Scale Model for the Evaluation of a Continuous Prestressed Flat-Slab Bridge System


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Title: Scale Model for the Evaluation of a Continuous Prestressed Flat-Slab Bridge System

Author(s): R. A. Cook and F. E. Fagundo

Publication: Special Publication

Volume: 143


Appears on pages(s): 81-96

Keywords: bridges (structures); concretes; cracking (fracturing); deflection; flat concrete slabs; load tests (structural); models; moment-curvature relationship; post-tensioning; prestressed concrete; segmental construction; spans; tests; Design

Date: 5/1/1994

A new type of short-span bridge system has been developed and implemented over the Albermarle Sound south of Edenton, North Carolina. The new system incorporates precast flat-slab sections that are post-tensioned 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 the 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, cracking load, and ultimate load. The model bridge performed as expected for all cases. Comparisons between analytical and physical models showed good correlation for all types of tests. At service load levels, the bridge exhibited a linear elastic response with no evidence of cracking. The ultimate load and deflections of the new bridge system were readily predicted by standard behavioral models for prestressed concrete.