When planners and engineers first looked at building a taller and wider bridge next to the existing Gerald Desmond Bridge, one priority during construction was to keep traffic moving in and out of one of the world’s busiest port complexes.
The existing Gerald Desmond Bridge would remain open until the new bridge was completed. However, new-bridge construction would take a few years and require the demolition of freeway on-ramps, off-ramps and connectors. Traffic patterns along bridge routes and within the Port facility would be realigned several times.
Before construction began, engineers and designers laid out on maps a series of new roads and ramps, intricate detour routes and timetables. Detailed blueprints carefully planned the timing and phasing of detours, including a re-routing of train tracks. Building deep foundations and massive new bridge columns in tight spaces next to the existing Gerald Desmond Bridge would mean relocating surface streets within the Port of Long Beach and guiding commuters along new paths.
With these detailed and often thick master documents, the construction team met weekly with staff from the Port of Long Beach and its building partner – Caltrans – to further plan each and every upcoming road closure and detour. The phasing and timing of road closures and detours were carefully planned to ensure two critical things: Crews could keep building foundations, columns and towers to keep the new bridge project on its timetable while Port traffic would remain disrupted as little as possible.
On Monday, June 11, the last major detour will commence with the closure of the connector ramp from eastbound Ocean Boulevard to the northbound I-710. The ramp will be demolished as part of the Gerald Desmond Bridge Replacement Project to enable construction of a new ramp. The detour will briefly send traffic onto surface streets before rejoining the northbound 710 Freeway.
“We’re into the home stretch of the new bridge project,” said Duane Kenagy, Interim Deputy Executive Director of the Port of Long Beach. “This detour will be the last big one before we begin connecting the ends of the new bridge to existing highways. We are very pleased with the outcomes of all our traffic planning – the cargo continues to flow.”
Cables being attached
Some call it a daily “high-wire” act.
With the two 515-foot-tall towers completed, construction crews are now lifting massive steel beams into place to build the center span portion of the new bridge. Holding the superstructure in place involves connecting massive cables from the tower to the steel frame. Unlike suspension bridges, which anchor cables at either end of a bridge and “drape” them over towers, a cable-stayed bridge supports the road with cables fanning out from the tops of towers, which bear the weight of the roadway.
The first sections of the center span are built around each tower and will extend outward in equal, balanced portions. As each new section of steel is put into place, cables will be lowered from the tower and attached. Pre-cast concrete panels are laid on top of the steel and will form the main roadway.
About 200 feet above seawater, workers in this area of the bridge are not the only ones performing a high-wire act. Work is spread out along the entire 1-mile stretch. Some construction workers are perched nearly 180 feet up, atop massive machines used to build steel-reinforced elevated roadways called “approaches.” These machines, called movable scaffolding systems, are clamped onto bridge columns and provide a safe platform to lay in steel and concrete. As each 250-foot section of new road is completed, the machines then begin a slow traverse to re-attach to the next set of columns to begin the steel-and-concrete process again.
While these crews are up in the air, others are still “going deep,” drilling into the ground. With the demolition of the northbound 710 Freeway ramp, construction can now begin on the final set of deep piles that serve as the bridge’s foundation. Only about a dozen of the project’s 352 piles are left to build.
By the end of next year, everything will come together as a new, iconic 100-year bridge will be set to open.
To see live video of the bridge project and for other updates, visit: http://www.newgdbridge.com/.