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Abstract: New method for experimental safety evaluation of short span bridges using the example of 14 bridges in Hannover, Germany A request on safety evaluation of culverts and short span bridges in the urban woods Eilenriede in Hannover motivated to develop and field test a new economical approach for load testing. Demolition and renewal should be avoided. A concept was worked out, how load testing could be conducted cost‐efficient with little risk of failure using mobile crane and monitoring system. This paper describes preconditions, developed procedures and summarizes our experience gained in testing successfully 13 reinforced concrete structures and one masonry arch culvert. [ABSTRACT FROM AUTHOR]

Abstract: Monitoring‐based performance analysis of tuned mass dampers in tower structures Slender structures, such as towers and masts, frequently exhibit unfavourable responses when subjected to dynamic loads, characterized by the non‐negligible contribution of higher modes of vibration as well as resonant phenomena between the loads and the structure. To mitigate such responses, tuned mass dampers (TMDs) have been employed in several slender structures. A TMD is a structural sub‐system fixed to a structure and “tuned” to counteract a response frequency, which is anticipated to induce large oscillations to the structure, through its out‐of‐phase response. The design of tuned mass dampers is based on modelling assumptions and on sparse observations of the dynamic behaviour of structures, which changes due to structural ageing, thus rendering the regular performance assessment of TMDs is essential. In this paper, a methodology for assessing TMD performance using structural health monitoring (SHM) data is presented. Specifically, the TMD functionality is assessed upon obtaining the phase shift between the TMD response and the response of the structure, which, according to TMD theory, indicates favourable dampening effect when assuming values close to 90°. The proposed methodology is validated via a case study of a telecommunication tower equipped with a TMD and an SHM system, showcasing the ability of the methodology to assess TMD performance. [ABSTRACT FROM AUTHOR]

Abstract: Brenner Base Tunnel: largest contract in the Austrian project area awarded / Brenner Basistunnel: Größtes Baulos auf österreichischem Projektgebiet vergeben With world record speed to the 10,000 metre mark / Mit Weltrekordtempo zur 10.000‐Meter‐Marke Multi‐mode TBM modernises Czech infrastructure / Multi‐Mode‐TVM modernisiert tschechische Infrastruktur Gemeinschaftskraftwerk Inn: Power house soon complete, challenging tunnelling works / Gemeinschaftskraftwerk Inn: Krafthaus vor Fertigstellung, herausfordernde Vortriebsarbeiten Denmark intends to bring forward work on the Danish side of the Fehmarn Belt / Dänemark will Arbeiten auf dänischer Seite des Fehmarnbelts vorziehen Breakthrough at the Untersammelsdorf Tunnel / Durchschlag beim Tunnel Untersammelsdorf CERN awards construction contract for extension project / CERN vergibt Bauauftrag für Erweiterungsprojekt DSI Underground Australia acquires Fero Group / DSI Underground Australia übernimmt Fero Gruppe Call for papers – Themes for the next issues of Geomechanics and Tunnelling / Themen für die nächsten Ausgaben der „Geomechanics and Tunnelling” [ABSTRACT FROM AUTHOR]

Abstract: The Institute of Rock Mechanics and Tunnelling at the Graz University of Technology was founded in 1992. From the beginning, the primary focus of research and development was on Alpine tunnelling and slope stability issues, considering geological conditions and their impact on construction. The aim was to improve the current practice, as well as to reduce uncertainties. The research areas can be roughly grouped into rock mass characterization, improvement of monitoring data interpretation, ground behaviour assessment, as well as development and improvement of support elements. The research is documented in about 110 master theses and 30 doctoral theses, and approximately 350 papers. [ABSTRACT FROM AUTHOR]

Summary: In this paper the factors influencing the service life of powerful generating lamps are considered. Possibilities of accelerated testing of the devices with the purpose of saving time and resources are described. The methodology and design of the research stand for accelerated testing are presented. Results of a study of the processes of mutual diffusion of the materials of the grid mesh and antiemission coating are shown. Criteria to evaluate the lifetime of the powerful electrovacuum devices are given. [ABSTRACT FROM AUTHOR]

Abstract: According to currently valid codes, it is not possible to determine the loadbearing capacity of unreinforced infill walls considering the deformation‐based membrane effect by incorporating the exact support conditions. One reason for this is the lack of a validated calculation procedure, which in addition to the equilibrium conditions also realistically represents the compatibility conditions of these systems. In the present paper, therefore, a new non‐linear analytical calculation procedure is presented. The main focus of the analysis of walls subject to area loading is the incorporation of the support conditions and thus the consideration of the deformation‐based membrane compressive force. Through generalised formulation and a standardised notation of the determination equations, different material behaviours and various support conditions can be taken into account with few parameters. On the action side, both lighter loading like wind loads and heavier loading like explosion loads can be considered. Through the implementation of the partial factor concept, it is possible to comply with the requirements of European codes and thus ensure the applicability of the analysis model. [ABSTRACT FROM AUTHOR]

Abstract: Greening Aspang – Hygrothermal building simulation for analysis and evaluation of various scenarios related to indoor climate. In the research project Greening Aspang [1] measurements were taken from different buildings concerning summery overheating. In the present paper simulations were taken with by „WUFI plus 3.0 dynamic building simulations”. The investigations of the research project serve as a basic for the simulations. The different buildings and its sample flats are explained in detail. The data of the simulation is validated by the measurements and extended to the entire building. The hydrothermal comfort inside the buildings has been investigated and evaluated. It turned out that none of the investigated objects, neither flats nor whole buildings, could satisfy the ÖNORM B 8110‐3 [2]. A comparison between the values of measurements and simulations shows that the simulations are very close to the measured reality. The main difference between this values is, that the measurement values vary in a larger area than the values of the simulation. By means of a variant study the effects of different methods structural measures on the hydrothermal indoor climate during a heatwave is investigated. The different structural measures are exterior shading, airing during the night, change of the colour of the façade, façadegreening and loggiagreening. Each of this structural measures reduce the summery overheating. The most effective one is exterior shading, but the more measures are combined, the better it is. A combination of all leads to the best results. [ABSTRACT FROM AUTHOR]

