Lacon Bridge

Lacon Bridge
Coordinates	41°01′33″N 89°25′00″W
Carries	Two lanes of Illinois Route 17
Crosses	Illinois River
Locale	Lacon, Illinois
Official name	Lacon Bridge
Maintained by	Illinois Department of Transportation
ID number	000062000314852
Characteristics
Design	Steel truss through deck bridge
Total length	1,573 feet, 378 feet at it's longest span
Width	2 traffic lanes, 26 feet (12 meters)
Height	60 feet above water, 500 feet above sea level
History
Opened	1939

The Lacon Bridge is a crossing of the Illinois River in the community of Lacon, Illinois. Built in 1939, it is one of the oldest crossings of the Illinois River.

Description/History

A very large steel through truss bridge carries Illinois State Highway 17 across the Illinois River south of the LaSallePeru area and north of the Peoria area. This little farming community sees relatively little traffic. This style truss bridge is called a continuous truss as opposed to a simple truss frame. A simple truss has two piers, one at each end point. A continuous truss has 3 or more piers. In the case of the Lacon Bridge, it has 4 piers, one on each end, and two mid-channel. The continuous truss bridge is one rigid structure that spans more than 2 piers. In contrast, we often see simple trusses mounted back to back across 4 to 6 piers, as in the Henry Bridge just up stream. The continuous truss can be built with longer main channel spans than simple truss bridges, so they are used in cases where you want a wide navigation channel. There are many continuous truss bridges over our major rivers, but they have the disadvantage that they are costly to maintain. As a result, new bridges are being built using the cable stayed method (like the Clark Bridge in Alton) or the post-tension concrete segment method (like the new I-35W Bridge in Minneapolis).