be used to help crews build the elevated roadway segments leading to the replacement bridge’s main span, which is designed to cross a Port of Long Beach channel between Terminal Island and the rest of Long Beach with a 205-foot clearance for shipping vessels.
Construction crews have already used the movable scaffolding system to build the one segment of the replacement bridge, near the eastern end of the span where other workers use earth-moving equipment to build the new roadway needed to connect the replacement bridge to Terminal Island’s street network.
The project’s schedule calls for workers to conduct the precision work of pouring concrete for the next bridge segment on Saturday.
As of Thursday, the movable scaffolding system had made it possible for workers to assemble the formwork — think of it as being essentially a mold for construction concrete — necessary to accomplish that task. A garden of rebar was in place to strengthen the future structure and other workers had also installed the structure to hold steel tendons that Varley said will help the bridge support the weight of crossing traffic.
Skilled workers also can access areas below the bridge in order to use laser surveying equipment to ensure the scaffolding system — and segments of the future bridge — are properly aligned, Varley said. After the concrete for each segment has been placed and hardened, workers can lower the formwork and begin the job of extending the scaffolding system outward into space so crews can begin the next stage of the work.
A snail’s pace
As explained by project director Bill Corn of Shimmick Construction in a video showing how the system works, the MSS is anchored to columns supporting the elevated roadway. The scaffolding system can be moved about 235 feet outward from its starting position in order to allow construction crews to begin the next segment.
The project’s engineering and safety requirements mean the scaffolding system can only be moved about two feet at a time, Varley said. It takes about a day for the system to move the entire distance needed for workers finished with one segment to begin the next section.
“It’s like a snail,” Varley said.
He also said, however, that the having the systems at the job site may allow crews to have scaffolding in place in half the time that would be required using old-fashioned techniques.
That kind of old-school work, using wood, steel and other materials to create support structures known as falsework is being employed elsewhere at the job site, such as places where workers are building ramps to connect the new bridge’s roadway.
More work to be done
An entirely different engineering solution will be required to support the main span, Varley said.
The replacement bridge has been designed as a cable-stayed bridge, meaning that steel cables linking the main span to concrete towers will provide the support needed to keep the bridge in place.
Cable-stayed technology also will be required to support the main span during its construction, Varley said. “That’s next year’s story,” he said.
The Port of Long Beach and Caltrans are the key public agencies supporting the bridge project. L.A. Metro and U.S. Department of Transportation also have provided money for the project, according to officials.
A joint venture involving the firms of Shimmick Construction, FCC Construccion and Impreglio S.p.A. has the contract for the bridge. Shimmick is a California firm with offices in Irvine and Oakland. FCC and Impreglio are Spanish and Italian companies, respectively. The Gerald Desmond Bridge Replacement project has a budget of nearly $1.5 billion and is expected to be completed in 2018.
The project team plans to hold an open house in early May to provide a public update on the project.
The meeting is scheduled to take place from 7 to 9 a.m. May 4 at Hyatt Centric The Pike Long Beach, 285 Bay Street. Validated parking, breakfast and coffee will be available.
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