In this research paper, a 3-D finite element model was used for the analysis of curved concrete slab on steel girder bridges. A parametric study was carried out to calculate the load distribution factors for horizontally curved steel I-girder bridges based on (AASHTO LRFD) live loads .The bridges are analyzed by three dimensional finite elements using SAP 2000 software (Structural Analysis Program) with shell elements. The parameters considered in this study were: span-to-radius of curvature ratio, span length and the analysis of bridge will be performed for the case of full live load and partial live loads. The full data are given together with AASHTO LRFD calculations up to L/R equal to (0.6).