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Translation abstract Legitimation of circular timber constructionThe sustainability principle requires that only as much wood is removed from the forest as will grow back in the same period. The annual harvest volume available for use in construction is therefore limited, also in view of the fact that other sectors of the economy are increasingly relying on the raw material. Accordingly, the aim is to maximise carbon storage as the sum of the carbon bound in the forest and the material use of wood. For the construction industry, this means maximising the longevity of building components by using wood as a resource in a circularly effective way. On the one hand, this paper presents the strategic approach to increasing the circularity of timber construction. On the other hand, the climate‐relevant proof of the necessity of circularly effective construction is provided and demonstrated using a dynamic balancing method. For this purpose, it is shown for resource consumption and global warming potential how circularly effective construction can be quantified in principle and in particular with wood. [ABSTRACT FROM AUTHOR]

A mechanically consistent approach for stability verification of timber beams in compression and bending around the strong axis, part 1 – derivations Slender timber beams in bending can be designed using different methods in view of out‐of‐plane stability. Lateral torsional buckling may be verified either using the so called equivalent member method or by means of 2nd order calculations, considering equivalent imperfections. However, at present determining the lateral torsional buckling resistance using either of these both methods, leads to different results. In this paper, the background of both verifications is investigated in deep. Moreover, as an alternative approach, a non‐linear calculation with an imperfection shape in affinity to the critical shape is presented in part 1 of this paper. If the curvature amplitude is scaled, the same results as by the equivalent member method are achieved. It is shown that plasticity effects can be considered with high precision as well. In part 2, results of experimental tests on lateral torsional buckling of glued laminated timber and laminated veneer lumber beams are presented, with nearly ideal boundary conditions and load remaining vertical through‐out the test. Based on these test first tentative values can be obtained for the imperfection compatible with the alternative lateral torsional buckling approach presented. [ABSTRACT FROM AUTHOR]

Diagonal Laminated Timber (DLT) – resource efficiency through optimized layer arrangements: determination of stiffness properties and deformation analysis This paper deals with the development of diagonal laminated timber (DLT), a composite timber product consisting of individual layers, which are rotated to each other at a certain angle to increase stiffness properties. Therefore, DLT represents an application‐optimized further development of cross laminated timber (CLT). DLT achieves improved mechanical properties with the same amount of material. [ABSTRACT FROM AUTHOR]

Methods for digital 3D assessment of the disaster situation: lessons from the 2021 flood The flood event of July 2021 caused heavy structural damage to general building stock and infrastructure in the particularly affected areas of Rhineland‐Palatinate and North Rhine‐Westphalia. In order to cope with the consequences and to prepare for future events, different research projects were initiated. The authors coordinated and interlinked these in the area of situational awareness in the form of topic‐specific workshops. The paper focuses on the collection and preparation of damage data as well as first methodological approaches to conceptually structure the disaster situation from the point of view of the various main actors and to design it efficiently in the time frame. The results are elements of a (still under preparation) tool for rapid situation assessment and support of the emergency services, the justification of measures for temporary building safety and support for reconstruction based on reliable risk scenarios and damage prognosis. Based on and after evaluation of available data and information sources, it is shown how purely technically (flights) and empirically (based on improved damage functions) the creation of situation reports can be qualified and the availability of decision‐relevant information be stored in advance. Conclusions and recommendations from the studies and workshops are summarized from the user's point of view. [ABSTRACT FROM AUTHOR]

Long‐term crack monitoring of prestressed concrete structures by means of distributed fiber‐optic strain sensing In the ceiling area of a connecting subway tunnel in Munich, Germany, fiber‐optic sensor cables were installed for continuous long‐term crack monitoring. According to the measurement concept, continuous monitoring of the total deformations as well as several reference date measurements are planned with regard to the actual crack monitoring of the prestressed concrete construction. The aim of the measurements is the fiber‐optic crack monitoring of a pre‐damaged prestressed concrete structure from the 1970s, which was refurbished in the course of the fiber‐optic installation. The structure is exposed to high traffic loads from road traffic as well as temperature impact. The prestressed concrete structure is a single span slab construction with straight and parabolic tendons. The original ceiling had an increased potential for damage on the underside of the slab (crack pattern) as well as severe damages associated with the existing prestressing steel structure. During the renovation of the prestressed concrete slab, shotcrete with supplementary reinforcement was applied to achieve an announcement behavior in case of tendon failure. The following paper reports on the first results of crack monitoring based on continuous fiber optic measurements along the embedded fiber‐optic sensing cables. The measurements are based on the technology of distributed Brillouin sensing. [ABSTRACT FROM AUTHOR]

