Investigation of the Code Proposed R-Factor in Design of Concrete Bridges with Neoprene

One of the problems in bridge design is the uncertainty in codes in defining the role of Neoprene comparing with the bridges with directly pier to deck connection (voided slab). In this study for investigation of the R factor, five models with a Neoprene connection between substructure and superstructure, and two models with direct connection between the pier and the voided slab, are developed. The average values of the R factor in the models with Neoprene were 4.28 in longitudinal direction and 5.90 in transverse direction. These values in the code are 3 and 5 respectively, showing that recommended R-Factors in code are conservative. Also in the bridges with directly pier to deck connection, the R factor in longitudinal direction was 2.92 that is close to the value in the code(equal to 3), but in transverse direction it was 2.41 that is half of the given value in the code (equal to 5).