Master of Science
Tubular flange girders (TFG) are an innovative I-shaped steel bridge girder proposed for horizontally curved bridge systems. The I-shaped TFG has a steel tube flanges rather than a conventional flat plate flange for one or both flanges. The closed tube section significantly increases the torsional stiffness of the section and the open I-shaped section provides flexural stiffness. The increased torsional stiffness of the TFG significantly reduces the warping stresses, total normal stresses, vertical displacements, and cross section rotations for an individual curved TFG relative to a conventional curved I-girder.In this study, a type of tubular flange girder, called TFG1, with a rectangular hollow steel tube as the top flange and a flat plat as the bottom flange was studied. A two-thirds scale TFG1 bridge girder test specimen with two girders connected with diaphragms was studied. The specimen was designed by Ma (2014) and Putnam (2011) based on AASHTO LRFD Bridge Design Specifications (2005) and TFG design recommendations by Dong (2008). The test specimen was constructed, erected, and assembled in 2010. Ma (2014) investigated the expected behavior of the test specimen based on the FE models, and Hampe (2012) designed the loading fixtures for the tests of the specimen. This thesis reviews the test setup and designed loading fixtures, and presents plans for conducting of the tests, as well as the final test results.The design of the two-thirds scaled two-TFG1 bridge test specimen and the corresponding full-size twp-TFG1 bridge are reviewed. The full-size bridge has a 90 ft span, and a curvature ratio of 0.45. The scaled test specimen has same curvature ratio, but all dimensions are scaled by two-thirds. The test setup location and layout, and the expected behavior of the test specimen are summarized. Test loading fixtures designed by Hampe (2012) to simulate a uniformly distributed load condition are reviewed. Then, a study on the effect of alternate boundary conditions is presented and the design of the final set of bearing assemblies is described.The instrumentation plan developed for measuring the test specimen response is described. Geometric calculations required to obtain displacement components from the measured data are discussed. The loading plan, including the load control plan and jack re-stroking plan, is discussed. The instrumentation and loading plan were based on the expected behavior of the test specimen and loading fixtures, with focus on the conditions of the inelastic test which loads the test specimen up to and beyond its maximum load capacity.The data from tests on the test specimen were collected and analyzed and the processed test results are presented. The test specimen material properties from tensile tests of the test specimen materials are presented. An investigation of geometric imperfections of the tube flange at a tube splice location, near the region where the test specimen failed, is also presented.The results of the study show that the test loading fixtures, instrumentation, loading equipment, and load control plan performed well and produced reliable test data. The results of the tests have been used to validate FE models and design criteria for TFG1 bridge girders (Ma,2014).
Mahvashmohammadi, Kourosh, "Tests of Horizontally Curved Tubular Flange Girder System" (2014). Theses and Dissertations. 1552.