EFFECTS OF RESTRAINED THERMAL MOVEMENT IN A CONTINUOUS, PRESTRESSED CONCRETE BRIDGE WITHOUT INTERIOR EXPANSION JOINTS

In their standard practice for the design of bridges for thermal effects, the AASHTO Specifications call for expansion devices to be taken into consideration in design. In recent years, the Tennessee Department of Transportation has taken the lead in the omission or reduction in the number of expansion joints in designing bridges for temperature effects. This reduction in expansion devices decreases the maintenance and construction costs as well as improves the riding quality. The bridge which is the subject of this investigation is 2700 feet long and has no expansion joints except at the abutments. Strains and movements will be induced due to the continuity and restraint of the structure.; An understanding of bridge behavior due to thermal effects is needed for the designer. Most of the existing codes have no direct provisions which guide the designer on how to calculate the thermally induced stresses and movements.; The purposes of this dissertation are manifold. Its primary purpose was to develop and present a theoretical method for calculating thermal stresses and movements in continuous bridge structures. Another objective of this research was to collect and analyze experimental data obtained from strain gages and thermocouples that have been placed in the piers and deck. A third purpose was to compare the field data obtained with those predicted from theory.; The nonlinear distribution of temperature throughout the depth of superstructure, which was obtained from measurements, was divided into two parts: a linear temperature distribution which causes deformation and another part which is nonlinear and results in self-equilibrating stresses which do not cause any deformation of the structure.; From the comparisons made between the data obtained from field measurement and the method presented in this research, a good agreement was achieved for stresses and movements.; It was also shown that the thermal stresses were typically greater than dead load stresses, and that the movements of the deck were proportional to mid-deck temperature.