Prestressed concrete beams--Fatigue

This dissertation is a study of 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee bridge system, representing a target bridge of 70 ft. span. Theoretical analysis was carried out for comparison using different modelling techniques, such as isotropic and orthotropic material behavior, and the load distribution theory. Behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack patterns and growth with increasing number of cycles of fatigue loading. The precast model beams were assembled and tested at the Department of Ocean Engineering, Florida Atlantic University. AASHTO HS20-44 truck loading was simulated by applying constant amplitude fatigue loading at typical locations. The study established the feasibility and structural adequacy of the precast prestressed concrete double-tee concept for short and medium span interstate highway bridges for use in Florida and elsewhere.

The feasibility of the use of double-tee beams in a bridge system is examined by conducting tests on a 1:3.5 scale model of a two-span transversely and longitudinally post-tensioned continuous double-tee beam system. Constant amplitude fatigue loading was applied on the model at typical locations simulating HS 20-44 AASHTO truck loading. The behavior of the bridge system was evaluated in terms of deflections, wheel load distributions, crack growth and patterns with increasing number of cycles of fatigue loading. A finite element analysis of the bridge system was done using plate and beam elements and results compared with experimental values.