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Pine Creek Park Bridge
• Park Road over Pine Creek
• Wrought-iron pony truss
• Length: 54'
• Built 1870-1872
• J.H. Linville, engineer
• Keystone Bridge Company, fabricator
Like Riverside Avenue, this rare Keystone-column bridge was originally a railroad structure. Built as an approach span to an 1872 drawbridge in Middletown, it was re-used in 1890 to carry Mill Hill Road in Fairfield over the tracks of the New Haven Railroad. In 1979, the bridge was relocated to a town-owned conservation area.
Its compression members are octagonal columns patented by the Keystone Bridge Company of Pittsburgh. The Keystone column consists of four rolled segments riveted together through cylindrical spacers. Because the spacers are graduated in length, the columns are thicker in the middle than at the ends. According to the company, this gap allowed the interior of the column to be inspected; in some of their bridges, the gap was used to allow diagonal tie rods to pass through the uprights without the need for special fixtures. Principally, however, the gap represented an easy way to make a tapered wrought-iron column that was similar to the cast-iron columns the company had used in bridges like Riverside Avenue.
Although it stopped using its patented columns, the Keystone Bridge Company continued as one of the country's largest bridge fabricators until 1900, when it was absorbed by the American Bridge Company.