Service, fatigue, and ultimate load evaluation of a continuous prestressed flat-slab bridge system

RA Cook, FE Fagundo, AD Rozen, H Mayer - Transportation Research …, 1993 - trid.trb.org
RA Cook, FE Fagundo, AD Rozen, H Mayer
Transportation Research Record, 1993trid.trb.org
A new type of short-span bridge system for traversing wetlands and shallow waters (ie, a
trestle-type bridge) has been developed and implemented over the Albemarle Sound south
of Edenton, North Carolina. The new system incorporates precast flat-slab sections that are
posttensioned for continuity. The new system has the potential to replace traditional trestle-
type bridges constructed using simple-span prestressed beams with a cast-in-place deck. A
continuous two-span, half-scale model of this precast, posttensioned, flat-slab bridge system …
A new type of short-span bridge system for traversing wetlands and shallow waters (ie, a trestle-type bridge) has been developed and implemented over the Albemarle Sound south of Edenton, North Carolina. The new system incorporates precast flat-slab sections that are posttensioned for continuity. The new system has the potential to replace traditional trestle-type bridges constructed using simple-span prestressed beams with a cast-in-place deck. A continuous two-span, half-scale model of this precast, posttensioned, flat-slab bridge system was built and tested under various load conditions. The bridge was evaluated analytically and experimentally for the transfer load case (dead load plus prestress), the maximum negative moment service load case, the maximum positive moment service load case, fatigue load, cracking load, and ultimate load. The model bridge performed as predicted for all load cases. Comparisons between analytical and physical models showed good correlation for all types of tests. At service load levels the bridge exhibited an elastic response with no evidence of cracking. The results of the fatigue load tests showed no degradation of stiffness. The ultimate load and deflections of the new bridge system were readily predicted by standard behavioral models for prestressed concrete. With the cost savings, short erection time, and multispan continuity of this system, it should be considered a viable alternative to the standard girder systems available for trestle-type bridges.
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