TY - CONF A1 - Viefhues, Eva A1 - Döhler, M. A1 - Hille, Falk A1 - Mevel, L. ED - Simani, S. ED - Patan, K. T1 - Asymptotic analysis of subspace-based data-driven residual for fault detection with uncertain reference N2 - The local asymptotic approach is promising for vibration-based fault diagnosis when associated to a subspace-based residual function and efficient hypothesis testing tools. It has the ability of detecting small changes in some chosen system parameters. In the residual function,the left null space of the observability matrix associated to a reference model is confronted to the Hankel matrix of output covariances estimated from test data. When this left null space is not perfectly known from a model, it should be replaced by an estimate from data to avoid model errors in the residual computation. In this paper, the asymptotic distribution of the resulting data-driven residual is analyzed and its covariance is estimated, which includes also the covariance related to the reference null space estimate. The advantages of the data-driven residual are demonstrated in a numerical study, and the importance of including the covariance of the reference null space estimate is shown, which increases the detection Performance. T2 - 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2018 CY - Warsaw, Poland DA - 29.08.2018 KW - Subspace-based method KW - Fault detection KW - Uncertainty in reference KW - Residual evaluation KW - Statistical tests KW - Vibration measurements PY - 2018 U6 - https://doi.org/10.1016/j.ifacol.2018.09.610 SN - 2405-8963 VL - 51 IS - 24 SP - 414 EP - 419 PB - Elsevier AN - OPUS4-46303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Ternary mix design of grout material for structural repair using statistical tools N2 - Repair is an indispensable part of the maintenance of structures over their lifetimes. Structural grouting is a widely used remediation technique for concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. A structural grout system should be injectable in narrow spaces and hence include ingredients with finer particles. Ultrafine cements are ideal for these type of demanding grouts due to their superior properties compared to that of the less expensive, but coarser ordinary Portland cement (OPC). Supplementary cementitious materials (SCMs) are often used to replace OPC clinker based binder in order to modify certain properties and to reduce costs. The most commonly used SCMs are fly ash (FA), and ground granulated blast furnace slag (GGBS). For various special applications microsilica (MS), and metakaolin (MK) are also used. Identifying the optimum replacement contents of OPC by SCMs are a challenge during the design of such grouts. The aim of this experimental study is to investigate the effect of the selected SCMs (FA, MS and MK) on the slump flow, time of efflux, viscosity, shrinkage, and compressive and flexural strength of ultrafine cement based grouts with constant water-binder ratio and superplasticizer content. The test program was formulated using Box-Behnken design principles. Maximum percentages of replacement with ultrafine cement was 6% by volume of cement for MS and 16% for FA, and MK. The results suggest that most investigated grouts have the potential to be used for structural applications. The appropriate quadratic models are then formulated through statistical tools and presented as response surfaces. The trends indicate that fly ash improves the rheological properties, whereas microsilica and metakaolin positively affect shrinkage and mechanical properties to some extent. Based on the influence of SCMs and priorities among the properties, Decision Matrix Analysis (DMA) is carried out to select the most suitable ones among the SCMs. The analysis suggests that microsilica and fly ash are more suitable as SCMs than metakaolin without affecting the properties. KW - Grouting KW - Microsilica KW - Fly ash KW - Metakaolin KW - Workability KW - Viscosity KW - Strength KW - Mix design KW - Box-Behnken KW - Decision matrix analysis PY - 2018 U6 - https://doi.org/10.1016/j.conbuildmat.2018.08.156 SN - 0950-0618 SN - 1879-0526 VL - 189 SP - 170 EP - 180 PB - Elsevier Ltd. AN - OPUS4-45922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwedler, Michael A1 - Dörfeldt, Stefan A1 - Lüddecke, Falk A1 - Seidel, Marc