This paper aimed to assess structural performance of superstructures of typical RC bridge in Thailand. The static load test was performed to measure both horizontal and vertical displacement in Reinforced Concrete (RC) girder using Image Measurement System (IMS). The RC girder’s stiffness obtained from the IMS results is compared with that obtained from 3D Linear Finite Element Method. The stiffness from IMS is smaller than that from 3D FEM, indicating deterioration of RC girder. Besides, to predict the failure mode and capacity of RC girder, 2D Non-linear Finite Element Method. It was founded that the RC girder occurred shear and anchorage failure. In this paper, furthermore, the Load and Resistance Factor Rating (LRFR) is conducted to evaluate the performance of the bridge which has been designed by old LRFD specification. The results show that the moment rating factor and the shear rating factor for the designed load rating is equal to 1.20 and 1.01, respectively. From LRFR, the bridge still has sufficient capacity to carry both the AASHTO LRFD-design live load HL-93 and the AASHTO legal loads.