Thermally-Induced Deformations and Stresses in a Steel Trapezoidal Twin-Box Girder Bridge

Curved-span steel bridges are becoming increasingly popular. Box girders are optimal for use on such spans, as the large torsional stiffness of a closed section is often more economical than the use of several “open” sections.

Pot bearings are often used with box girders in such bridges. These bearings can accommodate relatively large rotations, and, when used with sliding surfaces, can accommodate significant translations, as well.

The bridge under investigation uses both box girders and pot bearings. It is desired to know what deformations--translations and rotations--may be reasonably expected to occur at the bearings during the year due to temperature changes within the structure. This thesis describes the analytical and experimental investigation of the bridge under study to determine what deformations develop at the bearings. Measured deformations are compared to theoretical values, and other findings are discussed.