A1 - Thiele, Marc ED - Kurrer, Karl-Eugen T1 - Einflussfaktoren auf die Vorspannkraft von Schrauben mit Durchmessern bis M72 in Ringflanschverbindungen T1 - Factors influencing the pretension force in bolts with diameter up to M72 in ring flange connections N2 - Bei Monopfahlgründungen von Offshore-Windenergieanlagen wird die Verbindung zwischen Monopfahl und Übergangsstück als geschraubter Ringflansch ausgeführt. Die zunehmende Leistungsfähigkeit der Windenergieanlagen führt zu immer größeren Schnittgrößen in diesem Anschluss. In der Folge erhöhen sich nicht nur die Querschnittsabmessungen, sondern es kommen auch zunehmend größere Schrauben zum Einsatz. Da die einschlägigen Regelwerke zur Bemessung dieser Verbindungen nicht für Schrauben der Größen M64 oder M72 konzipiert wurden, stellt sich die Frage der Übertragbarkeit auf solche Anwendungsfälle. Im Rahmen des Aufsatzes werden Einflüsse diskutiert, die eine Herabsetzung der Schraubentragfähigkeit verursachen könnten. Diese Einflüsse, vornehmlich geometrische Imperfektionen, werden systematisch untersucht und ergänzend in praxisrelevanten Beispielen bewertet. Die somit gewonnenen Erkenntnisse werden für die abschließende Beurteilung der großen Schrauben in Ringflanschverbindungen herangezogen. KW - Ermüdung KW - Vorspannung KW - Imperfektion KW - Offshore KW - Windenergieanlage KW - Schrauben PY - 2018 U6 - https://doi.org/10.1002/stab.201810571 SN - 0038-9145 SN - 1437-1049 VL - 87 IS - 2 SP - 149 EP - 161 PB - Wilhelm Ernst und Sohn CY - Berlin AN - OPUS4-44285 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reimold, W. U. A1 - Crosta, A. P. A1 - Hasch, M. A1 - Kowitz, Astrid A1 - Hauser, N. A1 - Sanchez, J. P. A1 - Simoes, L. S. A. A1 - de Sanchez, G. J. A1 - Zaag, P. T. T1 - Shock deformation confirms the impact origin for the Cerro do Jarau, Rio Grande do Sul, Brazil, structure N2 - Cerro do Jarau is a conspicuous, circular morpho‐structural feature in Rio Grande do Sul State (Brazil), with a central elevated core in the otherwise flat “Pampas” terrain typical for the border regions between Brazil and Uruguay. The structure has a diameter of approximately 13.5 km. It is centered at 30o12′S and 56o32′W and was formed on basaltic flows of the Cretaceous Serra Geral Formation, which is part of the Paraná‐Etendeka Large Igneous Province (LIP), and in sandstones of the Botucatu and Guará formations. The structure was first spotted on aerial photographs in the 1960s. Ever since, its origin has been debated, sometimes in terms of an endogenous (igneous) origin, sometimes as the result of an exogenous (meteorite impact) event. In recent years, a number of studies have been conducted in order to investigate its nature and origin. Although the results have indicated a possible impact origin, no conclusive evidence could be produced. The interpretation of an impact origin was mostly based on the morphological characteristics of the structure; geophysical data; as well as the occurrence of different breccia types; extensive deformation/silicification of the rocks within the structure, in particular the sandstones; and also on the widespread occurrence of low‐pressure deformation features, including some planar fractures (PFs). A detailed optical microscopic analysis of samples collected during a number of field campaigns since 2007 resulted in the disclosure of a large number of quartz grains from sandstone and monomict arenite breccia from the central part of the structure with PFs and feather features (FFs), as well as a number of quartz grains exhibiting planar deformation features (PDFs). While most of these latter grains only carry a single set of PDFs, we have observed several with two sets, and one grain with three sets of PDFs. Consequently, we here propose Cerro do Jarau as the seventh confirmed impact structure in Brazil. Cerro do Jarau, together with Vargeão Dome (Santa Catalina state) and Vista Alegre (Paraná State), is one of very few impact structures on Earth formed in basaltic rocks. KW - Serra da cangalha KW - Recovery experiments KW - Piaui state KW - Santa-marta KW - Features KW - Pressure KW - GPA KW - Sandstone KW - Geology PY - 2018 U6 - https://doi.org/10.1111/maps.13233 SN - 1086-9379 VL - 54 IS - 10 SP - 2384 EP - 2394 PB - Wiley AN - OPUS4-50029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Tang, De-Hui