Modeling and dynamic analysis of bridges designed with AASHTO and Florida I-beam girders

Abstract A comparative analysis of the dynamic behavior of two prestressed concrete girder bridges was implemented. The first bridge was designed with AASHTO (American Association of State Highway and Transportation Officials) type III girders while the second bridge was designed with the new (FIB) Florida I-Beam girders. Both bridges have the same length, width and girder depth. However, six AASHTO Type III girders were used in the first bridge versus only four FIB girders for the second bridge. The bridges response to dynamic loads was obtained with the aid of a sophisticated finite element model. Modal and time history analyses were performed for the bridges to identify the dynamic properties, behavior, and responses of the two bridges. The dynamic properties and the deflections of the bridges were obtained and compared for different girders and spans. Outputs from the finite element model indicated that although FIB bridge has less number of girders, the deflections of FIB bridge were less than their corresponding values from AASHTO bridge.