Abstract: In Japan, the new steel‐glass architecture of railway stations observes usually not only the typical canons of aesthetics but often also – increasingly – the local habits, traditions and social features. Moreover, such architecture is understood to respect well the natural and built environment – forming friendly compositions, which respond fairly to the needs of contemporary Japanese people. Thus, that architecture becomes certain steel‐glass art of structures. In this paper, on the basis of several practical examples, such special steel‐glass art will be presented. [ABSTRACT FROM AUTHOR]

Abstract: Modern railway bridges as thick‐plate trough bridges – Optimization of fatigue design and life‐cycle analyses. Innovative improved design solutions of bridge constructions increasingly aim at maintenance reduced structures where the utilization and surrounding traffic routes are affected only in minor extent by rehabilitation and maintenance works. As part of the FOSTA‐AiF‐research project „Holistic Assessment of steel‐ and composite railway bridges according to criteria of sustainability” (P978) specific investigations were carried out in order to optimize different railway bridge types by improving single structural details and construction variants types. To assess the benefits of these optimized constructions within the life‐cycle of the bridge, the conventional and improved constructions were compared with each other by applying sustainability analyses. This paper deals with the evaluation of the trough bridges with thick track plates which was especially developed for rail traffic constructions and which is also known as thick‐plate trough bridges. It focusses on questions related to the fatigue design, uses large scale tests for verifications and provides recommendations for the construction and design. [ABSTRACT FROM AUTHOR]

Abstract: Modern heavy plate solutions for bridge constructions for sustainable, efficient constructions. In many European countries infrastructure – road as well as railway infrastructure – needs intensive investments to follow the growing demands of mobility and goods traffic. Steel or steel composite bridges offer in this context viable and very sustainable solutions. Due to its unlimited recyclability steel can in general be seen as the ideal material for such sustainable constructions, but especially when designers or fabricators consistently exploit the potentials nowadays available thanks to smart product developments during steel production very cost‐efficient and remarkable constructions are realizable . It therefore pays off to select modern and innovative grades and high‐quality steels, like longitudinally profiled plates or higher strength thermomechanically rolled or quenched and tempered steels, as early as the planning and design phase. Modern innovations in steel permit not only highly efficient, cost‐optimized fabrication but also more slender and architectural aesthetics. This paper will highlight some of these possibilities in heavy plate production for bridge building. [ABSTRACT FROM AUTHOR]

Abstract: Applying the theory of structural state of stress, this paper investigates the behaviour characteristics of concrete‐filled stainless steel tubular (CFSST) short columns during their experimental working process. First, the sum of the generalized strain energy density (GSED) values (Eij) of the short column at every load value (Fj) is normalized as Ej,norm to describe the structural state of stress. Then, the state of stress jump is identified by applying the Mann‐Kendall (M‐K) criterion to the Ej,norm‐Fj curve creatively, following the rule of quantitative change to qualitative change. The investigation reveals the general state of stress mutation characteristics of short columns at specific individual loads, leading to an update of the failure load. Furthermore, it is verified that the simulative working behaviour of short columns can also reflect the state of stress characteristics revealed through the investigation into the experimental data. Hence, we formulate the relationship between the failure loads of CFSST short columns using the simulative data, and then validate it through both experimental and simulative data. In total, this study explores a new way to reveal some unseen working characteristics of structures; hopefully, it will initiate similar research on various structures, and the results achieved will lead to more rational design codes. [ABSTRACT FROM AUTHOR]

Abstract: Calculation of the deflection of reinforced concrete members – general procedures for slabs and beams This paper introduces the fundamental procedures to calculate the deflection in the cracked state taking into account creep and shrinkage. A range of different methods with various degrees of accuracy is presented for beams and one‐way slabs, based on the guidelines of EC2. For simple systems these methods can also be used for hand calculations, permitting a high degree of control over the procedure. Subsequently, the usually rather complex calculation of deflections caused by the shrinkage of the concrete is considered in more detail. For a selection of systems, diagrams containing coefficients for a more efficient estimation of shrinkage deflections can be derived. Furthermore, the cracked state deflection of concrete slabs is addressed more closely. It can be calculated with the help of suitable finite element programs or using simplified manual procedures. The basic principles can be transferred from the previously considered beam structures. However, other influence factors have to be addressed, such as the procedure to reduce the flexural stiffness and the redistribution of the internal forces caused by cracking. [ABSTRACT FROM AUTHOR]

Abstract: Fatigue strength of RC beams without transverse reinforcement under cyclic loads The shear design of RC members without transverse reinforcement (e.g. slabs, bridge decks, footings of wind energy plants) for fatigue loads is based on empirical approaches, which had been rarely validated by experiments. This paper presents theoretical, experimental and numerical studies, which aim to give a better understanding of the load transfer in RC members without web reinforcement under static as well as cyclic loads. Furthermore, the approach of Eurocode 2 will be examined. [ABSTRACT FROM AUTHOR]

Abstract: Rib shear connectors with concrete break out failure subjected to tension or compressive loads – Part 1: Finite Element Analysis The shear connectors in steel‐concrete composite structures have to provide sufficient resistance against stresses acting orthogonally to the shear connection leading either to uplift of the concrete slab or mutual penetration of the steel girder and the concrete. While the anchoring behavior of headed studs has been extensively researched in the past, investigations in the load bearing behavior of composite dowels subjected to tension and compressive loads are missing, to date. Therefore, the present paper describes finite element investigations in the load bearing behavior of composite dowels exposed to loads acting orthogonally to the shear connection. The FE‐model, validated against tests from literature, is used to investigate the transfer of stresses between steel dowel and concrete and to clarify the influence of different parameters, like the effect of transversal reinforcement in the concrete and the size effect of the anchorage depth. In the second part, the FE‐results are used to derive engineering models and design approaches for composite dowels subjected to tension or compression. [ABSTRACT FROM AUTHOR]

