An ABC approach helped UDOT keep traffic moving during construction of the Telegraph Street Bridge.
The monolithic poured bridge was still in good shape for a more than 70 year old structure. But the roadway on either side was wider, witch made the bridge a traffic choke-point. Building a twin bridge to add additional capacity would have been expensive – both to build and maintain through the life of the new bridge.
“Bridges are more expensive to maintain than roadway,” says Joshua Sletten, UDOT Structures Design Engineer. Per foot maintenance costs of roadway maintenance are a fraction of the costs of maintaining a bridge – especially a long structure like the old bridge. Hydrological studies showed that a smaller structure would also be adequate to accommodate a stream under the bridge. A UDOT in-house design called for a new smaller structure to be built under the bridge deck.
The new bridge, a giant arched culvert, was built using pre-formed concrete components that were assembled on site as traffic was maintained on the old bridge. After construction, fill was placed over the new structure and the road was realigned over the top. Crews then demolished the old bridge, and the built a new wider road with two lanes in each direction and a center median.
Covering the new structure also adds a maintenance advantage; the fill provides a protective buffer between traffic and the structure.
For more, read an earlier post about how UDOT partnered with stakeholders during construction.