TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - Measurements comparing the damaged and the repaired status of the same track section at different times, or a damaged and an intact track section at the same time have been successfully performed and compared with the theoretical behavior of intact and damaged tracks. The loose of contact between the sleeper and the plate, between the plate and the base layer, due to train passages and hammer impacts, have been investigated. T2 - 7th International Symposium on Environmental Vibration and Transportation Geodynamics CY - Hangzhou, China DA - 28.10.2016 KW - Railway track KW - Slab track KW - Field tests KW - Track damage monitoring KW - Finite element method KW - Boundary element method PY - 2016 AN - OPUS4-38275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - The damage detection and repair control have become important tasks for ballast and slab tracks. Measurements which compare the damaged and the repaired status of the same track section at different times, or which compare a damaged and an intact track section at the same time, have been successfully performed at some sites in Germany with slab tracks and ballast tracks and compared with the theoretical behaviour of intact and damaged tracks. The loss of contact between the sleeper and the plate, between the plate and the base layer, and some problems with soft or weakened soil have been analysed. The observed results, changes in the time histories of displacements and velocities due to train passages and in the transfer functions (compliances) due to hammer impacts, are encouraging that these measurements can be used to detect track damage. In addition, calculations with the combined finite-element boundary-element method have been used to confirm the conclusions about intact or damaged railway tracks. T2 - 7th International Symposium on Environmental Vibration and Transportation Geodynmaics CY - Hangzhou, China DA - 28.10.2016 KW - Railway track KW - Slab track KW - Ballast track KW - Track-soil interaction KW - Field tests KW - Track damage monitoring KW - Finite element method KW - Boundary element method PY - 2016 SP - 3 EP - 19 AN - OPUS4-38261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir T1 - Structural health monitoring by division 7.2, buildings and structures N2 - BAM is one of the pioneers in Germany and Europe regarding the monitoring of civil structures. BAM-Division 7.2 operates its monitoring systems with sophisticated components for data acquisition and data analysis, which can be flexibly adapt to the respective structure and measuring tasks. The BAM monitoring systems have been operated on numerous bridges (steel, concrete, pre-stressed concrete and masonry), buildings, towers, masts, monuments, wind turbines and other structures. In 1999, BAM established a national standard 'Automated continuous monitoring in civil engineering'. This has been internationalized within the framework of the EU research project SAMCO "F08b Guideline for Structural Health Monitoring". BAM-Division 7.2 is interested in international cooperation with Chinese partners. T2 - SEMINARS AT SHENZHEN GRADUATE SCHOOL OF HIT CY - Shenzhen, China DA - 02.11.2016 KW - Structural health monitoring (SHM) KW - Load-carrying capacity KW - Structural analyses KW - Damage detection PY - 2016 AN - OPUS4-38277 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 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 - TY - CONF A1 - Baeßler, Matthias A1 - Hille, Falk A1 - Said, Samir ED - Baeßler, Matthias ED - Rogge, Andreas ED - Möller, Gerd ED - Schiefelbein, Norbert T1 - Bauwerksüberwachung von Brücken im Kontext saisonaler Einflüsse N2 - Anhand verschiedener Bespiele wird diskutiert, wie Temperaturbeanspruchungen in einer Bauwerksüberwachung sichtbar werden und wie sie zu bewerten sind. Insbesondere der Einfluss auf die Zustandsbewertung im Sinne der Standsicherheit stellt häufig eine große Schwierigkeit dar. Behelfsweise besteht eine grundlegende Möglichkeit darin, ein Tragwerk immer zu seiner schwächsten Phase, d.h. in der Regel im Sommer zu beurteilen. Wie aufgezeigt, können zudem statistische Verfahren geeignet sein, Tragfähigkeitsänderungen zu detektieren. Als wesentliche Zukunftsaufgaben werden verbesserte Detektionsalgorithmen und physikalisch begründete Modelle zum mechanischen Verhalten angesehen. Die Akzeptanz schwingungsbasierter Verfahren zur Detektion und Lokalisierung von Schäden in der praktischen Anwendung ist alleinig von der Fähigkeit abhängig, Einflüsse aus veränderlichen Umwelt- und Betriebsbedingungen, insbesondere aber die aus der Temperatur zu eliminieren. Da die in den letzten Jahren immer wichtiger werdenden stochastischen Verfahren zur Schadensde-tektion und -lokalisierung die (statistische) Charakteristik der Messdaten bereits implizit nutzen, sind hier Entwicklung, Anpassung und Anwendung statistischer Algorithmen zur Eliminierung der variierenden Umwelteinflüsse naheliegend. Auf der anderen Seite wird der saisonale Einfluss auf Bauwerksmessungen in sehr vielen Veröf-fentlichungen dargestellt und es werden häufig verdachtsweise begründete physikalische Zu-sammenhänge für das Verhalten aufgezeigt. Im Regelfall sind die Aussagen aber nicht experi-mentell überprüft und von eher allgemeiner Natur („Asphalt reagiert temperaturabhängig“). Ob-jektspezifische Zusammenhänge, beispielsweise über Versuch an Repräsentanten in der Klima-kammer ermittelt, könnten jedoch sehr hilfreich sein. T2 - Messen Im Bauwesen CY - BAM, Berlin, Germany DA - 08.11.2016 KW - Bauwerksüberwachung KW - SHM KW - Temperatureinfluss PY - 2016 SN - 978-3-9817853-6-4 VL - 2016 SP - 89 EP - 102 PB - Eigenverlag BAM AN - OPUS4-39354 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -