Minneapolis Pegram Truss Bridge

Located in Minneapolis, this historic Pegram through truss bridge crosses Pipe Creek, and is one of two bridges with this design in Kansas. The previous bridge here was likely a wooden truss or a light iron truss, constructed in 1879. In 1914, the bridge would be replaced with a secondhand 147-foot 6-inch, 8-panel, pin-connected Pegram through truss, set onto a stone and concrete abutment, with a timber pile pier. The truss span would be approached by timber pile trestle spans on the north end. The Pegram truss uses typical features seen on other UP Pegram trusses, including a lattice portal and laced members. This particular Pegram span was fabricated in 1893 by the Edge Moor Iron Works, and originally the smaller span of the Loup River Bridge in Columbus, Nebraska. The Loup River Bridge had been replaced in 1908 during a double tracking project, and the truss was stored at an unknown location for six years. A second, 203-foot span was also likely reused from that bridge, although it is unknown where it may have been used.

While George H. Pegram was working for Edge Moor Bridge Works, he patented his Pegram Truss design in 1885. Unlike a Parker through Truss, Pegram's design made use of a curved top chord with all members the same length. In addition, vertical compression members were all the same length as well on his designs. Not long after Pegram patented his design, he left Edge Moor to work for the Missouri Pacific Railroad. The first Pegram through truss span was built across the Verdigris River in 1889, for the Missouri Pacific. During his tenure with MP, many spans of this design were built, including a 13 span bridge at Ft. Smith, Arkansas; and 20 individual spans constructed in 1890 alone. By 1893, his reputation was well known, and he left MP to work as Chief Engineer for the Union Pacific Railroad. It seems he likely took advantage of this position to continue constructing his patented design. Pegram stayed at Union Pacific, until he left in 1898. The true number of Pegram trusses constructed is unknown.

While many of the Pegram trusses have been demolished, a number continue to exist throughout the western United States. Of the remaining spans, eleven are still intact in Idaho, two in California, two in Kansas and a single span in both Utah and Washington. Most of the spans were relocated and reused along after main line traffic became too heavy, as is the case with this bridge. The other remaining span in Kansas, the Republican River Pegram Truss near Concordia, was reused from an unknown bridge, although it is possible the other Columbus span was reused there.

Since the 1914, the bridge has seen few changes. The south abutment of the bridge consists of stonework from 1879, as well as various concrete repairs. The timber components of the bridge have likely been updated since it was initially constructed. The floor appears to be original to the 1893 fabrication of the bridge. Overall, the bridge appears to be in fair condition, with no significant deterioration noted. The author has ranked this bridge as being nationally significant, due to the Pegram design.