TY - CONF A1 - Wöhlecke, Andreas ED - Egloffstein, Thomas ED - Burkhardt, Gerd T1 - Arbeits- und Diskussionsthemen aus dem Fachbeirat der BAM und von der Zulassungsstelle N2 - Die BAM wurde 2009 u. a. mit der Zulassung von Bewehrungsgittern für den Deponiebau beauftragt. Der Stand von Wissenschaft und Technik bot jedoch keine ausreichende Grundlage, die tatsächlich relevanten Widerstände und die mit diesen Widerständen verbundene Wechselwirkung zwischen Gitter und Boden im Hinblick auf eine mindestens 100-jährige Funktionsdauer realistisch beurteilen zu können. Es wurde daher nur eine vorläufige Zulassungsrichtlinie für diese Produkte erarbeitet. In der Zwischenzeit hat sich ein neuer Kenntnisstand ergeben. Vor diesem Hintergrund hat die AG (Arbeitsgruppe) Geogitter des Fachbeirats der BAM am 26.09.2017 getagt. Es sollen die aktuellen Erkenntnisse und Schlussfolgerungen für die Zulassung in Kürze vorgestellt werden. Die entsprechenden Kapitel beruhen dabei auf einem Arbeitspapier von W.W. Müller und dem Autoren, das der Arbeitsgruppe zur Diskussion vorgelegt wurde. Weiterhin soll über Entwicklungen in Zusammenhang mit Kunststoffdichtungsbahnen (KDB) berichtet werden. Die Anforderungen an die Schweißzusätze für das Extrusionsschweißen wurden angepasst. Zudem soll über die aktuelle Diskussion der Schweißbarkeit unterschiedlicher HDPE Materialien informiert werden. Die maßgebliche DVS (Deutscher Verband für Schweißen und verwandte Verfahren) Richtlinie 2225-4 wird derzeit offenbar so ausgelegt, dass Materialien mit völlig unterschiedlichen Schmelze-Massefließrate miteinander verbunden werden könnten. Dies steht allerdings im grundlegenden Widerspruch zum Stand der Technik. Derzeit gibt es intensive Diskussion über die Entlassung von Deponien aus der Nachsorge. Sind Geokunststoffe in den Böschungen einer Deponie verwendet worden, wäre eine Entlassung aus der Nachsorge demnach im Moment nicht möglich. Die Deponie müsste dafür nach der Deponieverordnung (DepV) u. a. „insgesamt dauerhaft standsicher“ sein. Geokunststoffe erfüllten ihre Funktion über einen Zeitrahmen von mindestens hundert Jahren. Die Dauerhaftigkeit wird bei der Diskussion aber offenbar als „Ewigkeit“ verstanden. Dies stehe somit im Widerspruch – so die Argumentation. Auf dieser Veranstaltung wurde im vergangenen Jahr darüber berichtet. Auch auf dieses Thema wird eingegangen. T2 - Abschluss und Rekultivierung von Deponien und Altlasten - Planung und Bau neuer Deponien CY - Karlsruhe, Germany DA - 18.10.2017 KW - Bewehrungen aus Kunststoff KW - Deponien KW - Schweißen PY - 2017 SN - 978-3-939662-21-1 VL - 32 SP - 61 EP - 76 PB - ICP Eigenverlag Bauen und Umwelt CY - Karlsruhe AN - OPUS4-42595 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Trubiroha, P. ED - Ziegahn, K.-F. T1 - Quantitative Auswertemöglichkeiten bei der spektralen Bestrahlung – Berechnung des Wirkungsspektrums N2 - Für die Bewertung des Wellenlängeneinflusses auf die Alterungsvorgänge bei der Bestrahlung UV- oder lichtempfindlicher Materialien kann die Methode der spektralen Bestrahlung angewendet werden. Im Prinzip wird dabei das linear dispergierte Spektrum einer Strahlenquelle mit kontinuierlichem Spektrum (z.B. Xe-Lampe) auf eine Probenoberfläche abgebildet, so dass Ort einer Materialänderung und Wellenlänge der Bestrahlung einander zugeordnet werden können. Nachfolgende lokal-auflösende Analysemethoden ermitteln eine Eigenschaftsänderung an einem spezifischen Ort der Probe, aus dem sich dann die Bestrahlungswellenlänge ergibt. Der verwendete Aufbau wird beschrieben. Es wird an einem ausgewählten Beispiel gezeigt, wie durch geeignete Anbindung eines Messsystems zur Bestimmung der spektralen Bestrahlungsstärke und ortsaufgelöste Messungen der Eigenschaftsänderungen eine quantitative Auswertung realisiert werden kann. Der Einfluss nichtlinearer Alterungsverläufe wird diskutiert. Grenzen der Methode werden aufgezeigt und Erweiterungsmöglichkeiten dargestellt. T2 - 46. Jahrestagung der GUS CY - Stutensee-Blankenloch, Germany DA - 22.03.2017 KW - UV-Bestrahlung PY - 2017 SN - 978-3-9816286-9-2 SP - V 8, 91 EP - 99 AN - OPUS4-42578 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miccoli, Lorenzo A1 - Silva, R. A. A1 - Garofano, A. A1 - Oliveira, D. V. ED - Papadrakakis, M. ED - Fragiadakis, M. T1 - In-Plane behaviour of earthen materials: A numerical comparison between adobe masonry, rammed earth and cob N2 - The paper presents a comparison between different numerical modelling approaches aiming to simulate the in-plain behaviour of three types of earthen materials, namely adobe masonry, rammed earth and cob. For this purpose, uniaxial and diagonal compression tests were carried out, which allowed determining