Abstract: Large‐size HV‐bolt sets in ring‐flange connections are crucial structural members of wind turbine support structures, which are subjected to strong static as well as cyclic loads with considerable numbers of load cycles. Additionally to direct experimental investigations on the structural components themselves, analytical and numerical assessment methods of the bolts performance inside ring‐flanges are valuable engineering tools to gain knowledge about the structural behaviour and to support the development of appropriate design solutions. In this paper, probabilistic fatigue assessment, using Monte Carlo Simulation technique, is utilized to compute the failure probability and to investigate the influence of the scattering parameters on the fatigue performance of HV‐bolt sets in ring‐flange connections. Subsequently, an analytical fatigue calculation approach for large‐size bolts, based on the local strain‐life concept, is introduced. Results from two different methods for determination of required base material properties are compared. The calculations are validated on fatigue tests on HV‐bolt sets and results are discussed with regard to the evaluation of local loading conditions, damage assessment parameters and sensitivity to base material input. [ABSTRACT FROM AUTHOR]

Abstract: Investigations on the load bearing behavior of composite dowels positioned close to the free concrete surface. Composite dowels are an economic alternative to headed studs with various advantages. Modern concrete slabs are dimensioned increasingly thinner and often include several additional functions, for example air conditioning or thermal activation of concrete surfaces. For those applications composite dowels can be positioned horizontally in the concrete slab. Existing investigations on composite dowels describe different failure modes of composite structures such as splitting of the concrete, local compression of the concrete, pry‐out of a concrete cone or plasticizing of the steel teeth. At University of Kaiserslautern composite dowels with positions close to the free surface of the concrete slab were investigated experimentally by push‐out‐tests and on the basis of numerical simulations. In addition, the positive influence of a spiral reinforcement between the steel teeth was analyzed. Further primary and secondary failure mechanisms were observed for this specific position of the composite dowels. These investigations and a design approach will be presented within the paper. [ABSTRACT FROM AUTHOR]

Abstract: New applications for single‐sided nuclear magnetic resonance in building materials research Single‐sided nuclear magnetic resonance NMR is a powerful tool to evaluate structure surface properties. Relevant information can be gained non‐destructively up to a depth of 25 mm with highly precise depth resolutions. As with all non‐destructive measurement techniques, single‐sided NMR only provides indirect information. The interpretation requires experience as well as controlled laboratory measurements for correlation with material properties. In this paper, several examples for the application of single‐sided NMR for the research on construction and rehabilitation materials are reported. The applications include the non‐destructive evaluation of polymer mortars, the swelling behaviour of polymer roof membranes as well as the characterisation of mortar and concrete porosity. Limitations as well as future applications are discussed. [ABSTRACT FROM AUTHOR]

Abstract: In hard rock TBM drilling, wear issues play a crucial role in the success of a tunnelling project. Thus, excavation tools must be selected carefully and be adapted to ground conditions. Wear‐related changes in the tools that occur over the course of the tools' operating lives must also be taken into account. This paper presents five basic types of macroscopic wear for cutter rings: (1) abrasive/normal wear, (2) tapering, (3) mushrooming, (4) brittle fracture of the cutter ring (special wear type 1) and (5) blockade of the roller bearing (special wear type 2). These basic wear types lead to distinct cutter ring shapes which allow deriving some fundamental characteristics of the interacting rock types. In addition, a microscopic analysis of the surfaces and associated metallographic sections from worn cutter tools has been performed. As a result, the tribological processes under the cutter, leading to tool wear, can be better understood. In summary, the investigations may contribute to a better understanding to make it easier to choose the proper TBM disc cutter for a distinct rock type in order to minimize the risk of tool‐related downtimes. [ABSTRACT FROM AUTHOR]

Abstract: First tube of the Feuerbach Tunnel broken through / Erste Röhre des Tunnels Feuerbach durchgeschlagen Rastatt Tunnel: Works continue in the east bore / Tunnel Rastatt: Arbeiten in Oströhre gehen weiter Preparations for mechanised tunnelling in Mauls / Vorbereitungen für die maschinellen Vortriebe in Mauls Breakthrough in the Eppenberg Tunnel / Durchschlag im Eppenbergtunnel ILF gains follow‐up contract at the Brenner Base Tunnel / ILF erhält Folgeauftrag für den Brenner Basistunnel Hochtief and Vinci to design and build Metro line in Copenhagen / Hochtief und Vinci planen und bauen Metrolinie in Kopenhagen Rail tunnel for Erding ring closure at Munich airport / Bahntunnel für Erdinger Ringschluss am Flughafen München Asfinag invests 1.1 billion Euros / Asfinag investiert 1,1 Milliarden Euro Risk analysis for the ”train into the clouds“ in Argentina / Risikoanalyse für Argentiniens „Zug in die Wolken” DSI takes over specialist for robotic maintenance / DSI übernimmt Spezialist für Roboter gestützte Instandhaltung Drill and blast excavation of the main tubes of the Filder Tunnel completed / Sprengvortrieb in den Hauptröhren des Fildertunnels beendet Call for papers – Themes for the next issues of Geomechanics and Tunnelling / Themen für die nächsten Ausgaben der „Geomechanics and Tunnelling” [ABSTRACT FROM AUTHOR]

Abstract: For underground construction projects in the United States and Canada it is standard procedure to use a Geotechnical Baseline Report (GBR) to contractually define subsoil conditions. The GBR sets baselines based on which tunneling contractors develop bids and plan the works. Baseline values for soil abrasiveness are a focus especially where drives with pressurized‐face Tunnel Boring Machines (TBM) beneath the groundwater table and in unstable face conditions require changing the cutterhead tools under hyperbaric conditions or in pre‐constructed safe havens. Several laboratory procedures exist that can be used for providing soil abrasiveness baselines in the context of the GBR. However, none of them cover all the soil characteristics that are relevant in causing tool wear. Also, other factors need to be considered for wear rate prediction. Analyzing the performance of previous TBM drives is a proven way to gain insight into the wear system behavior. This paper presents correlation analyses of geotechnical conditions, TBM operational data, and tool wear measurements from several TBM drives in the metropolitan areas of Seattle and Vancouver, B.C. These drives with earth pressure balance and slurry TBMs include various tool types and were conducted in glacial and interglacial deposits that are considered highly abrasive. [ABSTRACT FROM AUTHOR]

Abstract: Deflection limitation of reinforced masonry building elements under bending is undertaken according in DIN EN 1996‐1‐1:2013‐02, Section 5.5.2.6, Table 5.2 [N 4], by limiting the span l ef or the ratio of lef to the effective depth d, for example lef/d ≤ 20 for simply supported beams. A further requirement in DIN EN 1996‐1‐1:2013‐02, Section 7.3, states that reinforced masonry elements should not deflect excessively under serviceability loading conditions. For reinforced masonry with dimensions, which are within the limits stated in clause 5.5.2.6 [N 4], acceptable vertical deflection of a beam can normally be assumed. In this scientific paper, the figures stated in [N 4] for the limitation of the bending slenderness l ef/d of reinforced masonry beams like masonry or prefabricated lintels are checked by calculation with the ”ζ procedure“ from reinforced concrete theory. The suitability of this procedure was first demonstrated by comparing calculated and experimentally obtained values. It was determined that maintenance of the bending slenderness ratio lef/d ≤ 20 for the tested calcium silicate masonry lintels does not always lead to deflection values w/lef ≤ 1/250. For prefabricated straight (flat arch) calcium silicate lintels and horizontal aerated concrete lintels with limit slendernesses of lef/d ≤ 15 and calcium silicate masonry lintels with lef/d ≤ 10, w/lef ≤ 1/250 was fulfilled. With regard to future requirements for the tested reinforced masonry constructions, a method is proposed for the calculation of the limit slenderness ratio lef/d, which leads to maintenance of w/lef ≤ 1/250. Furthermore, the presented ”ζ procedure“ enables reliable calculation of deflection figures at the serviceability limit state considering long‐term effects. [ABSTRACT FROM AUTHOR]

Abstract: Comparative contemplation of reference climates regarding their influence on the energetic building performance. There is a steady increase of the importance of component and building simulation as a part of a holistic building information modeling (BIM). The quality of the simulation results is highly influenced by the selected ambient climatic conditions. Currently the user is forced to use different reference climates depending on the focus of the preferred assessment. In this paper, the impact of different German reference climates on the energy consumption of a sample building is assessed. Therefor the steady state heating degree days as well as the transient heating load of the building are compared using different ambient reference climates. Finally, the results generated with the reference datasets are set into relation to the naturally fluctuations of the local climate. [ABSTRACT FROM AUTHOR]

Abstract: Equivalent initial imperfections for applying the partial internal forces method for flexural buckling about the weak axis. This paper compares design approaches for equivalent initial imperfections of steel members with hot‐rolled double symmetric I‐/H‐profiles subjected to buckling about the weak axis. In addition to the normative rules applied in Germany and Europe, design approaches for imperfections are also taken into account, which are currently discussed as part of the further development of Eurocode 3. A proposal using the partial internal forces method allows a consistent design for steel members taking into account the cross‐sectional failure as well as the flexural buckling about the strong and weak axis. The proposal leads to design results that agree well with the results of numerical simulations. [ABSTRACT FROM AUTHOR]

Abstract: Dedicated to Prof. Dr.‐Ing. habil. Joachim Lindner on the occasion of his 80th birthday This paper reports the latest developments concerning the application of Generalised Beam Theory (GBT) to thin‐walled members with deformable cross‐section and whose undeformed axis is a circular arc, with no pre‐twist. Initially, the fundamental equations and relations are presented, leading to the first‐order equilibrium equations and associated boundary conditions, which can be written in terms of GBT modal matrices or stress resultants. Then, the procedure to obtain the cross‐section deformation modes is explained. Arbitrary (open, closed or ”mixed“) flat‐walled cross‐sections are covered, even though the kinematic constraints employed to subdivide the modes are much more complex than for prismatic members – in particular, the mode shapes become dependent on the curvature of the beam axis. Using a displacement‐based GBT finite element, a set of illustrative examples is presented, involving complex local‐distortional‐global deformation. These examples show that very accurate results are obtained with the proposed GBT formulation and that the modal solution provides in‐depth insight into the structural behaviour of naturally curved members. [ABSTRACT FROM AUTHOR]

Abstract: Introduction of the Direct Strength Method into the design of cold formed steel members according to EN 1993‐1‐3. Cold formed steel members have a varied area of applications in steel lightweight constructions but are subject to local and global instabilities due to compressive and bending stress. The design method of the European Standard EN 1993‐1‐3 is based on the Method of Effective Widths covering local and distortional buckling. Unfortunately, an EN 1993‐1‐3 design is time‐consuming and prone to errors, furthermore the results are often conservative. This paper is going to introduce a new, practical design method for cold‐formed steel sections that combines the established European regulations of global instabilities with the Direct Strength Method (DSM) described in the North American standard AISI Standard 100 regarding local stability analysis. Based on comparative studies of mono‐symmetric cross‐sections it is possible to demonstrate that this new method offers a great potential of improving the design of cold‐formed sections, additionally improves the economic efficiency of lightweight steel sections. More theoretical and experimental investigations are needed, deeper leading questions are to answer, until this method is able to supplement the European standard. [ABSTRACT FROM AUTHOR]

Abstract: Geotechnical rich due to loss of stability. In this paper the geotechnical risk as expected value of sizes of geotechnical events within an operation region and time is specified. Causative losses of stability are related with domino‐like chain reactions and losses of control which as yet cannot be calculated. Their physical extent is given by the released energy. The bigger this is and the more something or someone is exposed to a chain reaction, the higher is the damage. Due the “wild” randomness the number of chain reactions depends on the energy which is released at least by a power‐law. The exponent of it is nearly –1 as the reaction of geo‐matter is nearly rate‐independent. The power‐law has physically justified lower and upper cut‐offs. Thus the geotechnical risk is the product the lower damage cut‐off and the logarithm of the ratio of upper and lower cut‐offs. Expected values of cut‐offs have to be determined for scenarios by means of ground data, technical and other actions. Thus the risk can be calculated objectively, insurance fees can be estimated and total expenses from feasibility study to use can be reduced. [ABSTRACT FROM AUTHOR]