Dynamic train‐bridge compatibility: the reference method as a new form of verification Newly developed rail vehicles must be investigated regarding dynamic bridge compatibility before they are placed in service on the rail network of DB Netz AG. In this context, the dynamic effect on bridges from passing trains (train‐bridge interaction) is evaluated based on dynamic calculation results in the ultimate limit state (ULS) and in the serviceability limit state (SLS) and compared with calculated (previously static) minimum capacities of the infrastructure (resistance). In this paper, a new form of verification is presented. It makes it possible to extend the existing static capacities of the bridges by existing dynamic capacities, which usually allow higher permissible vehicle speeds in the railway network. For this purpose, computational results and database‐supported expert knowledge (fusion) from short‐ and long‐term monitoring of existing vehicles and their impact on the infrastructure are used to declare the bridge stock for these existing vehicles as operationally verified. On this basis, an applicable dynamic capacity for new vehicles can be formulated. The procedure is exemplarily shown for the ICE 3 (existing vehicle) and the new development of the BR 408 series (ICE 3neo). [ABSTRACT FROM AUTHOR]

Rods glued into cross laminated timber – experiments, numerical simulation and load capacity prediction Timber construction is currently pushing new boundaries in terms of dimensions and architectural possibilities, as shown by the increasing number of high‐rise buildings. This is made possible by high‐performance connections, such as glued‐in rods (GiR, with rods made of steel and fibre reinforced polymers), and wood materials, such as cross‐laminated timber (CLT), which consists of several layers of boards glued flat and crosswise to each other, or glued‐laminated timber (GLT) where all layers are glued together in the same orientation. This paper highlights the current state of the art of GiR glued into CLT and gives an overview of recent experimental and numerical results. The similarities, but also the differences, between GiR glued into CLT and GLT, which result from the different orientation of the individual layers, are shown. Another focus is on the prediction of the connection load‐carrying capacity, for which only very few approaches are currently available. [ABSTRACT FROM AUTHOR]

A shear connector for direction‐independent shear force transmission in TCC slabs Currently used timber‐concrete composite (TCC) slabs carry loads only in one direction, and notches or other shear connectors are used for shear force transmission. As a result, these slabs lack the flexibility and effectiveness as a two‐way spanning, reinforced concrete flat slab. To overcome these limitations, a novel bi‐axial spanning TCC slab is being developed. The investigation of this new system is part of a research project, carried out at the University of Kaiserslautern (TUK) in collaboration with Werner Sobek Frankfurt GmbH & Co. KG (WS Frankfurt). The connection of the two cross‐sections is a key component in such systems. Therefore, developing a shear connector for direction‐independent shear force transmission is an important aspect of this project. In this paper, the results of numerical and experimental investigations of the connection system (cylindrical concrete notch) are presented and discussed. The focus is on the stiffness and load‐bearing capability as well as the structural behaviour. [ABSTRACT FROM AUTHOR]

Prognostic determination of life cycle rate of return with BIM The value retention of real estate is increasingly ensured by the inclusion of sustainability aspects in the planning. As a result, life‐cycle considerations of the future earnings situation of a property are already necessary in the project development phase. By comparing the revenues to the life cycle costs, the life cycle return (LCR), as it is called by the authors, can be determined as a prognostic parameter for assessing the profitability of an investment. In this paper, the project information available at an early stage is integrated into a digital building model to determine the LZR. Building Information Modeling (BIM) can reduce the uncertainty of the cost calculation in an early project phase by linking the digital planning status with relevant building information. Based on a digital building model, it is thus possible to determine the LZR in a way that is comprehensible and adaptable to planning variants. The breakdown of all revenues and costs relevant for the life cycle is necessary for this. Changes and additions to the building model require a continuous and rapid adjustment of the calculations to the respective planning status. This makes it possible to continuously check the initial parameters defined at the beginning of the project. [ABSTRACT FROM AUTHOR]

Transverse sliding of the 985 m long steel Lennetal bridge The Lennetal bridge is one of the major viaducts on the A45. Due to the increased traffic volume and the structural condition of the existing bridge, it was necessary to build a new bridge. In order to restrict traffic as little as possible during the construction period, the new superstructure was built for one direction of traffic in a lateral position and then moved to its final position by means of a transverse sliding. With a length of almost 1000 m, the Lennetal bridge is – in relation to the bridge length – the largest transverse sliding that has been realised in Germany so far. This paper deals with the special features of the planning and execution of the transverse sliding. [ABSTRACT FROM AUTHOR]

