DESIGN OF CONTINUOUS HIGHWAY BRIDGES WITH PRECAST, PRESTRESSED CONCRETE GIRDERS

Continuous highway bridges with precast, prestressed girders have been built by a number of states. Examples of bridges of this type built by the states of Tennessee and California are presented in Figs. 1 and 2, respectively. The Big Sandy River Bridges in Tennessee were built in 1963-64. Performance has been excellent. The 639-ft. and 703ft. continuous lengths of deck slab on these bridges are believed to be the longest built to date supported on precast, prestressed girders. The Los Penasquitos Bridge in California was a 1966 PCI award winner. A primary reason for using continuity with precast, prestressed girders is the elimination of the maintenance costs associated with bridge deck joints and deck drainage onto the substructure. Continuity also improves the appearance and the riding qualities of this type of bridge. Due to the structural economy of continuous designs and the elimination of the deck joint details, some initial economic advantage may also be obtained. The construction sequence for the type of bridge under consideration is shown in Fig. 3. Continuity is