Final report on the Long bridge expansion. Several items stood out.
1. Present clearance is 110' wide by 20' above mean high water. Desired to maybe double or triple those figures.
2. Loading went to Coopers E-40 to E - 65 to present E-80. However there are doubts as to the E-80 rating and study says that number and a detailed survey is needed of the underwater supports. As well the grade of steel used is unknown and needs investigation.
3. At present due to the concerns of #2 trains are limited to speeds of 20 - 30 MAS.
4. Recommended that no acceleration or braking occurr on bridge until concerns are addressed as suspicion that E-80 cannot be maintained under these conditions.
5. Bridge is an opendeck.
6. Possible that bridge only has 20 years life left.
7. Overhead clearance was listed as 20 feet. If that is true then modifications will be needed to reap benefits of the rebuilt Virginia ave tunnel.. This also requires that out of service CAT hangers re removed as well.
8. Open deck construction speeding corrosion.
As usual there is more than first meets the eye.
http://ddot.dc.gov/sites/default/files/dc/sites/ddot/publication/attachments/LongBridge_ExectuveSummary_Chapters1thru3_0.pdf
For those who may be wondering (and don't open the report) this would be the former PRR bridge in Washington DC over the Potomic River. Interesting they give options of two tracks and four tracks but not three.
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When I opened the pdf, it ended at 84 pages in my viewer.Was there a hard determination made in the report as to what would be the single best choice (say, recomend 4 track + pedestrian lane, standard girder with concrete arch clading construction, which seems best to me)?
chutton01 When I opened the pdf, it ended at 84 pages in my viewer.Was there a hard determination made in the report as to what would be the single best choice (say, recomend 4 track + pedestrian lane, standard girder with concrete arch clading construction, which seems best to me)?
If there are the 'alledged' 20 years of life left in the bridge, the decision on the replacement won't be finalized for 25 years. DC politics and all!
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