This paper presents a methodology to use structural responses to monitor the progress of construction processes. The methodology was implemented on a launching girder used for viaduct construction of a metro rail project. A strain-based wireless sensor network was used for data acquisition. Structural responses from the launching girder were used to identify the state of construction. A conventional System Identification Methodology was tested for this application but was not accurate in inferring the stage of construction. Therefore a modified system identification strategy using derived features and heuristics was used to infer the state of construction. The modified methodology was found to be significantly more accurate than the conventional methodology and is well suited for applications in unstructured construction environments. Results from the case study confirm that the use of structural responses is feasible for measuring the progress of construction activities. © 2016 Elsevier B.V.