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| HAER PA,5-HOPEV,1--1 GENERAL VIEW OF BRIDGE, LOOKING EAST - Bedford County Bridge No. 4, Township Route 655 spanning Yellow Creek, Hopewell, Bedford County, PA |
"Significance: This steel-constructed Pratt through truss is a typical metal truss span of the late nineteenth century. It is, however, one of the region's few surviving Keystone Bridge Company spans built for wagon traffic." [HAER_data]
PRR Bedford Branch History Preservationist posted two photos with the comment:
Yellow Creek Bridge in Hopewell.Built in 1889 this is a Steel Pratt through-truss bridge. Built for wagon and car traffic to Hopewell Pa. Where it was a rail hub due to the H&BTM’s presence.This bridge was built by the King Bridge company. And is one of the last remaining examples of their work.The Pratt through-truss bridge was invented by Thomas and Caleb Pratt in 1844, the design features diagonal elements that handle tension and vertical elements that handle compression.This was the go to method of building bridges when we finally started to transition from wood frame to Wrought iron framed to steel framed.Most of these bridges are gone today because they were built to hold horse and carriages and couldn’t handle the weight of modern vehicles.So we are lucky to have some a fine and preserved example of this building method in our great county.
Art Suckewer: ....While they aren't designed for modern loads, they were designed to hold a load of cattle or a steam tractor - correctly restored, they can be rated for 15 - 20 tons. The real problem is 'the system' is no longer capable of maintaining, inspecting (I don't mean spotting 'stuff'; I mean understanding it's significance) or correctly restoring these old bridges. The true wrought iron is no longer made, few know how to properly hot rivet, fewer still know how to properly work the old metal or join it to modern equivalents. The engineers aren't trained in restoration and have restrictive rules imposed on them. On top of this, the system is set up for low bid, not quality. Thus, it's no surprise that the governmental entities that own these old truss bridges consider them money sucking white elephants! If done right, these old truss bridges are practical and affordable to restore and maintain. There are a bunch of people trying to change the way things are done but it's going to be a challenge.
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H&BTM = Huntingdon & Broad Top Mountain, which went from the Pennsy mainline in Huntingdon to the Pennsy Everett Branch.
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| PRR Bedford Branch History Preservationist posted via Dennis DeBruler |
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