Bridges, connecting communities and serving as regional lifelines, are vital components of the transport infrastructure. Current bridge evaluation techniques are mainly based on visual inspections, which are qualitative and fail to estimate the strength reserve capacities of bridges. Based on such methods, thousands of bridges in the UK are reported as structurally deficient in some form. These substandard bridges have a substantial adverse impact on our economy and environment. In this study, researchers from CSIC and LORc have instrumented two railway bridges owned by Network Rail with fibre optic sensing systems during their construction stage to deliver UK's first truly smart bridges. The project showcases the practical application of real-time structural monitoring integrated with digital twins to quantify the actual performance of the bridge and demonstrates the conservativeness involved in conventional bridge assessment techniques.