Use of Stay-in-Place Forms for Concrete Bridge Decks in Tennessee

Bridge decks, concrete or otherwise, represent one of the most heavily deteriorated components of typical highway bridges. Bridge construction continues to proceed at high volume, and in the past, bridge repair, rehabilitation, and replacement increased as well. Enormous amounts of funding are required to support initial construction and repairs as needed. This national trend is also evident within the Tennessee bridge inventory, which currently numbers approximately 20,000, with a majority of the structures utilizing concrete cast-in-place decks. Because of the increasing volume of work and limited funding, efficient methods of constructing and repairing concrete bridge decks have been of interest during the past decades. Durable, high-quality bridge decks have been constructed in Tennessee with three primary forming systems: temporary forms and falsework and stay-in-place form systems consisting of precast concrete panels and permanent steel forms. Each of these form systems is discussed, with a description of typical applications and estimation of the frequency of use. Currently, cast-in-place decks in Tennessee represent approximately 60% of the inventory and are predominantly (90%) cast by using permanent steel forms. The effects of stay-in-place forms on finished cast-in-place decks were investigated as well as form durability and inspection and repair considerations. This information was obtained through review of Tennessee Department of Transportation specifications and standard drawings and interviews of department personnel.