Simplified consideration of framing effects in masonry buildings Due to the increased requirements resulting from higher wind and earthquake loads, it is necessary to improve and optimise the calculation and design approaches for masonry structures. An important contribution to a better utilisation of the structural load‐bearing reserves is the consideration of the framing effects through the activation of the floor slabs in the calculation models, which has not been utilised in practice so far due to the complexity of the wall‐slab interaction. The paper presents a simplified approach based on the contributory slab width, which captures the essential influencing factors in parameterised tables. This provides structural engineers with a simple tool to exploit the frame load‐bearing effect in masonry design. [ABSTRACT FROM AUTHOR]

Investigation of the withdrawal capacity of thread‐optimized wood screws The withdrawal capacity is necessary for the design of screws for application in timber, so called wood screws. The withdrawal capacity is influenced by the thread geometry of the screw which interact with the wood properties. Prior investigations have not been able sufficiently determine the influence of the thread parameters on the withdrawal capacity to enable thread geometry optimization. In investigations with so‐called thread‐test‐objects with straight thread flanks, the influences of thread parameters were determined. However, the transferability of these results to wood screws is still unclear. Aim of this paper is to investigate this transferability. To do so, various thread geometries optimized for withdrawal capacity were designed. To test the transferability of the results, the withdrawal capacity of two screw variants with optimized thread geometries, a reference variant and a commercial wood screw is measured. The two optimized screw variants show significantly higher withdrawal capacities compared to the reference variant and the commercial screw variant. This demonstrates that the findings based on the thread‐test‐objects are transferable for the design of wood screws. Manufacturers can therefore use these to optimize the wood screw geometry. [ABSTRACT FROM AUTHOR]

Persönliches Nachruf auf Hans Peter Tzschucke Nachrichten Modellfabrik für Carbonbeton in Leipzig eröffnet Wettbewerbe bauma Innovationspreis 2022 Veranstaltungen Call for papers – 12. Symposium Experimentelle Untersuchungen von Baukonstruktionen (SEUB) 40. Deutscher Stahlbautag in Berlin [ABSTRACT FROM AUTHOR]

Parametrization in bridge construction for the application of artificial intelligence For the application of digital methods in the execution phase, the acquisition of exisiting structures or the construction progress with the aid of LiDAR is a suitable method to subsequently detect components as automatically as possible and e. g., to evaluate them for construction progress monitoring. Machine learning methods are suitable for component detection and are used for various classification problems. One problem is the semantic segmentation of point clouds, in which the individual points are assigned to specific component classes. To solve the segmentation with sufficient accuracy and to make predictions on real data, a large amount of training data is needed. This process is also called "Scan to BIM". In this paper, synthetic data for training a convolutionalneural network (CNN) is provided in a highly parameterized and fully automatic way. An approach for generating variations of bridge models based with the visual programming interface Dynamo in Autodesk Revit is proposed. At the beginning, guidelines for the definition of parameters are evaluated to subsequently use them in adaptive templates. Attributes are assigned to each component and grouped into a feature structure when exported to the IFC data format. This approach resulted in numerous variations of bridge models that can be used for semantic segmentation of point clouds and training of a CNN. [ABSTRACT FROM AUTHOR]

Nachrichten NEWood – ein kreislaufgerechter Baustoff Der Baugrund als digitaler Zwilling Tagungen & Veranstaltungen Brückenbautage am 10. und 11. November in Düsseldorf Veranstaltungen 4. Symposium Ingenieurbaukunst – Bauen mit und im Bestand 21. Internationale Baustofftagung – Call for Papers [ABSTRACT FROM AUTHOR]