Abstract: Pile driving of open‐ended steel piles in offshore wind industry – comparison of prognosis and measurements. Today popular foundation methods of offshore wind turbines (Jackets, Tripods or Monopiles) are mainly realised with steel pipe piles. Against the background of cost effectiveness, the selection of a driving system as well as design fatigue calculations it is of importance to run driveability analysis prior to the installation process. Results and criteria for that are amongst others (e.g. propagation of underwater sound, not discussed here) blow count and duration of a driving process as well as the soil resistance at the moment of driving (with or without driving stops) being the so‐called static resistance to driving (SRD) and compressive and tensile stresses within the pile. At real pile driving usually dynamic pile tests are performed in order to record real blow counts und stresses in the pile and furthermore, to verify pile capacity. In the present paper theoretical driveability analyses and thus SRD models will be compared with results of dynamic pile tests in certain offshore wind farms in the North and Baltic Seas in order to check their applicability based on sand or chalk dominated soils. [ABSTRACT FROM AUTHOR]

Abstract: Behaviour of sand under cyclic loading with direction change in simple shear test. In the present paper the results of the experimental and numerical investigations of the deformation behavior of sand under cyclic loading with polarization changes are presented. In the case of a polarization change, the accumulated strain rate rises abruptly. With the focus on this phenomenon, an extensive test program has been carried out in the simple shear device with changeable shear direction. Based on these results a new approach for describing the polarization change in the explicit accumulation model is formulated. [ABSTRACT FROM AUTHOR]

Abstract: Trough girders are widely accepted in engineering on account of lowing construction depth and protection against traffic noise pollution, but most of them are used for simple‐supported girder bridges with a span of generally less than 30 m. On the railway line of Nanjing–Qidong in China a new railway bridge will be built which has a span of over 64 m but a construction depth of less than 2.4 m on which Shanghai–Nantong railway line is also passed, so the type of concrete‐filled steel tube tied‐arch bridge with trough girder was chosen. For such a new structure hardly used in engineering, there are no research results yet available about mechanical properties of the structure. This paper therefore makes for the bridge an experimental model of 1:4 geometric scale in order to test mechanical properties under operation load, cracking load, and ultimate load such as cracking diagram, load‐carrying capacity, stress distribution, and failure mechanism. According to the experimental results, when the model is subjected to longitudinal bending moment, the failure mode is similar to that of pure bending of a girder, and when the model is subjected to transverse bending moment failure mode behaves like the flexural failure mode of the traditional reinforced concrete structure. A non‐linear element analysis is also made on the model with the results in good agreement with that of the experiment. The same modeling method is applied to the finite element analysis of the real bridge, considering various load in design. In the analysis, it is finally verified that this new type of bridge meets specification requirements in strength, rigidity, and resistance to cracking. [ABSTRACT FROM AUTHOR]

Abstract: Brief for building design for waterproof concrete structures Waterproof concrete structures are used in waterproof concrete tanks, waterproof roofs and floors. These structures have been built successfully for more than four decades in the construction of buildings, industrial facilities etc. Beyond the design and construction principles of the code of practice this paper gives additional information about how to regard the client's expectations to his building. The brief for building design or identification of needs is a recommended tool that is appropriate for waterproof concrete construction to systematically capture the needs of the client and to document them in a design brief. [ABSTRACT FROM AUTHOR]

Abstract: Design of watertight concrete structures For structures in direct contact with water, the construction of watertight concrete structures has over the past decades been established as a robust, efficient and economical alternative to constructions with an external waterproofing. Design and execution of watertight concrete structures in Germany is regulated by the DAfStb guideline on watertight concrete structures (WU‐Richtlinie). The new version of the WU‐Richtlinie will be published in 2017. This paper presents the fundamentals of the design of watertight concrete structures according to the WU‐Richtlinie. [ABSTRACT FROM AUTHOR]

Abstract: Waterproof concrete constructions – recommendations for the cooperation of client, planner, special planner and contractor For a successful implementation of waterproof concrete constructions, a particularly high planning and execution quality is essential and the monitoring of the execution is required. The present paper provides advice and assistance to builders, designers and contractors for the design and execution of waterproof concrete constructions. [ABSTRACT FROM AUTHOR]

Abstract: Planning and structural design of water‐tight concrete constructions – basic design principles and their structural realization In water‐tight concrete constructions, the reinforced concrete structure in combination with planned joint sealings on the one hand and with subsequent crack injections on the other hand is also securing a defined sealing function against water exposure. The utilization demands on water‐tight constructions have been raised significantly over the past years leading in the same degree to higher demands on quality of planning and building processes for these constructions. Present water‐tight constructions are high‐performance structures whose demands on the planning process exceed the common knowledge in architectural and structural design by far. There is general planned about the quality‐regulating, constructive aspects (reduction of constraint stresses, concrete technology and post‐curing) for these structures. But regarding the analytical calculation models for constraint forces, a huge scatter in assumed exposures and resistance as well as a fuzziness of existing models have to be noticed leading to non‐reproductive and blurred calculative design results. This paper is focussing on exposures and resistances as well as on different calculation models leading to practical recommandations for the structural design which is only insinuated in the basic rules for water‐tight constructions. [ABSTRACT FROM AUTHOR]

Abstract: Material characteristics of a historical reinforced concrete bridge – A report about material investigations on existing structures, dedicated to Jürgen Schnell's 65th birthday The determination and characterization of material properties of existing structures is a current focus of research by Prof. Schnell, to whom the article is dedicated. The recent published books of the DAfStb (publication series nr. 616 and 619) provide the expedients for the practicing engineer to determine material strength to evaluate existing structures. Within a historical project on the former civil engineer and professor of the TH Dresden Willy Gehler, the properly oldest reinforced Hennebique concrete bridge of middle Germany was found. The bridge was demolished in 2016 because of a limited flow rate. At least this offers the opportunity to obtain sample material. The investigations on the material behavior were described in the paper as well as a discussion on the difficulty for its determination of values for recalculation. [ABSTRACT FROM AUTHOR]

Abstract: Load‐bearing capacity of unreinforced concrete compression members under biaxially eccentric loading Compression members, such as columns or walls, have to carry vertical loads primarily. Due to the rotation of the adjacent components, they are also subjected to bending moments. If the compression member is, in addition to the bending moment about the weak axis, also loaded by horizontal bracing forces in direction of the strong axis, bending moments about both axes (biaxial bending) occur. This paper deals with the load‐bearing capacity of slender, unreinforced and biaxially eccentrically loaded compression members made of concrete. Existing theoretical methods for determining the load‐bearing capacity of centrically and uniaxially eccentrically loaded compression members are shown as well as the corresponding normative regulations. On this basis, two practice‐oriented proposals for determining the load‐bearing capacity of biaxially eccentrically loaded unreinforced concrete compression members are presented. The proposals can easily be adopted into the standard and thus, the existing restricting limits of application can be neglected. [ABSTRACT FROM AUTHOR]

Abstract: Non‐destructive assessment of concrete using the pulse‐echo method – possibilities and limits For an effective assessment of the condition of concrete structures non‐destructive methods are required. The ultrasonic pulse velocity technology offers a suitable non‐destructive on‐site testing method. The on‐site applications of the pulse‐echo method and the interpretation of the measured data require essential practical engineering expertise. To support and improve the practical experience it is necessary to apply the pulse‐echo method under well‐defined laboratory conditions. Such conditions allow verifying the complex measurement results. Consequently, the user can practice the correct handling and analysis of the pulse‐echo method. This paper shows the planning and production of special concrete specimens. In these concrete elements different defects and cladding tubes, which vary in geometry and in dimension, were integrated. Furthermore, using these specimens the effective application of the pulse‐echo method as well as the analysis and reliable interpretation of the achieved data can be realised. Recommendations concerning the target‐oriented application of the pulse‐echo method will be given. [ABSTRACT FROM AUTHOR]

Abstract: External thermal insulation composite systems (ETICS) improve the thermal insulation of the building envelope, and thus contribute substantially to saving heating energy. However, they also considerably affect the acoustic characteristics of exterior walls. Depending on the design of the ETICS, this can lead to either an improved or an inferior acoustic insulation. For this reason, already about fifteen years ago, planning tools were developed which allow to predict reliably the sound insulation of walls with ETICS. The applied calculation models are still used today. As the structure of exterior walls has changed significantly since then due to the more stringent requirements for thermal insulation, additional investigations were needed to adapt the existing models to the current construction methods. This paper presents the results of the research project carried out on this topic and provides a summarizing overview of the current state of knowledge on the sound insulation of walls with ETICS. It also discusses the acoustic impact of ETICS within the context of the overall structural situation, as well as the importance of spectrum adaptation terms for constructional noise protection. An overview of all formulas required for a prediction of the sound insulation facilitates the practical application of the developed calculation methods. [ABSTRACT FROM AUTHOR]

Abstract: Limitations on the use of partial shear connection in composite beams with single flange steel beams and composite dowels – Part 2: Analysis of the load bearing and deformation behaviour and modes for the minimum degree of partial shear connection. For composite beams with single flange steel beams and composite dowel connectors, the limitations to the use of partial shear connection have not yet been clarified. In this paper (continuation of [1]) the bearing and deformation behavior is analyzed using experimentally verified FE models. For this purpose, a comprehensive parametric study is performed, in which, in addition to the degree of shear connection and different cross‐sectional types, different parameters of the composite beam are varied which do not enter into the analytical calculation of the plastic bending moment capacity. These are, on the one hand, properties which depend on the static system, such as the loading situation (single load or uniformly distributed load) and the span, on the other hand, the slip deformation behavior of the connectors is varied by establishing different ductility characteristics for pry‐out and steel failure of composite dowels. Based on the simulation results, equations are derived for the minimum degree of partial shear connection for beams with single flange steel sections and composite dowel connectors including all required limitations of use for plastic design. The own models are compared to regulations given in a technical approval for composite dowels. The models may also be adopted for composite beams with steel T‐sections and horizontally lying shear studs. [ABSTRACT FROM AUTHOR]

Abstract: Failure of a steel pallet rack in Athens. Pallet racking systems have peculiar characteristics which differ from usual steel structures that make them sensitive to stability failure modes. In the present paper a rack failure is presented where the rack has failed due to lateral torsional and distortional buckling of its most stressed uprights. The structural behavior was studied by a combination of experimental and numerical/analytical methods. The investigations included test loading, bending tests on pallet beams, compression tests on stub column and bending tests on beam end connectors. Subsequently, a global geometrical non‐linear analysis is performed on the 3‐D system. Its results indicate by comparison with the pictures of the actual structure that the collapse mode is correctly detected. Conclusions are drawn that recommend the performance of static and dynamic analyses on an obligatory basis. [ABSTRACT FROM AUTHOR]

Abstract: 50th anniversary of the Bonn‐Nord (Friedrich‐Ebert) Bridge across river Rhine. This bridge, opened to traffic on June 28, 1967, was the world's first cable‐stayed bridge with a central multicable system (80 locked coil ropes) and has a main span of 280 m. The 36.3 m wide bridge deck consists of a central steel box girder and wide cantilevers, the 49.4 m high towers are also from steel. The side spans were erected on the final and auxiliary piers and the main span by free cantilevering. The paper deals with the design, shop fabrication and erection of the bridge, a recent structural health monitoring and the results of calculations according to the actual Eurocodes. Although the bridge does not meet some of the actual requirements, no major structural defects have been detected. So, the life time of the bridge may not be determined by the structural but by the traffic capacity which may require a wider bridge in about 2040. [ABSTRACT FROM AUTHOR]

Methods to reduce the partial safety factor concerning dead loads of existing bridges The recalculation guideline for existing concrete bridges allows to reduce the partial safety factor for dead loads from γG = 1.35 to 1.20 which matches a conservatively estimated model uncertainty factor. Pre-requisite is that geometry, concrete's specific weight and reinforcement ratio are known from sufficient und representative measurements on-site. In recalculation according to the guideline, the dead load variation driven by these three factors is considered directly by the load distribution. However, no details on required accuracies of the measurements are specified at all. This paper shows how tailor-made partial safety factors can be derived from on-site measurements and supplemented with empirical data from literature. For existing bridges, it seems appropriate to measure the geometry and to estimate the variation of concrete's specific weight while the reinforcement ratio is taken from construction drawings. For application a reference bridge is jointly measured in cooperation with the land surveying office of the state capital city Düsseldorf. 3D laser scans and multicopter over-flights deliver a digital model. In general, the presented approach is relevant for recalculation, modification and deconstruction matters of existing bridges. [ABSTRACT FROM AUTHOR]

