This is a two-span pin connected Pratt through truss bridge built in 1893. Each of the two 129 foot spans has eight panels. The composition of the truss is as follows (measurements accurate to within 1/2 inch): end post and top chord: 16 x 10 inches, back-to-back channels with v-lacing and cover plate; vertical members, back-to-back channels with v-lacing on each side, varying dimensions including 9.5 x 7 inches and 8.5 x 6 inches; hip vertical members: loop-forged four-prong "claw" bars; diagonal members: loop-forged eyebars, varying dimensions including widths of 3 inches and 1.5 inches; bottom chord: up-set eyebars; portal bracing: traditional lattice mesh with paired angle borders, with curved knee sections; struts: rolled American Standard Beam i-beams with a riveted plate fastened on both the top and bottom; floorbeams: rolled American Standard Beam i-beams; deck stringers: rolled American Standard Beam i-beams; vehicular deck: hot mix asphalt on corrugated steel base; sidewalk deck: traditional wooden deck; pedestrian railing: ornate lattice design, 33 inches in height; vehicular railing: traditional lattice design, 24 inches in height; abutments and pier: coursed ashlar.
Everything on this bridge except for the asphalt vehicular roadway deck is historically accurate, from the intact guardrails to the plaques on the bridge. The bridge has remarkable historic integrity including unaltered design and large percent of original bridge material. There are some welded repairs to the bridge, but all were minor and did not detract from the original design and appearance of the bridge. The guardrails on this bridge are beautiful, especially the unique pedestrian railing on the single cantilevered sidewalk on the bridge, which is quite ornate, including an unusual lattice design that also features decorative cast flower motifs. There are also cast iron details at the outriggers for the pedestrian railings. These pedestrian railings terminate in ornate cast iron end posts. One section of vehicular railing was repaired with new angles, but this was done in kind and was not easily noticeable. There is lattice vehicular railing on each truss line. The placement of lattice railing on the truss line that is next to the sidewalk is unusual, traditionally railing was only placed at the extreme edges of the bridge, whether that be the edge of the sidewalk, or at the truss line.
Despite its common truss configuration, the remarkable integrity of this bridge as well as its multi-span configuration make it stand out among the rich collection of historic bridges in northwestern Pennsylvania. The bridge has a high level of historic significance as an outstanding representative example of a once-common bridge type that is today rare.
Despite what appears to be a fresh coat of paint at first glance, this bridge was closed to traffic for many years before PennDOT moved to demolish the bridge. The paint on the bridge overall was in good condition, given how long the bridge sat abandoned. The only exception was in the most common trouble spot, the bottom chord connections and other isolated areas, particularly at and below the deck level. These areas showed signs of significant section loss and pack rust. The reality is that this bridge could have likely remained open to traffic for many years longer, or sat in place for pedestrian use only for many years, had minor spot painting and cleaning taken place over the years of this bridge's service life, particularly at the bottom chord connections and the bearings. The relatively good condition of the paint elsewhere is what suggests that only spot painting in the trouble spots was likely needed during the time the bridge was open to traffic. However, because these low-cost repairs and maintenance activities were not undertaken, after many years of sitting abandoned, one span of the bridge became unstable and at risk for collapse, prompting PennDOT to order emergency demolition of one of the finest historic bridges in northwestern Pennsylvania, a region noted for one of the best collections of historic bridges in the country. The fate of this bridge highlights how truly broken our nation's surface transportation policy is. Because simple, low-cost maintenance and repair is not funded and mandated, not only are priceless historic treasures being destroyed by neglect, but tax payer dollars are being wasted and the nation's infrastructure quality also suffers. This is to say nothing of the fact that this bridge was intended to honor the veterans of Venango. Any modern bridge that might replace this bridge, or any modern bridge elsewhere that might be designated a similar memorial bridge will be a typical ugly slab of concrete and will not do much to honor the sacrifice of any veteran. This historic bridge, rich in beauty and history, was the perfect structure to be a memorial to the veterans of Venango. Because this bridge was not preserved however, this memorial will be destroyed, which does not seem very respectful to Venango's veterans.
As mentioned, one span of the bridge suddenly became unstable and at risk for collapse. Specifically, the endpost at the northern corner had buckled severely, the end post assuming a horseshoe-like shape near the base. HistoricBridges.org observed significant section loss on the channels of the built-up endpost at the point where the buckling occurred. The section loss likely weakened the end post, greatly reducing its bending resistance. Such section loss could have been repaired all too easily years ago by simply cleaning the area and then welding a small plate of steel to the channel. But was this the only problem that led to the buckled endpost? It appears not. Luke Gordon, HistoricBridges.org's Engineering/Construction Consultant examined the bridge and suggested that the problem may have been triggered because an extremely simple act of maintenance was not undertaken years ago... simply sweeping and cleaning dirt from the bearings of the bridge at the northwest end. The bearings at the northwest end of the bridge were found to have been severely deteriorated and literally buried in dirt. Being buried in dirt (which traps moisture) likely led to rapid deterioration of the bearing. Worse, as if the deterioration along was not bad enough, the dirt packed in around the bearing also further prevented the bearing from moving. Bridges need to be able to move due to normal changes in temperature and other weather-related factors, and when in service, also from changing live loads on the bridge. Further, bearings can help compensate for any minor shifting in the abutments or piers to a limited extent. Without this ability to flex, even a tiny amount of temperature change or shifting of the abutment may have been enough to cause the weakened endpost to buckle. The result of the buckled end post was all too obvious. The portal bracing at the northwest end of the bridge twisted severely, the hip vertical bent severely as well, and a broken eyebar was found under the bridge.
Despite this disaster, HistoricBridges.org wants to make it very clear that even in this condition, this bridge could and should have still been preserved, rather than demolished as PennDOT has chosen to do. At the very least, the southeastern span could have been preserved, likely by relocating it to a new location for non-motorized use. The southeastern span was not affected by the end post buckling. If just the southeastern span was preserved, parts from the northwestern span could have aided in the restoration of the southeastern span. However, if the will was there, restoring the northwestern span would have been possible as well. The span could be lifted off and the buckled and broken parts, (only about three sections of member and chord) could be replicated, and the bent portions could be either replicated or straightened using a routine heat-straightening method.
Information and Findings From Pennsylvania's Historic Bridge Inventory
Discussion of Bridge
The 1893, pin connected, two span, 261'-long, Pratt thru truss bridge is supported on an ashlar pier and abutments. It was fabricated by the Wrought Iron Bridge Company, and the hip floor beam hangers have their distinctive four-pronged detail. The cantilevered sidewalk is finished with a handsome lattice railing. Crawford County is rich in pin connected, metal truss bridges with 35 ranging in date from 1870 through the early 20th century remaining. This bridge stands out as a long, complete, multiple span example of its type and design. Adding to its significance is its documentation to a prominent fabricator. The bridge is historically and technologically significant.
Discussion of Surrounding Area
The bridge carries a 1 lane street and sidewalk over a stream on the east edge of Venango borough. It is not contiguous to the developed area, which consists primarily of undistinguished, early 20th century vernacular houses, most with modern siding and altered windows. Southeast of the bridge is a wooded, sparsely developed area. The setting does not have historic district potential.
Bridge Considered Historic By Survey: Yes
This historic bridge has been demolished. This map is shown for reference purposes only.
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