Random links of interest
Thursday, October 21, 2010
- Raymond Klein forwarded a link to a book from 1891 entitled
"Report of the Board of railroad commissioners of the state of New York on strains on railroad bridges of the state." Despite the dry title,
the book is quite fascinating, featuring simple drawings of the iron and steel railroad truss bridges in New York State. Glancing through
the book, I spotted examples of the elusive Whipple deck truss design.
- Illinois now has a website on the historic bridges in the state.
- Ohio has posted a revised version (from Sept. 27, 2010) of its
historic bridge inventory.
- This page on the Federal Highway Administration website describes various
kinds of bridge rails. Unfortunately, it appears that many of the safest designs are also among the ugliest designs.
- I haven't had a chance to download and convert any of the massive files, but this website
offers scanned images of 1890s-era maps from the Mississippi River Commission.
By the way, I was looking at the FHWA guardrail guide link listed above. I see a couple of Michigan's guardrails are used, including a retrofit of Michigan's beautiful R4 type railings. However the guide did not list Michigan's two-tube guardrail, which is a low profile low visual impact railing that is crash-tested and AASHTO approved, and is an excellent choice for historic bridge applications. The document also did not discuss a further use of these two-tube systems as an alternative way to retrofit the R4 railings in a more aesthetically pleasing way. These two-tube systems are good solutions that combine safety and aesthetics.
Also, the historic balustrade railings, generically called Texas railing http://3.bp.blogspot.com/_LBWeRsNcsFI/Rwvimc2EwcI/AAAAAAAABi8/eOGUGzoJRDY/S660/Texas+Rail_1744r.jpg but common in Indiana too are crash tested barriers.
Also, Chicago developed a narrower and more aesthetically pleasing alternative to the New Jersey Barrier. The Chicago Barrier has some aesthetic detailing and is not sloped to enable it to be used on roadways with limited width, such as the early limited access highway, Lakeshore Drive.
The Illinois list is unfortunately nothing new... its the same useless nonsense that state has promoted since day 1. The list does not display a statewide context for historic bridges, let alone any individual discussions for each bridge bridge. The lists tells us what bridges they think are NR eligible... but it doesn't tell us WHY they are, or if found ineligible, they don't tell us WHY NOT. This is inexcusable on the part of IDOT, and I have emailed them multiple times and been unable to get either a statewide context or an individual evaluation. For all I know they reached into a hat to randomly pull out bridges to be considered NR eligible.
Illinois HAARGIS remains the best source in Illinois to get actual information on historic bridges in Illinois, but this is only for NR LISTED bridges. http://gis.hpa.state.il.us/hargis/