Abstract—Crack expansion behavior due to temperature changes has a significant influence on the soundness of reinforced concrete bridges. In this study, the expansion of cracks by Alkali-Silica Reaction (ASR) was investigated using long-term remote monitoring on a four-span pre-stressed concrete (PC) rigid-frame bridge. To evaluate the workability of a deteriorated bridge, instead of only focusing on the deformation of cracks under external loads, the consideration of environmental temperature factor is also needed. By analyzing the relationship between temperature changes and displacement behaviors over time, the ASR-induced crack expansion trend had been obtained. After that, the prediction of ultimate status of this bridge under extreme and normal working conditions was discussed. The monitoring results showed that the ASR-induced cracks are getting wider over time. Furthermore, the results of the study also supported that since the objective bridge is designed with Gelber hinges, there are spaces for deformation between two spans, which make displacement easier to occur throughout the year, from spring to summer in particular. Finally, this study provides information about the relationship between the behavior of a typical ASR-deteriorated PC bridge and environmental thermal effects at a specific time of the year.