important mechanical parameters, such as compressive strength, Young’s modulus, Poisson’s ratio, shear strength and shear modulus. Furthermore, the tests allowed assessing the level of non-linear behaviour of the respective stress–strain relationships as well as the failure modes. The experimental results were then used for the calibration of numerical models (based on the finite element method) for simulating the non-linear behaviour of the earth materials under in-plane shear loading. Both macro- and micro-modelling approaches were considered for this purpose. The procedures adopted for model calibration established the reliability of various modelling strategies for the different loading conditions. The simplified Approach based on macromodelling shows a satisfactory accuracy and low computational costs. The results reproducing the uniaxial compression are in good correspondence with the post-elastic behaviour observed in the experimental campaign. The micro-modelling approach adopted to reproduce the shear behaviour, even with higher computational cost, represents a suitable tool to predict the adobe masonry and rammed earth collapse mechanisms. T2 - 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2017) CY - Rhodes, Greece DA - 15.06.2017 KW - Earthen materials KW - Compression behaviour KW - Shear behaviour KW - Digital image corelation KW - Finite element method PY - 2017 SN - 978-618-82844-1-8 VL - 1 SP - 2478 EP - 2504 AN - OPUS4-42579 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miccoli, Lorenzo A1 - Müller, U. A1 - Fontana, Patrick ED - Mazzolani, F. M. ED - Lamas, A. ED - Calado, L. ED - Proenca, J. M. ED - Faggiano, B. T1 - Strengthening of rammed earth structural elements. Mechanical behaviour under shear and cyclic loading N2 - An experimental investigation was carried out to study the in-plane shear behaviour of rammed earth structural elements strengthened with polyester fabric strips. The original idea for the retrofitting with polyester fabric strips was to introduce a vertical element for walls in order to take up horizontal loads resulting in a shear response of the building element. It has to be considered that vertical slits into the walls for fixing the strips are points of weakness and have to be mitigated by the adhesive. In this case a base coat mortar was employed. Strengthened elements were tested to exploit the strength potential of earthen materials and to solve its lack of tensile strength, significantly improving not only strength but also ductility. As part of the study results of a testing campaign of unstrengthened structural elements were considered. Strengthened elements were tested in diagonal compression/shear and cyclic shear-compression. A unique reinforcement orientation was used. The results of these tests are presented in this paper and include the load-displacement behaviours, crack patterns, failure modes. The results showed that the reinforcement was the most effective under cyclic shear-compression tests, with increase in load and displacement capacity observed. Under diagonal compression the reinforcement did not likely contribute significantly to the shear resistance, due to a lack of embedment length of the strips. T2 - 3rd International Conference on Protection of Historical Constructions (PROHITECH 2017) CY - Lisbon, Portugal DA - 12.07.2017 KW - Rammed earth KW - Diagonal compression tests KW - Shear-compression tests KW - Strengthening KW - Polyester fabric strips PY - 2017 SN - 978-989-8481-58-0 SP - 157 EP - 158 PB - IST-Press AN - OPUS4-41263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ferraioli, M. A1 - Miccoli, Lorenzo A1 - Abruzzese, D. ED - Mazzolani, F. M. ED - Lamas, A. ED - Calado, L. ED - Proenca, J. M. ED - Faggiano, B. T1 - Seismic risk assessment of the Santa Maria a Vico bell tower. Ambient vibration measurements and numerical model tuning N2 - The paper investigates the dynamic characterisation along with the numerical model tuning and the seismic risk assessment of a monumental masonry tower in Italy namely the Santa Maria a Vico bell tower. Full-scale ambient vibration tests were performed under the impact of environmental loads. The technique of modal extraction in the frequency domain was applied. In-situ investigation survey was used in calibrating the refined 3D finite element model. The FEM tuning was carried out by varying the mechanical parameters and accounting for the restraint offered by the neighbouring buildings and the role of soil–structure interaction. The paper shows that the modal identification is a reliable technique that can be used in-situ for assessing the dynamic behaviour of monumental buildings. The tuned FEM model of the