Fair-faced concrete designs undergoing a revival since the beginning of the new century until now. In the building practice there are over and over again unwanted effects on a fair-faced concrete surface, despite the continuous further development. The "system fair-faced concrete" with varied influences from formwork, concrete, concrete processing and aftertreatment including the weather conditions is an extremely demanding one. The control of this system presents a particular art. This paper will show the possibilities of the concrete technology and concrete processing for a nice, individual and predictable fair-faced concrete surface. [ABSTRACT FROM AUTHOR]

The present contribution offers a first philological description of Durs Grünbein's 'Vorlass' at the German Literature Archive in Marbach, and examines in particular the palimpsest-like modus operandi of the poet, which aims at documenting every step in the genesis of his texts. Moving from the analysis of different papers from the time before and after Grünbein's literary consecration, the article poses the question of the author's consciousness about his future literary estate ('Nachlassbewusstsein'). Special attention is thereby given to the self-archiving strategies he deploys as well as to the interpretational hints he seems to disseminate in his documents for later philology. Furthermore, the fact that as yet unpublished texts can be found in the 'Vorlässe' of contemporary writers encourages philologists to conceive of the literary estate more widely as a place where not only the past and posthumous, but also the current and anthumous dwell. [ABSTRACT FROM AUTHOR]

Simulation programs like the Finite Element Method belong to the set of standard tools in product development. These systems are used to describe scientific problems using mathematical means and present the solutions for those problems in a graphical way. They also support the development process of a product significantly. Subject matter decisions however, are made by the calculation engineer. To do that, she needs sufficient theoretical, application specific knowledge and thus knowledge about potential sources of errors. As errors in the analysis cannot be ruled out even until the very end of the project, certain subject matter risks persist. Consistent process and quality management can help mitigating those risks or even avoid them completely. Liability risks are strongly related to subject matter risks. For those, we can distinguish between contractual and non-contractual liabilities. Product liability claims belong to the latter, too. Fundamentally, the risk to be accountable for a product defect is the greater, the more responsibility the calculation engineer has within the company. This paper is supposed to give an overview about the civil law liability risks of calculation engineers. This means, it especially targets companies and engineers that provide calculation services to third parties or execute those services for internal product development. [ABSTRACT FROM AUTHOR]

The ultimate limit state of retaining structures with vertical loads considers in general diverse degrees of mobilization for vertical earth pressures independent from vertical displacements of the wall. The vertical component of the earth pressure on the earth-retaining site is coupled to the classical design. Shifting the design to the partial safety factor concept has shown an increasing significance of the vertical bearing capacity of earth retaining structures. In this paper, the mobilization of the vertical resistance of retaining walls is investigated with numerical methods and it can be shown that for the ultimate limit state a decoupling of the vertical resistance from horizontal stress states due to the classical design is reasonable. [ABSTRACT FROM AUTHOR]

The problem about microplastics is discussed more and more in media and in academia. In cosmetic products microplastic is used, e.g., as abrasive particles in face peelings. Sewage carries the microplastic into the environment. Here it leads to various problems. Pollutants can accumulate, and it is also mistaken with food by animals. This paper studies whether biowaxes have the physical and technical characteristics to be used as an environmentally friendly alternative instead. [ABSTRACT FROM AUTHOR]

In Deutschland werden Hochwasserschutzbauwerke i. d. R. so bemessen, dass sie einem Hochwasserereignis mit einer definierten Eintrittswahrscheinlichkeit standhalten können. Bei der Festlegung der anzusetzenden Eintrittswahrscheinlichkeit sollten die im Versagensfall zu erwartenden Schäden in dem zu schützenden Bereich berücksichtigt werden. Die erwartete Nutzungsdauer für z. B. Deiche beträgt dabei i. d. R. zwischen 50 und 100 Jahren. Die geotechnischen Nachweise sind entsprechend europäischer Regelungen und nationalen Ergänzungen für eine Referenzperiode von 50 Jahren durchzuführen. Hinweise zum Hochwasserschutz in Bau- und Revisionszeiten werden nur beispielhaft erwähnt, wie anfallende Baumaßnahmen nur in Jahreszeiten auszuführen, in denen die Wahrscheinlichkeit großer Hochwasserereignisse geringer ist. Dabei stellt sich jedoch die Frage nach einem Wiederkehrintervall, das hier angesetzt werden sollte. Letztlich geht es um die Abschätzung der Wahrscheinlichkeit, dass ein bestimmtes Ereignis an einem Standort in einem Zeitraum der Bau- und Revisionsphase eintritt. In diesem Beitrag wird exemplarisch ein Ansatz unter Anwendung der Poisson-Verteilung vorgestellt, der den Zusammenhang zwischen der Eintrittswahrscheinlichkeit von Bemessungsereignissen unter Einbeziehung der benötigten Bau- und Revisionszeiten sowie der Schutzbedürftigkeit des Hinterlands berücksichtigt. Design events for temporary construction or revision periods of flood protection measures Flood protections measures in Germany are designed in a way that they can withstand a flooding event with a defined frequency of occurrence. The evaluation of the return period of the design event should include potential damages in the hinterland or the protected area, respectively. However, flood protection structures are usually designed for an estimated operation time between 50 and 100 years. The geotechnical evidence has to be carried out in accordance with European regulations and their national supplements for a reference period of 50 years. But, the realization of the flood protection in terms of temporary construction or revision phases is only mentioned exemplarily as to perform them in seasons in which the likelihood of large floods is less. Here, the question arises about the return period to account for. Hence, the focus is on estimating the probability that a particular event occurs at a specific site during the construction or revision period. In this paper, we introduce an approach based on the Poisson distribution taking into account the relation between the frequency of occurrence of design events and the construction or revision period as well as the vulnerability of the area to be protected. [ABSTRACT FROM AUTHOR]