A1 - Teng, Jun A1 - Said, Samir A1 - Rohrmann, Rolf T1 - Structural health monitoring of a prestressed concrete bridge based on statistical pattern recognition of continuous dynamic measurements over 14 years N2 - This work describes a vibration-based structural health monitoring of a prestressed-concrete box girder bridge on the A100 Highway in Berlin by applying statistical pattern recognition technique to a huge amount of data continuously collected by an integrated monitoring system during the period from 2000 to 2013. Firstly, the general condition and potential damage of the bridge is described. Then, the dynamic properties are extracted from 20 velocity sensors. Environmental variability captured by five thermal transducers and traffic intensity approximately estimated by strain measurements are also reported. Nonlinear influences of temperature on natural frequencies are observed. Subsequently, the measurements during the first year are used to build a baseline health index. The multiple linear regression (MLR) method is used to characterize the nonlinear relationship between natural frequencies and temperatures. The Euclidean distance of the residual errors is calculated to build a statistical health index. Finally, the indices extracted from the following years gradually deviate; which may indicate structural deterioration due to loss of prestress in the prestressed tendons. KW - Bridge KW - Structural health monitoring KW - Statistical pattern recognition KW - Temperature effect PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-468126 SN - 1424-8220 VL - 18 IS - 12 SP - 4117, 1 EP - 28 PB - MDPI CY - 4052 Basel, Schweiz AN - OPUS4-46812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Peter A1 - Cuéllar, Pablo A1 - Hüsken, Götz A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Insights into compaction grouting for offshore pile foundations N2 - The authors are currently investigating the possibility to apply compaction grouting for offshore pile foundations (Jacket piles as well as monopiles) as a possible retrofitting technique for an optimised foundation concept. In this research project, we are developing a design approach aiming to predict the ideal amount and properties of a grout for a specific soil situation and desired improvement of pile bearing capacity after Installation and during service time. Both numerical and experimental tests have been carried out to investigate the injection process during which a highly viscous grout is injected into the soil under high pressure to displace and compact the surrounding soil without fracturing it. The implicit Material Point Method (MPM) based on a mixed formulation is the numerical technique chosen to deal with the expected large deformations and the arbitrary shape of the developing grout bulb. The usage of MPM prevents both the need of remeshing and the numerical instability induced by extensive mesh distortion. For validation with experimental results, we have constructed a testing chamber with one transparent sidewall. This chamber enables us to observe the injection process directly at the transparent vertical window and to measure the in-plane soil displacements and strains by means of the Digital Image Correlation (DIC) technique. The results already reveal the interrelation of soil and grout properties for a successful usage of this common ground improvement technique. T2 - 37th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2018) CY - Madrid, Spain DA - 18.06.2018 KW - Offshore pile foundation KW - Compaction grouting KW - Material Point Method (MPM) KW - Mixed formulation KW - Digital Image Correlation (DIC) PY - 2018 SN - 978-0-7918-5130-2 SN - 2153-4772 VL - 9 SP - V009T10A013, 1 EP - 9 AN - OPUS4-46004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Döhler, Michael A1 - Hille, Falk A1 - Mevel, Laurent ED - Ottaviano, Erika ED - Pelliccio, Assunta ED - Gattulli, Vincenzo T1 - Vibration-based monitoring of civil structures with subspace-based damage detection N2 - Automatic vibration-based structural health monitoring has been recognized as a useful alternative or addition to visual inspections or local non-destructive testing performed manually. It is, in particular, suitable for mechanical and aeronautical structures as well as on civil