tower was usefully employed to determine the theoretical fundamental frequencies, which accurately fit the experiment data. Finally, the seismic performance of the bell tower was assessed using a non-linear static procedure based on the multi-modal pushover analysis and the capacity spectrum method. The results confirm that seismic events of moderate intensity can produce heavy damage to the masonry tower presented in this study. T2 - 3rd International Conference on Protection of Historical Constructions (PROHITECH 2017) CY - Lisbon, Portugal DA - 12.07.2017 KW - Masonry tower KW - Ambient vibration tests KW - Dynamic characterisation KW - Seismic assessment PY - 2017 SN - 978-989-8481-58-0 SP - 159 EP - 160 PB - IST-Press AN - OPUS4-41279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paul, Niels A1 - Hüllmann, Dino A1 - Kohlhoff, Harald A1 - Neumann, Patrick P. ED - Cosmi, F. T1 - A concept for an aerial-based landfill monitoring system N2 - Aerial based robots constitute a safe and suitable approach to remote gas-sensing. This paper describes a new concept , incorporating existing UAVs and newly developed gas sensors. The presented autonomous system is able to perform gas source localization and gas distribution mapping. T2 - 34th Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Trieste, Italy DA - 19.09.2017 KW - Gassensor KW - Multicopter KW - UAV KW - Olfaction PY - 2017 SN - 978-88-8303-863-1 SP - 179 EP - 181 PB - University of Trieste, Italy CY - Trieste, Italy AN - OPUS4-42122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Trubiroha, P. T1 - Evaluation of outdoor exposures by means of exposure response functions N2 - Outdoor exposure tests are a common tool to evaluate the weathering resistance of a polymeric material or component. However, they have only a limited validity, mainly due to the limited reproducibility of the weather as well as of the bad adaptability to other exposure sites. Typically, an outdoor exposure is characterized by the measured radiant exposure; sometimes averaged temperature data are added. These can be – separately – related to long-term annual means, to get an idea on the severity of the exposure. However, as for polymeric ageing, irradiance and temperature act simultaneously, such severity of an outdoor exposure could be better described by a computed property change of a similar material, which is calculated from the hourly irradiance and temperature values on the base of established exposure response functions. In this way, various outdoor exposures are evaluated. For several exposure sites, annual deviations of the ageing amount are related to annual mean values, to evaluate the weathering reproducibility at the exposure site. Additionally, correlations to relevant weather parameters are illuminated. Also some specific exposure conditions, such as tilt angle, are tested. Compared to the use of weathering reference materials, this procedure unfavourably depends on the availability of a suited control as well as on the quality of the established exposure response function. In contrast, it enables a later exposure evaluation, on the base of documented weather data, if for instance no reference material was exposed. T2 - 8th European Weathering Symposium CY - Vienna, Austria DA - 20.09.2017 KW - Weathering KW - Service life prediction KW - Photodegradation PY - 2017 SN - 978-3-9818507-1-0 VL - 18 SP - 127 EP - 135 PB - Thomas Würtz Grafik Design CY - Karlsruhe AN - OPUS4-42126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trubiroha, P. A1 - Geburtig, Anja A1 - Wachtendorf, Volker T1 - Natural versus artificial weathering of polymers – main differences in climatic conditions N2 - Different climatic conditions and weather variables during natural and artificial exposure of polymers may be reasons for an unsatisfying correlation between the ageing results. Here the main differences are discussed for: - Global solar radiation In weathering devices there is a constant spectral irradiance which is 5 times higher than the averaged spectral irradiance outdoors, which is strongly varying in its diurnal course. Intensified weathering using Fresnel reflectors concentrates only the direct solar radiation with a relatively low UV proportion. Problems of reciprocity may arise from the different mean of irradiance levels. - Temperatures at specimen surfaces. Because of the high irradiance levels mentioned above, artificial exposures may lead to high surface temperatures and large temperature differences between differently coloured specimen surfaces, if the artificial radiation source emits much VIS- and IR-radiation. Outdoors the surface temperature and temperature differences of exposed specimens are