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| The Walsh Group posted The arches turn pink for the National Cherry Blossom Festival! |
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| Photo by Brian Adler via Bridge Hunter, cropped, License: Public domain: Released by author [A rare girder-based swing span on the right side.] |
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| NewFrederickDouglassBridge, cropped |
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| Satellite The arches are done and they have started adding the deck modules in this capture. We can also see the temporary trestle they built instead of using cranes on barges. |
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| WorldHighways via Nathan Holth's comment on BridgeHunter The novel V-pier forms are designed to sit on the piers and are being moved into place using a self-propelled modular transporter. The 2008 refurbishment was extensive and it was to provide another 20 years of life, but it didn't. Work to replace the bridge started in 2017. The two piers rest on piles to reduce the amount of riverbed that must be removed because it is contaminated and had to be properly disposed of. Also, the piles, with great care, can dodge "old but important sewer lines." |
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| ASCE The Frederick Douglass Memorial Bridge is part of a $441 million project to improve transportation access in the rapidly developing southern end of Washington. (Photograph courtesy of District Department of Transportation) "Unlike the old bridge, the new bridge is not movable. DDOT conducted a study to determine the current and planned navigation along the Anacostia River, including the navigation needs of the U.S. Navy. The study, according to the department, 'determined that 99.8% of the current and projected vessel traffic on the Anacostia River could be accommodated by a fixed bridge with 42 ft of vertical clearance.' " [But what is supposed to happen when those 0.2% ships need to get through?] |
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| Screenshot @ 0:21 Note the cute little potted pine tree on top of the arch segment. |
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| Screenshot @ 1:25 Why did they use falsework on the left side of the arch but tie-backs on the right side? I would have expected a symmetrical solution. Is falsework cheaper but it would interfere with starting the installation of the deck on the right side. |
In the above screenshot, you can see the grey concrete piers at the bottom of the arches and the white steel segments between the arches. The piers were built with a cast-in-place method. The V-shape of the piers means a lot of the concrete in the piers was poured on an angle. The concrete that was on an angle proved to be difficult to access for vibratory consolidation. "Workers thus had to vibrate the concrete very exactingly — and they couldn't place it too fast or too slowly. Some concrete spalling on the first pier placement sent workers back to check the mix design, the rate of placement, how fast they were vibrating the concrete, and how they were curing it. As they were placing concrete, small samples could be tested; if there was a problem, engineers would let the concrete set, saw-cut and remove bad portions, and then recast. The work took 2-3 months, and many of the placements took place at night with concrete trucks operating from one of the lanes of the original bridge, which had been closed. Initially a standard concrete mix was used for the placements, but the mix design was revised to a “self-consolidating” mix to improve workability and reduce the need for access to vibratory consolidation, which greatly improved the concrete finish in these large intricate piers." [ASCE]
All of the concept art I saw had a bunch of fancy buildings along the river. This is one example.
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| ArchitectMagazine |
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