Modeling and long term structural health monitoring of Villanueva del Jalon viaduct

摘要

Villanueva del Jalon viaduct is a high-speed railway bridge located at Calatayud, Spain, composed of a pre-stressed concrete box girder with 6 spans and 5 piers measuring a total length of 250 m. Within the framework of the VIADINTEGRA research project funded by both the Spanish Ministry of Economy and Competitivity and the European Union, itiis viaduct is being permanently monitored. The evaluation of the dynamic behaviour of the structure by vibration measurement has been studied during the last two years. Estimation of modal parameters from vibration data obtained in operational conditions has been used to update FE models of the structure and evaluate seasonal changes in modal properties. Data from a short term vibration measurement campaign and long term permanent monitoring have been used in this work. Well correlated models of the structure in its healthy state have been obtained and have demonstrated to be an useful instrument in the prediction of both the time histories of accelerations and the maximum levels of vertical acceleration in the bridge under the action of railway traffic. The analysis of the evolution of first natural frequencies of the bridge indicates that they follow the main trends of the temperature data. This correspondence of trends is especially clear in the case of averaged value of frequencies for the first five vertical modes. Updated models have been also used to evaluate the change in modal properties and dynamic response of the structures under the effect of simulated damage scenarios, and results confirm that normal changes caused by varying environmental factors may mask the variations due to structural damage.