Die Durchgängigkeit bei Querbauwerken (z. B. Sohlrampen, Sohlstufen, Wehre, Staudämme) für die aquatische Fauna wird u. a. durch die EG-Wasserrahmenrichtlinie zur Erreichung eines guten Zustands von Gewässern zwingend gefordert. Eine Möglichkeit zur Umsetzung bildet der Einsatz von beckenartigen Fischaufstiegsanlagen in Form von Schlitzpasskonstruktionen (z. B. klassische Bauart, Rundbeckenpass u. a.). Diese sind durch mindestens eine bis zur Beckensohle durchgehende Schlitzöffnung in der Trennwand zwischen zwei aufeinanderfolgenden Becken charakterisiert. Im Beitrag werden die konstruktiven und daraus folgend die hydraulischen Charakteristika diskutiert. Der Schwerpunkt liegt dabei auf dem hydraulisch relevanten Schlitzbereich. Es werden vereinfachte und somit praktisch universell einsetzbare 1d-Formelansätze für die Bestimmung der maßgeblichen Fließgeschwindigkeiten und des Dotationsabflusses vorgeschlagen. Die Durchströmung eines Schlitzes stellt dabei eine Kombination aus Überfall und seitlichem Ausfluss aus einem Becken dar. Hydraulics of vertical slots in fish passes The passage of fish of artificial obstructions (e. g. weirs, dams) is explicitly demanded by the EU-Water Framework Directive in order to achieve good biological connectivity and therefore good conditions for the concerned water bodies. The usage of fish passes with tanks and slots (e. g. classic vertical-slot-pass, meander-type fish pass) is a possible solution. This design variant of fish ladders is characterised by at least one continuous slot in a divide wall between two neighbouring tanks. The paper offers a discussion about the design criteria and the essential hydraulic characteristics. Thereby the slot-opening sector represents the centrepiece. Simplified and universally applicable approaches for determining the significant flow velocities and discharges are proposed. It needs to be noted that the flow in a slot can be handled as the combined result of overfall and lateral outlet. [ABSTRACT FROM AUTHOR]

Hochspannungsstahlgittermaste sind Stahlbauwerke. Der Nachweis erfolgt in Deutschland seit 1903 nach verschiedenen Ausgaben der VDE 0210. Die aktuelle Ausgabe und alle Vorgängerausgaben enthalten keine Berücksichtigung der Höhe möglicher Schadensfolgen. Das bedeutet, dass für alle Maststandorte, ganz gleich ob in bebautem Gebiet oder in Gebieten ohne Personenzugang, die gleiche Versagenswahrscheinlichkeit angestrebt wird. Eine Grenze für diese überall gleich angestrebte Versagenswahrscheinlichkeit ist allerdings unbekannt, denn ein Zahlenwert für die zugelassene Versagenswahrscheinlichkeit wird in den VDE 0210-Normausgaben, wie bei anderen technischen Normen des Bauwesens auch üblich, nicht genannt. An Maststandorten mit kleinen Schadensfolgen werden somit möglicherweise mehr -Ressourcen eingesetzt als nötig, an Maststandorten mit großen Schadensfolgen fehlen diese dann eventuell. Der vorliegende Beitrag zeigt am Beispiel von Hochspannungsstahlgittermasten eine Möglichkeit, bestehende Bauwerke probabilistisch nachzuweisen und die der Gesellschaft zur Verfügung stehenden -begrenzten Ressourcen optimal einzusetzen. Probabilistic static calculation of existing high voltage steel lattice towers. High voltage steel lattice towers are steel constructions. The static calculation happens since 1903 in accordance with several editions of VDE 0210. All editions of this code including the current edition include no consideration of an amount of failure consequences. At all tower locations the same value of probability of failure is targeted. It does not matter whether the location is built-up or there is no admittance of persons. A limit for this everyplace equal targeted probability of failure is certainly unknown. A value for the tolerated probability of failure is commonly not mentioned in codes of civil engineering including the VDE 0210. At tower locations with little failure consequences more resources than necessary will set in. It is possible that these resources are missing at locations with high failure consequences. This paper tells about an optional method for probabilistic static calculation of existing constructions using the example of high voltage steel lattice towers. Subsequently the limited available resources of human society can be used optimally. [ABSTRACT FROM AUTHOR]

Die Sichtprüfung von Schweißnähten ist die einfachste und am häufigsten durchgeführte Art der Schweißnahtprüfungen. Neben laufenden Soll-Kontrollen durch das Schweißpersonal während der Fertigung ist abschließend die Sichtprüfung für alle Ausführungsklassen vollumfänglich nach EN 1990-2 durchzuführen. Dabei können direkte und indirekte Prüfmethoden angewendet werden, zu denen auch die Geometrieerfassung durch Laserscanning zu zählen ist. In diesem Beitrag wird die praktische Anwendung eines mobilen Laserscansystems für den Vergleich unterschiedlicher Schweißverfahren und Schweißlagen aufgezeigt und das Potential einer vollautomatischen Sichtprüfung erläutert. Ein solches Verfahren besitzt gegenüber einer manuellen Sichtprüfung einige Vorteile. Zum einen kann eine hoch qualitative und vor allem unabhängige Bewertung der Schweißnahtqualität sichergestellt werden. Des Weiteren können die so gewonnen Daten zu Dokumentationszwecken sowie als Inputdaten für eine Ermüdungsberechnung der entsprechenden Bauteile zum Einsatz kommen. Der letzte Punkt wird in Teil 2 dieses Beitrages thematisiert werden. Welded seam evaluation based on 3D laser scanning - Practical application of mobile laser scanning systems for surface analysis of welds - Part 1. The visual examination of welds is a simple and frequently used method for weld inspections. Besides the comparison between a target and performance state executed by the technical staff during the production process, a final visual inspection of the welds for all execution classes is demanded by EN 1990-2. According to this code, direct or indirect methods can be applied. An example for an indirect method is the scanning of the real geometry of the weld using laser scan technology. In this paper the practical use of a mobile laser scan device is shown. Different welding methods as well as different welding positions are examined and the potential of a fully automatized (visual) inspection is exemplified. Such a procedure offers important advantages compared to a manual examination. On the one hand a high quality and most important an independent examination of the weld quality can be ensured. This data can also be used for documentation purposes and as input for a component specific fatigue life calculation. This calculation is described in part 2 of this article. [ABSTRACT FROM AUTHOR]