Glued‐in rods into hardwood at low temperaturesGlued‐in rods are a connection type that has become indispensable in timber construction. Currently, two‐component epoxies and polyurethanes are used for this purpose. However, these have two major disadvantages: on the one hand, they take a relatively long time to cure completely, more than a week depending on the system, and on the other, they only cure at temperatures > 18 °C. Both disadvantages hinder the use of glued threaded rods, especially on the construction site. This paper presents investigations to evaluate accelerated curing of 2K‐epoxies and polyurethanes in timber construction. In previous investigations, the feasibility of rapid curing by induction in the area of glued‐in threaded rods in timber construction under standard climate (+23 °C, 50 % rel. LF) has been proven. This paper presents results on accelerated curing under low temperatures (+5 °C and –10 °C) and compares the results with reference specimens bonded at +23 °C. It is shown that especially 2K‐epoxides can be cured quickly even at low temperatures. However, it was also shown that fast curing has an influence on the strength of the bond. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose‐fibre lightweight concrete – a novel building material based on waste paper The present paper sets out a new method for the systematic formulation of lightweight concretes incorporating cellulose fibres. Lightweight concretes of this type are basically produced by mixing a cement paste with cellulose fibres won from waste paper. This is a combination of materials that can be expected to give rise to a whole range of positive interactions. Raising the fibre content, moreover, can additionally induce properties typical of insulating materials. Consideration is given to the suitability for this purpose of a variety of secondary fibrous materials as well as to the process of pulping them in concrete mixers. A viable procedure for characterising the various cellulose‐fibre sources and acquiring input values for the material volume calculation is elucidated. An algorithm for calculating the concrete composition required to achieve specific dry bulk densities in the hardened concrete is likewise presented. Adding fibres to the mix yields significantly altered rheological properties relative to conventional concrete. With regard to placing and compaction technologies, a division into three different basic types is proposed in this respect. A suitable method of consistency testing is introduced. The paper concludes by presenting the spectrum of properties of CFLC in both fresh and hardened states as achieved in the experimental investigations. [ABSTRACT FROM AUTHOR]

Abstract: Claim requests for general costs according to the equivalence principle for the change of quantities and for delays of VOB/B contracts Following the equivalence principle the claim requests for general costs according to § 2 Abs. 5 and 6 VOB/B and also for delays according to § 6 Abs. 6 VOB/B were already described in former papers. In the actual paper the claim request for general costs for the change of quantities according to § 2 Abs. 3 VOB/B will be explained as well as a more detailed explanation of the consequences regarding the general costs due to delays according to § 6 Abs. 6 VOB/B respectively § 642 BGB. As result a new modular method for the claim requests for general costs will be presented, which can be described as explicit, uniform, comprehensible from the economical construction point of view and also consistent with the actual VOB/B requirements. The consideration of the equivalence principle implies that the balance between the contractual performance and compensation when the construction contract is concluded remains valid also after contractual changes. This assumption is of extraordinary importance as all construction experts and parties involved accept this principle. [ABSTRACT FROM AUTHOR]

Abstract: Distributed Strain Sensing in geotechnical – a first standard for fiber optic strain measurements in geotechnical engineering The aim of this paper is to provide a recommendation for the use of Distributed Strain Sensing in geotechnical engineering. The reason for this is the increased use of this measurement method in special civil engineering. The field of distributed fiber optic sensor technology is a broad field. There are measuring methods for dynamic (time resolution in the kHz range) and non‐dynamic measurements (time resolution in the MHz range up to stationary). The measurement area dealt with in this paper refers exclusively to non‐dynamic strain measurements by means of distributed sensing. The article contains a brief description/comparison between single point measurement and distributed sensing. In addition, the previous field of application for Distributed Strain Sensing is briefly described and illustrated with examples. Despite a large number of their own works, the authors try to keep the references as broad as possible. In addition, the essential required fiber optic cable constructions are described and constructive hints for assembly are given. Finally, information on the minimum scope of a measurement report and the evaluation of “Distributed Strain Sensing” measurements are given. In a further contribution, it is planned to provide information on the call for tenders for the “Distributed Strain Sensing” – for measurements in geotechnical engineering – in order to provide the engineer who issued the tender with a tool to enable the planner to obtain the desired measuring method as a result of his contract award. [ABSTRACT FROM AUTHOR]

TIMpuls basic research on fire protection in timber construction: charring rate, protection times of claddings and post‐burning behaviour of timberThis paper presents excerpts from first results and experiments within the TIMpuls research project on charring rate of timber, the performance of fire protection claddings and the post‐burning and extinguishing behaviour of timber components. By means of small‐scale tests, charring rates for various types of timber under standard fire exposure were determined. The investigations of the performance of fire protection systems comprise the state of the art in application and the classification criteria. Based on this, an explanation of the small‐scale test setup and the experimental test results is given. Based on the test results an evaluation of the performance of the fire protection claddings is presented. Furthermore the behavior of timber structures in the decay phase of a fire is investigated. Here, boundary conditions for achieving self‐extinguishing in a fire compartment, experiences with the extinguishing process and constructive measures to avoid cavity fires are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Thermal material properties of fire protection materials for natural fire scenarios In this paper experimental investigations regarding the thermal behaviour of selected fire protection materials (FPM) for steel elements exposed to natural fires are presented. Material properties, such as specific heat, thermal conductivity and density of FPM, have not been investigated in detail yet, especially for natural fire scenarios with different heating and cooling rates. For this purpose, experimental investigations of material properties of perlite plaster, gypsum fire protection boards and intumescent coatings will be presented. Currently, the determination of the thermal behaviour is based on investigations under the standard fire curve (ISO 834). For this approach, the thermal material properties of the FPM are not required. In addition to the standard fire design, the Eurocodes also enable a performance‐based design for a natural fire scenario. In contrast to the standard fire, which assumes a rapid and continuous rise in temperature, a realistic model of a fire (development phase, fully developed fire, cooling phase) is presented. The natural fire curve depends on fire loads, ventilation conditions and room configuration. Therefore, the properties of FPM for natural fires cannot be obtained from the standard fire tests. For the performance‐based design of protected steel components under natural fire the temperature‐dependent thermal material properties are therefore indispensable. [ABSTRACT FROM AUTHOR]

