Arch bridges are widely used for historical bridges worldwide for decades. The reinforced concrete open spandrel arch rib bridge is one of the typical types among them. In this study, a refined finite element analysis model is proposed on a historical reinforced concrete arch bridge to investigate the effects of arch rib boundary restraints and temperature changes on the performances of the selected arch bridge. Comparisons are conducted among the results of the finite element analysis models where fixed, hinged, and elastic rotational spring restraints are applied to the arch rib ends, respectively. Additionally, the effect of temperature change is evaluated for the internal forces of the arch rib. It is observed that for the selected arch bridge with arch ribs being framed into pier columns which are supported by spread footings, hinge restraints are more appropriate for characterizing the bridge behavior. Additionally, it is observed that the thermal load due to a typically daily temperature change in Virginia has a minor effect on the performances of the investigated arch bridge.