A Method to Calculate Rotational Deformations of Curved Plate Girders during Lifting

The design of curved I-girders is complicated due to the many performance stages that must be evaluated, including erection, construction, and in-service. Evaluation of girder stability during early stages of construction is particularly complicated due to the limited presence of bracing. In addition to stability issues during girder lifting, guidelines for the necessity of shore towers during erection are also not available. The Texas Department of Transportation has funded a research project to investigate girder stability during early stages of construction. Results from this research project will be used to develop guidelines for the evaluation of girder stability during early construction stages as well as proportion the girder cross sections for safe and economical construction. The research includes: (1) field monitoring, (2) a parametric study using finite element analysis, and (3) the development of a user-friendly finite element analytical software that will serve as a tool for designers. Field studies have been successfully conducted on a bridge that is a part of the SH 130 Turnpike Project near Austin, TX. Data was collected for the validation of a 3-D finite element model. Recommendations were made to provide guidance for safely lifting horizontally curved steel I-girders. This paper will provide a summary of results from the field studies that have been used to validate finite element models of the curved girders during girder lifting. A method for calculating the rotational deformation of curved I-girders during lifting and results from the parametric investigations that are currently underway will also be discussed.