DEAD LOAD DESIGN OF CURVED I GIRDER BRIDGES

In recent years we have witnessed an ever-increasing demand for curved girder bridge systems. This has created a need for reliable methods by which such systems may be designed and analyzed. Methods developed to date do not adequately account for the effects of both girder warping and the interaction of adjacent girders due to radial diaphragm action. For bridge systems subjected to dead load with no composite action, significant error in the calculation warping stress (flange bending) may result. The objective of this report was to develop a method of analysis for curved girder bridge systems and to develop a set of design aids to facilitate their design. Vaslov's Equations expressed in finite difference form are used to describe the structural response of the individual girders. The stiffness method is employed to express diaphragm action in terms of relative displacements of the adjacent girders. Inclusion of the expressions for diaphragm action into the finite difference form of Vaslov's Equations yields a system of linear algebraic equations which gives the behavior of curved bridge systems. This method of analysis is incorporated into a computer program, which is then used to conduct a parametric study. A thorough study of the interaction of the various bridge parameters has resulted in a set of design aids. These design aids can be used to determine the effects of curved bridge system parameters upon the maximum bending and warping stresses when the system is subjected only to dead load. Any assumptions pertaining to the magnitude of live load stresses may be subsequently verified by running the aforementioned computer program.