Abstract: Comparative study of approaches for identification of passing trains from measurements Civil engineering structures are mostly unique. Stochastic properties of acting loads and the corresponding structure reaction can be determined by help of long‐term measurements. The identified loads and reactions can further be used in validation and assessment procedures to analyze static and dynamic behavior of the structure. Three reinforced concrete poles located along the new high‐speed railway track Erfurt–Leipzig have been equipped with a monitoring system in the framework of the DFG founded Research Training Group 1462. The goal of the monitoring system is to identify influence of passing trains on the structural behavior of the poles. The measurement record is controlled by two photoelectric sensors. However, due to different disturbing factors fault detections of train passing are possible. Therefore, the obtained measurement data at first step must be classified with respect to actual train passing. Additionally, to simplify analysis of a huge amount of upcoming data, a classification algorithm should work automatically. In this paper, we present a comparative study of train identification methods based on tools of signal analysis compared to the identification based on the signals of photoelectric sensors. Especially, Fast Fourier Transform and Gabor Transform are applied to the time‐history records from the soil pressure and acceleration sensors. [ABSTRACT FROM AUTHOR]

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: 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: 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]

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]

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]

Nachrichten Deutscher Bautechnik‐Tag 2019 in Stuttgart – Call for Papers Kooperation „Digitale Städte und Regionen“ stellt sich vor Auslobung Bayerischer Ingenieurpreis 2019 [ABSTRACT FROM AUTHOR]

Composite dowels can be used as a powerful alternative to headed studs for the efficient combination of ultra-high performance concrete (UHPC) with high-strength steel in modern steel-concrete composite structures. Besides sufficient shear resistance, the composite dowels have to ensure the transmission of tensile forces in the composite connection in order to prevent lifting of the concrete slab. In particular, in the very slender concrete slabs of high-strength composite beams, in which the composite dowels have very small embedment depths, this can lead to structural problems. While initial findings concerning the structural anchorage behavior of composite dowels under static loads already exist, studies on the fatigue of composite dowels under cyclic pull out loading are still lacking, so far. The present paper presents static and cyclic pull out tests of composite dowels in UHPC slabs. While the influence of different embedment depths as well as the use of a transverse reinforcement have been investigated in the experiments under static loading, the cyclic tests particularly focused on load-dependent parameters (upper load level and load range). Finally, an approach to estimate the lifetime of composite dowels in UHPC under cyclic pull out loading is proposed. [ABSTRACT FROM AUTHOR]

In the summer of 1937 the eastern part of the Berlin highway circle was opened to traffic. Thus one of the later on best known bridges was put into use. It seems to be a little bit confusing, that a majority won't remember the bridge because of its size, but rather of its disruption. Consequentially you can find very few neutral papers about this structure. [ABSTRACT FROM AUTHOR]

During river floods it has often been observed that bridges could obstruct the flow of the water and enhance or cause inundations of the adjacent areas. In this paper some significant principles of the constructional design of bridges are discussed from a hydraulic engineer's viewpoint to ensure the erection of useable and durable structures. [ABSTRACT FROM AUTHOR]

A change in the ship traffic volume is expected as a result of upgrading of many European waterways. There is a correlation between an improved waterway passage, an increased ship size and higher frequency of larger ships. On the one hand, the ecological and economic advantages of the upgrading process cannot be disputed, but on the other hand, the changed shipping traffic results in additional risks, especially to bridge substructures. Most of the current bridges were built more than 30 years ago and were generally not dimensioned for horizontal forces expected from a ship impact according to modern codes. This paper provides some information on theoretical background of ship impact analysis and challenges associated with numerical modelling. In particular, it also provides two case studies of historical bridges over river Main. A detailed discussion of provided structural solution is provided along with recommendations. [ABSTRACT FROM AUTHOR]