1917: (Archived Bridge Hunter) This was the third bridge built at this crossing.
1991: (Archived Bridge Hunter; Satellite, it is the northern bridge) |
| Bridges Now and Then posted Seattle's Spokane Street Bridge, a double swing bridge, pretty neat, details in the comments. (Mark Yashinsky) Bridges Now and Then: https://en.wikipedia.org/wiki/Spokane_Street_Bridge The bridge on the right is the Seattle West Bridge or High Bridge. |
The two round piers are what allowed me to identify the swing spans.
 |
| Street View, Feb 2023 |
Unless you like the sound of the bell, skip to 1:00.
 |
| 8:16 video @ 1:51 "It has a 480-foot (150 m) span....Each 7,500-short-ton (6,800 t) leaf of the bridge floats on a 100-inch (2.5 m) steel barrel in hydraulic oil. It is claimed to be the only bridge of its type in the world and it has received several awards for its innovation, including the Outstanding Engineering Achievement Award of the American Society of Civil Engineers in 1992." |
I watch towboats handle barges, but not tugboats. Why is the barge dragging two chains?
 |
| @ 4:12 |
Repairs
The "Outstanding Engineering Achievement" seems to be a maintenance nightmare.
"As part of our proactive maintenance efforts, we carried out the initial phase of the Spokane St Swing Bridge Rehabilitation Program from 2020 to 2022. These efforts included injecting epoxy resin into existing cracks in the low bridge and adding carbon-fiber wrapping in several locations on both interior and exterior surfaces to strengthen the bridge." [sdotblog]
 |
| sdotblog_2023-09-25 |
It was closed three weeks starting Dec 23, 2022, to remove a cylinder for emergency repairs.
 |
| KOMOnews "During the three-week closure, the department said crews removed a damaged 15,000-pound cylinder, repaired underground power conduit and replaced valves and hoses on the eastern bridge span’s hydraulic power unit." [In another article, SDOT says the cylinder weights 20,000 pounds.] |
Here are SDOT's details about why it needed emergency repairs. The planned outage was for a week, but it ended up being three weeks.
The problem initially appeared to be associated with a computer issue that occurred while the bridge was powering back up after a power outage. Once the computer issue was resolved, engineers found previously identified minor issues with the hydraulic system that moves the bridge had intensified.SDOT completes regular inspections of the Low Bridge and had existing plans to repair these aging components in 2023. However, after the power outage, it was discovered that previously manageable small-scale issues had escalated into more severe problems. Until these components are fixed, the bridge cannot be reliably moved without risking more severe long-term damage.SDOT engineers are working as quickly as possible to analyze repair options. While there is not yet an estimate for how long bridge repair will take, SDOT expects the closure to last for at least two weeks.Based on the evaluation results, additional Low Bridge closures for repairs may be needed in 2023, along with closures associated with planned capital improvements to the bridge next year.
One week of outage was planned starting Oct 7, 2024, to reinstall the overhauled cylinder and remove the second cylinder for refurbishment.
 |
| mynorthwest, Photo from Seattle Department of Transportation The bridge opens about four times a day. They are confident that during the 3-week outage at the beginning of 2023 they learned how to remove and install a cylinder in 2-3 days per cylinder. |
They learned their repair lesson well because the outage was just 3 days instead of the planned 7 days.
 |
| SeattleBikeBlog, Image from SDOT "The department did not say how crews achieved this early reopening, but perhaps they have gotten very good at fixing this odd pivoting bridge because it breaks down so often....More closures will be needed in the somewhat near future to repair the other cylinders and the control system, though dates have not yet been announced." |
 |
| yahoo and fox13seattle |
The carbon-fiber wrap reinforcement is needed because cracks developed after just 3 decades of service. [kuow]
 |
| seattle This webpage details the maintenance work for the 9-day Apr 2024 closure. |
This bridge is a violation of the KISS (Keep it Simple, Stupid) principle. I wonder how many multi-day outages were suffered by the Government and Fort Madison bridges after just a few decades.
1924
When built, the 1917 bridge was considered temporary with a lifespan of 10 years. This replacement bridge was the first one built with concrete and steel. [whereiamnow, a history of the bridges to West Seattle]
 |
| pauldorpat "Rerouted westbound traffic clogs the 1930 West Seattle drawbridge during the afternoon rush hour of Monday, June 12, 1978, some 36 hours after the freighter Antonio Chavez rammed its companion 1924 span (right) and stuck it upward and beyond repair. (Greg Carter, West Seattle Herald, courtesy Robinson Newspapers)" The first bridge was built in 1924, and the second one was added in 1930. |
 |
| pauldorpat "The 1924 span of the Spokane Street Bridge soon after the June 11, 1978, ramming stuck it open. The recently opened Kingdome is seen in the background. (Greg Carter, West Seattle Herald)" West Seattle was organizing to succeed from Seattle so that they could get funds to build a replacement bridge. But a freight alliding with this bridge made succession unnecessary. [My notes on the High Bridge has more info about the allision.] It was replaced by the high bridge next to it. But in 1991, even the low bridge was replaced. Douglas Butler posted Spokane Street North Bascule Bridge was replaced crossing the Duwamish River in Seattle, WA source: Paul Dorpat. |
 |
| chron, License: Creative Commons Attribution (CC BY) |
 |
| Flickr, May 1, 1930, via BridgeHunter_1924, License: Creative Commons Attribution (CC BY) Seattle Municipal Archives Traffic on West Spokane Street Bridge, 1930 Item 4051, Engineering Department Photographic Negatives (Record Series 2613-07), Seattle Municipal Archives. |
1917
 |
| Douglas Butler via BridgeHunter_1917 |
No comments:
Post a Comment