View West, Bridge Deck
Photo taken by Historic American Engineering Record
View photos at Library of Congress
BH Photo #210309
What are the numbers coming back from the new concrete bridges. Do we have any statistics on life span or maintenance for those.
Thanks Nathan, I can always count on you for the dirt. I am also defining, in few words, "Restoration In-Kind". I checked out Bridgeport and Vern and a few other sites for those words and am coming up with the bullets for our proposal. I shall post when more complete.
Read the HAER data pages for the bridge. http://lcweb2.loc.gov/pnp/habshaer/pa/pa1700/pa1791/data/pa1... You will see in their detailed discussion that the bridge deteriorated rapidly, giving many problems over time. The 1990 rehab was so extensive and required so much removal of original bridge material it is described in one place as a superstructure replacement. The extent of the "rehab" apparently also was an adverse effect under Section 106, triggering the production of the aforementioned HAER documentation.
In Michigan, we also have an early, histoic pre-stressed concrete bridge. It also shows deterioration: http://www.historicbridges.org/michigan/ganson/
PennDOT claims pre-stressed concrete bridges last 100 years. I have seen nothing to prove this, and instead many pre-stessed concrete bridges only 50 years old are being replaced. Metal truss bridges are a far more durable and reliable bridge type, as long as the paint system is maintained. To see the potential service life of a historic metal bridge, we must look to the older and more properly maintained bridges of England. Example: http://www.historicbridges.org/inventoryearth/b_a_displaybri...
Rehabilitation in 1990. Do you know how it stood up to time Nathan (or any of you), or what the rehab was? Just checking my facts as to how lone a concrete bridge will utilimately last, versus a maintenance plan on a truss bridge.
It should be noted that this is the first MAJOR pre-stressed concrete bridge. I found a 1950 advertisement in the Technograph that suggests that the famous Roebling Sons and Company may take credit for the first... or one of the first... pre-stressed concrete bridges, said bridge having been constructed in Madison County, Tennessee.
Roebling Sons always specialized in wire, and the tensioned tendons within pres-stressed concrete are also wire-like so it makes sense that Roebling Sons was involved with pre-stressed concrete.
NBI #674015002000000, but where does this number go?