Post-tension Bridge Construction

Kansas One of the First States to Use Technique on Interstate Bridges

Post-tensioning is improving the quality and life of bridges on the Kansas Interstate system. When water and road salts enter cracks in the pavement, they deteriorate the slab and corrode the deck reinforcing steel. Post-tensioning uses cables in tubes embedded along the width and length of the concrete. When the cables are pulled tight, they squeeze the concrete, making it stronger and minimizing cracks, which greatly extends the life of the bridge. It also allows a designer to extend the maximum span length about 45 percent - from 64 feet to 92 feet.

Kansas is one of the first states using post tensioning on Interstate slab bridges. KDOT started using the technique on haunched slabs on the Interstate system in 2002. There are three post-tensioned slabs on I-70; one in Shawnee County and two in Wabaunsee County. Extending the span on this type of bridge allows for more uses in locations across the state rather than constructing a girder bridge, which is less durable.

The reinforced concrete version of this bridge is already one of the most dependable structures in Kansas. Extending the maximum span length using post-tensioning is an economical and practical way to improve bridges in Kansas.