TY - CONF A1 - Helmerich, Rosemarie T1 - Practical applications of recent BAM-research results of NDT and monitoring in civil engineering N2 - Nondestructive testing and monitoring was of mayor interest in BAM-research related to the survey of civil engineering structures during the last two decades. Three case studies about research projects carried out at BAM were presented. All three projects focussed on the survey of parameters and safety related tasks in bridge engineering and inspection. First, the monitoring of the Berlin main station was presented with focus on the sensors developed specifically for this project. The second case study presented and application of guided ultrasonic waves to CFRP-strengthened bridges. The method was sucsessully applied to two of four different strengthening measures carried out min. 10 years ago. The last project presented the feasibility study of a network consisting of simple Bluetooth modules to survey changes in the moisture content in sand and massive concrete. T2 - Workshop CY - University of New South Wales, Sydney, Australia DA - 17.07.2018 KW - Monitoring KW - Wireless sensor network (WSN), KW - NDT KW - Guided waves KW - Bluetooth modules KW - Inspection KW - Civil infrastructure PY - 2018 AN - OPUS4-45657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens T1 - Bond durability of CFRP-laminates on concrete bridges N2 - Trans-European corridors for transport of people and goods require strengthening of bridges to carry increased axle loads in terms of absolute axle loads and of their frequency. Most of the bridges along highways are reinforced or prestressed concrete bridges. Since the late 1990s, CFRP laminates have been applied to box girder and T-beam bridges to increase the overall capacity. Although regular inspections are carried out, no special method was available to test the bond condition of CFRP laminates after being in Service for more than ten years. The German Center of Competence in Civil Engineering is aware of this need and funded a research project to investigate the bond condition by means of advanced non-destructive testing (NDT). T2 - 31st Danubia-Adria Symposium on advances in experimental mechanics CY - Kempten, Germany DA - 24.09.2014 KW - Concrete bridges KW - Strengthening KW - Non-destructive testing KW - CFRP KW - Durability KW - Inspection PY - 2014 SN - 978-3-00-046740-0 SP - 1 EP - 2 AN - OPUS4-33116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens T1 - Non-destructive detection of surface-bond defects in carbon composite-strengthened concrete structures N2 - For almost 15 years, carbon fibre-reinforced polymer (CFRP) plates and sheets have been used for strengthening and repair of civil engineering structures. CFRP plates were applied to upgrade structures for change in use or increasing traffic load. CFRP laminates have also been used to repair deteriorated structures such as multi-storey parking or bridges. The execution quality and condition of the strengthening measure in terms of bond integrity were neither monitored nor tested systematically. Inspectors eventually applied simple hammer knocking during regular main inspection for subjective noise distinction as a measure for eventual insufficient bond. This paper presents the feasibility and the limitations of low-frequency transversal ultrasonic waves with dry-coupling point-contact sensors for inspection and defect detection between CFRP laminate and concrete surfaces. The German Centre of Competence in Civil Engineering (DIBt) has initiated a national research project [Helmerich et al. (2012). Condition analysis of bonded CFRP-applications on concrete structures by means of non-destructive testing [in German: Zustandsuntersuchung von CFK-Klebeverstärkungen an Betonbauteilen mittels zerstörungsfreier Prüfung (ZfP)]. Final, internal project report], carried out at the Federal Institute for Materials Research and Testing (BAM), Germany. The aim of the project was to present a potential non-destructive testing method for bond defect detection as a measure for the durability of the strengthening system more than 10 years after application. KW - Concrete bridges KW - Strengthening KW - Non-destructive testing KW - Composite materials KW - Durability KW - Inspection PY - 2015 DO - https://doi.org/10.1080/15732479.2013.879322 SN - 1573-2479 VL - 11 IS - 1 SP - 3 EP - 14 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-33086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Wiggenhauser, Herbert T1 - Non-destructive testing of concrete structures T2 - 4th International Conference on Advances in Mechanical Engineering and Mechanics (ICAMEM2008) CY - Sousse, Tunisia DA - 2008-12-16 KW - Non-destructive testing KW - Civil engineering KW - Inspection KW - Knowledge transfer KW - Case study PY - 2008 SP - 1 EP - 10 AN - OPUS4-18655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kammel, C. A1 - Helmerich, Rosemarie ED - Jan Bien, ED - Lennart Elfgren, ED - Jan Olofsson, T1 - Inspection of steel bridges KW - Inspection KW - Steel bridges KW - Zerstörungsfreie Prüfung KW - Engineering critical Assessment PY - 2007 SN - 978-83-7125-161-0 SP - 127 EP - 136 PB - Dolnoslaskie Wydawnictwo Edukacyjne CY - Wroclaw, Poland AN - OPUS4-16093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Milmann, Boris A1 - Wöstmann, Jens A1 - Feistkorn, S. ED - Barros, J. ED - Sena-Cruz, J. T1 - Durability of CFRP-laminate strengthening N2 - First bridge structures have been strengthened by means of Carbon-Fiber-Reinforced-Polymer (CFRP)-laminates extemally glued to the concrete surface in the last two decades. At present there is no Information about the durability of these Systems after having been in Service for more than ten years. The paper presents laboratory tests and case studies with automated non-destructive testing to analyse the current bond condition of extemally bonded CFRP-laminates to concrete structures, strengthened about ten years ago. The paper presents the feasibility and the limitations of ultrasonic inspection of selected areas of CFRP-laminate-strengthened structures co-funded by the German Center of Competence in Civil Engineering (DIBt) in a national project. Areas of interest were the end region of laminates or areas with educated doubts about their bond integrity selected and marked in the inspection records during main inspections. In a feasability study, the functionality of the ultrasonic test for bond evaluation below CFRP-laminates without any surface protection measure, was confirmed by testing a CFRP-laminate strengthened slab with artificial voids in a blind laboratory test with an accuracy of + 1 cm. The accuracy depends on the step width, line interspace and the distance between ultrasonic transducer and receiver. This accuracy suits a measuring grid of 1 cm. The case studies consider flexural strengthening and repair of prestressed concrete structures as well as longitudinal and transverse strengthening of bridge slabs with simple reinforcement. Both alternatives were considered, covered with mineral surface protection layer and without. The measurement results of automated scanned surfaces is presented in color-codes images. In the tested areas with no or thin surface protection the non-destructive inspection did not uncover severe defects or Deterioration processes. None the less, proposals for further research is given, in testing of the acceptable bond defects and in advancing the ultrasonic test including the devlopment of sensors for this application. T2 - FRPRCS-11 - 11th International symposium on fiber reinforced polymer for reinforced concrete structures CY - Guimaraes, Portugal DA - 26.06.2013 KW - CFRP-Laminate KW - Debonding KW - Flexural strengthening KW - Bridge KW - NDT KW - Durability test KW - Inspection PY - 2013 SN - 978-972-8692-84-1 SP - 41 EP - 42 (Session 6.5) AN - OPUS4-28859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -