Dynamic monitoring of an old long concrete bridge

• DOI: https://doi.org/10.22533/at.ed.5632402023

• Palavras-chave: Ensaios dinâmicos; ponte antiga de concreto; vibrações; acelerômetros; análise modal

• Keywords: Dynamic tests; old concrete bridge; vibrations; accelerometers, modal analysis

• Abstract: This paper presents the dynamic monitoring carried out on a 458 m long, 38 m high, Papagaios Bridge, State of Paraná. This is a concrete arch bridge built over 60 years ago, which needed repairs. The dynamic monitoring was designed to carry out a structural integrity assessment and to calibrate a numerical model to be used for the structural rehabilitation design. Vibration measurements were carried out on the bridge in selected locations. This paper addresses data analysis, the impact measurements when a train enters the bridge and modal analysis. An important aspect was the measurements taken at the entrance to the bridge before and after emergency repairs, allowing analysis of the coefficient of impact before and after the repairs. In addition, the analysis of the frequency calibrated numerical model led to conclusions about the necessary structural reinforcement, that is, the need for reinforcement in the deck and pillars. The decks were reinforced using carbon fibre. Ballast had to be removed and reinforcement applied. Reinforcing the pillars was much simpler than originally expected. The analysis clearly showed that the pillars lacked structural stiffness. This was achieved simply by reinforcing at many positions along their heights, surrounding them with welded steel L sections.