structures, including cultural heritage sites. The main challenge is to provide a robust damage diagnosis from the recorded vibration measurements, for which statistical signal processing methods are required. In this chapter, a damage detection method is presented that compares vibration measurements from the current system to a reference state in a hypothesis test, where data9 related uncertainties are taken into account. The computation of the test statistic on new measurements is straightforward and does not require a separate modal identification. The performance of the method is firstly shown on a steel frame structure in a laboratory experiment. Secondly, the application on real measurements on S101 Bridge is shown during a progressive damage test, where damage was successfully detected for different damage scenarios. KW - Structural health monitoring KW - Subspace methods KW - Damage detection KW - Statistical tests KW - Vibrations PY - 2018 SN - 978-3-319-68645-5 U6 - https://doi.org/10.1007/978-3-319-68646-2 SP - 307 EP - 326 PB - Springer International Publishing CY - Cham ET - 1. AN - OPUS4-45127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Hille, Falk ED - Powers, N. ED - Frangopol, D. T1 - A study on diverse strategies for discriminating environmental from damage based variations in monitoring data N2 - Right from the beginning of applying SHM to bridge structures it was obvious that environmental based perturbations on the measurement significantly influence the ability to identify structural damage. Strategies are needed to classify such effects and consider them appropriately in SHM. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge taking into account environmental as well as damage based changes of stiffness values. With the back-ground of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of procedures, separating environmental from damage caused changes in SHM measures. The contribution describes both general strategies and points out their Advantages and drawbacks. As basis, a review on relevant methods was conducted. The aim of the study is to classify approaches for separating damage describing information from environmental based perturbations in dependency of the SHM objective. And such, it is intended to describe a best practice in designing concepts for Monitoring infrastructure, naturally effected by environmental influences. T2 - IABMAS CY - Melbourne, Australia DA - 09.07.2018 KW - SHM KW - Environmental changes KW - temperature PY - 2018 SN - 978-1-138-73045-8 SP - 1557 EP - 1564 PB - CRC Press AN - OPUS4-46059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Strukturschwingungen und Schwingungsminderung - Bauwerksmodelle, Messungen vor Ort und auf dem Versuchsgelände der BAM T1 - Structural Vibrations and Vibration Reduction Building Models, On-site Measurements and Test Site of the BAM N2 - Die Grundidee einer Schwingungsminderung ist es eine tiefe Eigenfrequenz der Struktur zu erreichen, so dass höhere Frequenzen abgemindert werden. Das gilt für die Minderung an der Quelle, zum Beispiel einem Eisenbahngleis, und für die Minderung am Empfänger, dem Gebäude. Die Eigenfrequenz ermittelt man aus dem Verhältnis der Auflagersteifigkeit und der Masse. Wie ist die Masse bei einem Gebäude zu wählen? Und wie ist die Untergrundsteifigkeit zu berücksichtigen? Als Referenzsituation ohne Minderungsmaßnahme? Der Beitrag bringt Rechenergebnisse zu abgefederten Gebäuden mit einfachen und komplexen (FE-) Modellen, Mess- und Rechenergebnisse zur Schwingungsübertragung von unabgefederten Gebäuden. Es wird der Einfluss der Abstimmfrequenz, der Bodensteifigkeit und der „starren“ Gebäudemasse untersucht. Die komplexen Gebäudemodelle erlauben, neben der Berechnung einer elastischen Gebäudelagerung, auch die Variation von Gebäudeparametern zur Reduktion der Deckenschwingungen. Den Ergebnissen bei der Erschütterungs-übertragung in Gebäude werden zwei ähnliche Beispiele zur elastischen Maschinenlagerung und zur elastischen Gleislagerung gegenübergestellt. T2 - 6. VDI Fachtagung Baudynamik CY - Würzburg, Germany DA - 17.04.2018 KW - Rechenmodelle KW - Elastische Gebäudelagerung PY - 2018 SN - 978-3-18-092321-5 SN - 0083-5560 VL - 2321 SP - 421 EP - 434 PB - VDI-Verlag CY - Düsseldorf AN - OPUS4-45471 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -