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Item type:Publication, Access status: without files , Intelligente digitale Methoden zur Verlängerung der Nutzungsdauer der Nibelungenbrücke(Ernst & Sohn, 2025); ; ; ; Intelligent digital methods for extending the service life of the Nibelungen Bridge. To extend the service life of structures while maintaining their structural safety and functionality, effective monitoring and maintenance concepts are necessary. Within the scope of the Priority Program 2388 “Hundred Plus – Extending the Service Life of Complex Structures through Intelligent Digitalization” (SPP 100+), funded by the German Research Foundation (DFG), interdisciplinary methods including digital models, digital linkages, and condition indicators, have been investigated and validated on the Nibelungen Bridge in Worms. First, two structural health monitoring systems and their combination are described in detail, with particular focus on the fusion of accelerometer data. Subsequently, innovative data-driven simulation methods are presented to determine the complete temperature field of the bridge superstructure. In addition, various numerical solutions covering different element types and levels of detail are introduced. Finally, methods for managing knowledge about the bridge's condition are presented. The methods were developed relatively independently of each other and validated at the NBW. In the next step, all methods will be integrated to support the maintenance of the NBW.Publicationtype: Journal Article28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , openLAB – Eine Forschungsbrücke zur Entwicklung eines digitalen Brückenzwillings(Ernst & Sohn, 2024-01-11)52 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Rissreibung in Biegeschubrissen(2023-07); Aggregate Interlock in critical shear cracks. Numerous models have been published for estimating the shear capacity of reinforced and prestressed concrete members without transverse reinforcement. Some approaches assume that the shear force is essentially carried by crack friction. Others consider the uncracked concrete compression zone as the governing load-bearing mechanism. To address this question, 10 tests were conducted on reinforced concrete beams without stirrups. The focus of the tests was to record crack development and to measure crack opening and crack sliding. Using conventional and modern measurement methods, such as digital image correlation (DIC), the load-bearing behavior was extensively recorded and evaluated. Furthermore, the crack surfaces were inspected and the shear friction was calculated. According to the conducted investigations, crack friction carries only a small proportion of the total shear force. The results of the research project thus contribute to a better understanding of shear force transfer in reinforced concrete members without shear reinforcement.Publicationtype: Journal Article48 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Querkrafttragfähigkeit von Stahlbetonplatten ohne Querkraftbewehrung unter konzentrierten Einzellasten: Teil 2: Vorschlag für ein neues Bemessungskonzept(2019-04); ; Shear capacity of reinforced concrete slabs without transverse reinforcement under concentrated loads. Part 2: Proposal for a new design model. Despite intense national and international research activities, the shear capacity of reinforced concrete slabs without shear reinforcement has not yet been satisfactorily clarified. Numerous older deck slabs of concrete bridges show a lack of shear resistance in the transverse direction. Retrofitting is hardly possible. In this paper, a design model is presented on the basis of tests and statistical investigations, which results in approx. 50 % greater shear capacities than according to current regulations.Publicationtype: Journal Article254 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Ermüdungsfestigkeit zyklisch beanspruchter Stahlbetonbalken ohne Querkraftbewehrung(2018-05); 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.Publicationtype: Journal Article170 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Querkrafttragfähigkeit von Stahlbetonplatten ohne Querkraftbewehrung unter konzentrierten Einzellasten - Teil 1: VersucheShear capacity of reinforced concrete slabs under concentrated loads – Part 1: experimental investigations. A large number of the deck slabs of existing concrete bridges in Europe show, according to current design rules, a deficit in shear capacity. Strengthening is in most cases difficult and very expensive. The authors are not aware of any real structural failure of bridge decks caused by a lack shear capacity, when the structure was designed properly. This is an indication that the existing design approaches have unknown reserves and the transverse load bearing capacity of reinforced concrete slabs is not sufficiently understood and clarified. Extensive international research activities on this subject confirm this fact. Up to now, there is no consensus regarding the design method (shear or punching), the relevant section, and the reduction of the shear force caused by block loads close to supports (β-factor). Fourteen large tests were carried out on cantilevered concrete slabs (3.25 × 4.5 m, thickness 0.25 m) without transverse reinforcement, as well as extensive numerical simulations. The design shear capacity of bridge decks is decisively determined by the concentrated wheel loads of heavy traffic. Thus, the test specimens were loaded by concentrated block loads on an area of 40 × 40 cm according to the load model 1 of the Eurocode 1 [1] up to failure. The influence of the load position, the mutual interference between adjacent block loads, as well as the influence of different reinforcement ratios on the shear capacity were investigated. The test results show that conventional deck slabs of concrete bridges have considerably greater load bearing capacities than according to EC2[2].Publicationtype: Journal Article127 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Ein Beitrag zur Konstruktion und Bemessung von Segmentbrücken(2013-03-27); Das Trag‐ und Verformungsverhalten von segmentären Hohlkastenbrücken mit Trockenfugen wird für verschiedene Laststellungen und Tragsysteme erläutert. Es zeigt sich, daß die Steifigkeit der Konstruktion wesentlich von den Fugen zwischen den Fertigteilen beeinflußt wird. Der Schwerpunkt der weiteren Untersuchungen liegt daher in der Bestimmung des Kräfteverlaufes im Bereich der unbewehrten geschlossenen bzw. offenen Fugen. Auf der Basis von numerischen Berechnungen und Versuchen wird ein Modell zum Nachweis der Schubtragfähigkeit der Fuge vorgestellt, welches eine erheblich wirtschaftliche Bemessung dieses kritischen Bereiches als nach ermöglicht. Weiterhin werden die Vor‐ und Nachteile der verschiedenen Fugenausbildungen diskutiert.Publicationtype: Journal Article124 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Versuche zur Querkrafttragfähigkeit von gevouteten Stahlbetonbalken ohne QuerkraftbewehrungThe shear capacity of concrete members without transverse reinforcement is still under debate. Within this paper one aspect, the favourable contribution of inclined tension and compression chords (Vtd and Vccd) of members with variable depth, like haunched beams, will be discussed in detail. A series of 18 tests on 9 different specimens was performed to examine the real shear capacity of haunched beams without shear reinforcement. The evaluation of the test results revealed, that none of the available design methods can describe the shear behaviour of haunched beams. The vertical component of the inclined compression chord Vccd leads in some cases to unsafe values.Publicationtype: Journal Article66 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Querkrafttragfähigkeit von Fahrbahnplatten ohne QuerkraftbewehrungThe design of concrete bridge deck slabs is of major concern since the introduction of the Eurocodes as the calculated shear capacity of slabs without stirrups and staggered reinforcement according to the new design standards is often considerably smaller compared to the former regulations i.e. DIN 1045:88. This raises the question whether the existing structures are still save. A series of 12 tests on 4 different specimens representing a bridge deck was performed to examine the real load bearing behaviour of a slab with and without shear reinforcement under a wheel (point) load. The evaluation of the test results revealed, that the current design formula with an assumed elastic shear force distribution leads to rather conservative values of shear capacity for bridge deck slabs. Various approaches for shear design are discussed and the accuracy is checked by means of a shear database and the test results. A new model to calculate the shear capacity is proposed which shows a better agreement with test data than the known approaches. © 2009 Ernst.Publicationtype: Journal Article68 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Probleme bei der Berechnung von Stahlbetonkonstruktionen mittels 3-dimensionalen Gesamtmodellen [Design of three-dimensional finite elements models]In der Praxis werden für die Berechnung von Stahlbetontragwerken immer häufiger dreidimensionale Finite‐Elemente‐Modelle des gesamten Tragwerkes (Gesamt‐ oder Gebäudemodelle) verwendet, wobei teilweise auch das stofflich nichtlineare Materialverhalten des Betons berücksichtigt wird. Dabei wird oftmals den Ergebnissen des Rechenprogramms blind vertraut. Aus Zeitgründen unterbleiben die unbedingt notwendigen Kontrollen ebenso wie eine übersichtliche Dokumentation der wesentlichen Rechenergebnisse. Diese Entwicklung bietet Anlass zur Sorge im Hinblick auf die Tragsicherheit der Bauwerke. In diesem Beitrag werden an einer relativ einfachen Tragstruktur, einer Bogenbrücke, die Schwierigkeiten erläutert, welche bei komplexen FEBerechnungen auftreten können. Es wird verdeutlicht, dass eine automatische, programminterne Bemessung von Stahlbetontragwerken nicht möglich ist. Die Ausführungen sollen dazu dienen, dem Tragwerksplaner die Notwendigkeit einer eingehenden Prüfung der Ergebnisse zu vermitteln.Publicationtype: Journal Article79