Box Girder Bridge - Construction - Advantages and Disadvantages

Advantages and Disadvantages

Compared to I-beam girders, box girders have a number of key advantages and disadvantages. Box girders offer better resistance to torsion, which is particularly of benefit if the bridge deck is curved in plan. Additionally, larger girders can be constructed, because the presence of two webs allows wider and hence stronger flanges to be used. This in turn allows longer spans. On the other hand, box girders are more expensive to fabricate, and they are more difficult to maintain, because of the need for access to a confined space inside the box.

Corrosion of the steel cables that provide the post-tensioning for box girder bridges has become a major concern. On December 13, 2009, the Indiana Department of Transportation (INDOT) closed the Cline Avenue (SR-912) bridge over the Indiana Harbor and Ship Canal after a routine inspection revealed significant corrosion of the steel tensioning cables and rebar within the box girders due to water seeping through cracks in the bridge deck. After determining the level of corrosion compromised the bridge's structural integrity beyond repair, INDOT decided to permanently close and eventually demolish the span.