Precision Geometric Levelling for the Control of Vertical Displacements in the Recovery and Reinforcement of Concrete Beam, a Case Study

Monitoring and control of large size civil works was an important and well known application area for topographical and geodetic methods, with a wide range of articles published. However, documented experiences applying precision geodetic methods in monitoring in a smaller scale (structural elements: beams, columns, slabs, etc.) are sparse. The main objective of this study is to evaluate and compare the use of precision geometric levelling technique with instrumentation with displacement transducers (structural instrumentation method) in vertical displacement control in a concrete beam with excessive deformation, being subjected to recovery processes and reinforcement. Although precision geometric levelling is not considered a modern technique in the structures monitoring, it is cost-effective feasible, accurate, and highly precise, with acceptable uncertainties and results, considering procedures normally followed in the processes of recovery and reinforcement related to this type of works. The results have shown that precision geometric levelling is an effective alternative, with remarkable advantages in assembling times and installation, as well as in monitoring post-recovery process of structures (medium and long term), and as the possibility of establishing a correlation between the behaviour of the monitored points. In addition, precision geometric levelling is a valid alternative to be implemented jointly with structural instrumentation techniques, especially where redundancy needs to be obtained in the observations.