USING GNSS BASED SYSTEM FOR INVESTIGATION OF BRIDGES CONSTRUCTION DISPLACEMENTS

Nowadays there is an undeniable necessary for a continuous supply of information about the geometric and dynamic state of the structure. This is particularly important in the case of bridge which are exposed to additional factors such as improper use, overloading, river current with flowing material or extreme weather conditions. System which was developed in Military University of Technology allows to automate the monitoring process with the possibility of continues control of the bridge construction. The main element of the system are GNSS receivers which were used not only for determining high frequency position but also to integrate other sensors included in the system, e.g. inductive displacement sensors, inclinometer or robotic total station. All elements were integrated using control module with data acquisition server. This article presents the idea of the system, as well as tests which were carried out on permanent and temporary bridge crossings. At permanent crossings GNSS receivers where used to obtain displacements values in both of the horizontal and vertical directions. For improve the reliability of the obtained results inductive sensors and leveling were included into developed system and was tested on a single span temporary crossing located at the Military University of Technology. The measurement results showed that developed system can effectively monitor the real-time bridges with accuracies providing the opportunity to identify possible threats. Also the system has been designed as an open, which allows its extension to other sensors to increase its efficiency.