TY - JOUR A1 - Hu, W.-H. A1 - Said, Samir A1 - Rohrmann, R. A1 - Cunha, À. A1 - Teng, J. T1 - Continuous dynamic monitoring of a prestressed concrete bridge based on strain, inclination and crack measurements over a 14-year span JF - Structural Health Monitoring N2 - The Westend Bridge is located on the A100 Highway in Berlin. An integrated continuous dynamic monitoring system, composed of 20 velocity sensors, 5 temperature sensors, 3 strain gauges, 1 crack sensor and 2 inclination sensors, was implemented by the Federal Institute for Materials Research and Testing in 2000. The system runs continuously with occasional intermittence and led to a huge amount of data over a 14-year span. In this article, variations of the strain, crack and inclination measurements during the last 14 years are presented. It is noted that the observed crack and inclination of the bridge are strongly influenced by seasonal temperature variation. It further induces change in the relationship between the strains measured in both concrete and prestressed tendon. Application of k-means cluster Analysis technique in both the crack and strain measurements can partition them into different seasonal phases by identifying ‘turning points’ that indicate annual periodical bridge change. In the period of these two ‘turning points’, a strong linear relation of the strains in two materials is observed. In the rest of the year, a nonlinear relationship between the strains recorded in both the concrete and the prestressed tendon is noted. The possible reason is the additional thermal load due to the change in temperature difference between the bridge’s surface and soffit. Finally, a health index in a Framework of regression model and process control theory is proposed by investigating the linear relationship between the strains in concrete and prestressed tendon. The tendency of the health index in the 14 years may suggest the long-term bridge change during that time frame. KW - Detection of structural change KW - Structural health monitoring KW - Strain KW - Crack KW - Inclination KW - Bridge PY - 2017 DO - https://doi.org/10.1177/1475921717735505 VL - 17 IS - 5 SP - 1073 EP - 1094 PB - SAGE CY - USA/UK AN - OPUS4-45990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, W. A1 - Said, Samir A1 - Rohrmann, R. A1 - Teng, J. A1 - Li, Z. A1 - Lu, W. A1 - Cunha, A. T1 - Operational modal analysis and continuous dynamic monitoring of structures T2 - Fundamental Research in Structural Engineering: Retrospective and Prospective, Vols 1 and 2 N2 - This paper addresses operational modal analysis (OMA) and continuous dynamic monitoring (CDM) of two bridges. One of them is installed with Tuned Mass Dampers (TMDs) while another one is a normal bridge. Two ambient vibration tests were performed on these two bridges respectively. It is observed that not only installation of TMDs but also environmental factors influence the variations of structural frequencies, which may mask the subtle change induced by small structural changes. As a result, continuous dynamic monitoring systems were implemented on these two bridges, in order to evaluate efficiency of the TMD system, remove the environmental effects and build reliable damage indices that are only sensitive to structural changes. The results of CDM of these two bridges during several years are presented. Software systems developed for OMA and CDM are also introduced. T2 - 14th International Symposium on Structural Engineering (ISSE-14) CY - Beijing, Peoples Republic of China DA - 12.10.2016 KW - Structure KW - Operational modal analysis KW - Continuous dynamic monitoring PY - 2016 SN - 978-7-03-050125-7 VL - 2016 SP - 366 EP - 372 PB - Science Press Beijing AN - OPUS4-38876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -