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This paper will give detailed overview of monitoring system and load testing of the Cetina bridge near Trilj in south of Croatia. The main superstructure of the bridge is a concrete arch of a box-shaped cross section. The deck’s superstructure is a grillage concrete structure over ten spans. The design of the bridge anticipated a permanent observation of the structure in exploitation. Therefore a permanent monitoring system was installed at the bridge. Monitoring system includes the periodic measuring of displacements, dynamic characteristics and reinforcement corrosion, along with continuous measuring of strains, temperature and humidity. The readings of the periodic measurements are supposed to be quarterly conducted. The measuring of strains, temperature and humidity is being performed continuously at 24 locations. All the sensors are being powered continuously over the solar collector installed near the bridge and the data is being stored to the “data logger”. Load testing of the bridge was conducted in accordance with the Croatian HRN u.m1.046. norm. Static load testing was conducted through 19 load phases. Seven load phases in which the arch was tested (8 trucks) and 12 load phases of the deck structure (4 trucks). During the loading strains were measured in three arch cross sections (impost, quarter of the arch and apex) and in two deck structure cross sections. Strains were measured by 16 LVD T sensors which are a part of the monitoring system. During the load testing displacements were measured in two lines, above all the supports and in the centres of deck structure span. Dynamic testing was conducted in order to determine dynamic parameters of the structure. Dynamic response of the superstructure was recorded during actual mobile load of a heavy truck weighing approximately 32, 0 t. Dynamic parameters are significant for the future diagnostic of structure in exploitation as they are functions of global stiffness of structure and are as such the index of real condition of the structure. Results of experimental testing are compared to theoretical results of FE numerical model. |
