PUBLISHED In Structure Health Monitoring (SHM), it is commonplace to model a structure to predict how it will behave. However, creating realistic models can be a changing endeavour due to the information required about the structure. Support conditions are one of the most important structural properties affecting a model. Even if construction drawings are available, these boundary conditions can be hard to identify as the supporting properties can change over time with the deterioration of the bearing structures. This study presents a short-term monitoring regime to monitor the bearing movement of an in-service bridge to determine the boundary conditions of the bridge. The SHM system consists of optical displacement and temperature sensors with remote logging capabilities. The data shows how the fixed and movable bearings respond to changing temperatures and the differences between the north and south side of the bridge. The work undertaken in this study gives a method for a short-term monitoring scheme that can reduce the uncertainty in the structural modelling process.