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Washington Avenue Bridge,
Bridge No. 4534
• Washington Avenue over Mad River
• Wrought-iron lenticular pony truss
• Length: 63'
• Built in 1878
• Corrugated Metal Company, fabricator
This bridge was constructed in 1878, the year that Corrugated Metal Company of East Berlin, Connecticut, began making bridges. It is one of only two known surviving bridges from this important fabricator's first year.
Bridge fabrication saved Corrugated Metal Company from bankruptcy. The company's business in metal roofing, roof trusses, and fire-proof shutters was failing in 1877, when engineer William O. Douglas joined the firm. Douglas, a graduate of the U. S. Military Academy, had devised an unusual truss with curved top and bottom chords. The lenticular or parabolic truss, which Douglas patented in 1878, quickly became a success. The Corrugated Metal Company, known after 1883 as Berlin Iron Bridge Company, claimed to have built more than ninety percent of the highway bridges in New England in the period 1878-1888. Waterbury alone bought more than a dozen Berlin bridges.
Although a modern beam structure now bears the weight of traffic, the distinctive profile of the bridge's lenticular truss is clearly visible. Also, the bridge retains its original lattice railing. Its orb finials and cast-iron rosettes were distinctive to Corrugated Metal and Berlin Iron Bridge Company and appeared on their bridges through the 1890s.