The paper aims at providing a methodology for designing a system for monitoring launching girder operations on precast segmental construction projects. An optimal sensor placement strategy is developed to identify the current state of the launching girder with the minimum number of sensors. A class of structural models was created by varying the initial conditions and then analysed using a finite element analysis package to get responses at different locations. Entropy at these locations were calculated and the locations with the highest entropy is chosen as an optimal sensor location. Influence of precision of sensors in design of measurement system is also discussed in detail. Increase in precision results in increased information content and lesser number of sensors.