influenced by considerably lower irradiance levels and additionally by an effective radiation loss in the night. - Relative humidity at specimen surfaces In weathering devices the relative humidity at specimen surfaces is very low if it is uncontrolled. If controlled by ultrasonic humidifiers or spray nozzles, the additional exposure to water droplets is quite likely. - Wetness on specimen surfaces All usual spray programs prescribed in weathering standards recommend frequently changing of short spray/dry periods and result in total times of wetness (TOW) of the exposed specimen surfaces which is only about 30 % of the outdoor TOW. - Acidic precipitation and bio films Acidic precipitation and bio films are usual outdoor conditions which are only considered in special weathering tests. T2 - 8th European Weathering Symposium CY - Vienna, Austria DA - 20.09.2017 KW - Artificial weathering KW - Natural weathering KW - Weathering parameters PY - 2017 SN - 978-3-9818507-1-0 VL - 18 SP - 63 EP - 75 CY - Karlsruhe AN - OPUS4-42127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wöhlecke, Andreas ED - Kim, Bumjoo ED - Kim, Yun-Tae ED - Hong, Gigwon ED - Jung, Young-Hoon ED - Chong, Song-Hun T1 - The “zero leakage” approach and German regulations for geosynthetics used in landfill liner and capping systems N2 - An approach to achieve “zero leakage” is discussed with respect to the experience in Germany, where strict regulations for landfill lining and capping systems have been developed and issued because of large environmental problems related to landfills that accumulated in the 1970’s and 1980’s. These regulations for landfills and geosynthetics which are used in landfill liner and capping systems are shortly described. The main certification requirements for the products as well as conclusions for their use are presented. Using a thick, high quality HDPE geomembrane (GMB), which is installed free of residual waves and wrinkles in intimate contact with a compacted clay liner (CCL) or geosynthetic clay liner (GCL) of very low permeability, by a qualified, experienced, well equipped and properly third‐party controlled installer and which are protected by heavy protection layers designed with respect to long‐term performance of the GMB, may result in a liner or capping system of practically no leakage. This is demonstrated by analyzing results of measurements obtained from permanently installed leak detection systems in combination with HDPE GMBs. T2 - 11th International Conference on Geosynthetics CY - Seoul, Korea DA - 16.09.2018 KW - HDPE geomembrane KW - Landfill liner KW - Leak detection KW - Regulations PY - 2018 VL - 11 SP - 1 EP - 8 AN - OPUS4-46030 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Tracks with under-ballast plates and their mitigation of train induced ground vibration N2 - Experiments have been performed at a test site with six different tracks with under-ballast plates. Hammer excitations of the soil and the tracks as well as train passages have been measured. The experimental observations are as follows. 1. The natural soil is stiff gravel whereas the railway dam consists of softer material. 2. The track compliance indicates a soft ballast if no train is present to provide a confining pressure. 3. The track response to the train passages can be split into a low-frequency region which is ruled by the static loads and a high-frequency region which is ruled by dynamic loads. 4. The track responses to hammer and track excitation indicate the presence of many voids between the sleepers and the ballast. 5. The ground vibrations are highly influenced by the soil. Due to the stiff soil at the site, the hammer and train induced spectra have a considerable high-frequency content. 6. A reduction of the ground vibration has been observed in a low-frequency range. The mitigation effects of an under-ballast plate are also investigated by calculations of a wavenumber domain model. The under-ballast plate has an effect at low frequencies where it distributes the static load over a longer track section. The impulse of the axle passage is longer and the frequencies are lower due to the plate stiffness. The axle impulses could yield a low-frequency ground vibration in an irregular soil with a randomly varying stiffness. This low-frequency part of the ground vibration (the scattered axle impulses) seem to be reduced by the under-ballast plate. T2 - 24th International Congress on Sound and Vibration CY - London, UK DA - 23.7.2017 KW - Railway vibration KW - Ballast tracks KW - Under-ballast plate KW - Ground vibration PY - 2017 SP - 1 EP - 8 PB - IIAV CY - Auburn, USA AN - OPUS4-42091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -