13 results
Now showing1 - 10 of 13
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Experimental investigations on shear failure in RC slabs subjected to distributed and concentrated loads - Technical Report(Technische Universität Hamburg, Institut für Massivbau, 2024-10); ; ; Versuchsbericht über eine Versuchreihe zum Thema Querkrafttragfähigkeit von Stahlbetonplatten ohne Querkraftbewehrung unter kozentrierten Lasten und zusätzlichen gleichförmigen Lasten.Publicationtype: Technical Report49 70 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , New approach for shear design of reinforced concrete slabs under concentrated loads based on tests and statistical analysis(2020-09-15); ; Despite the international research activity, the shear strength of reinforced concrete slabs without shear reinforcement is not yet satisfactorily resolved. In particular, deck slabs of existing bridges often show significant deficits in design shear capacity, although no damage has been reported so far. A test series of 14 large-scale cantilever slabs subjected to concentrated loads was conducted and analysed at the Hamburg University of Technology. Varying the distance between the concentrated load and the support in a previously unexamined wide range led to new considerations regarding the shear capacity in RC slabs. The ultimate and residual loads of the test specimens, as in many other studies on this topic, clearly exceeded the values for vehicle load assumptions in the current standards. In contrast to previous studies, a large shear slenderness in the load arrangement could be realized in the tests. This was the basic requirement for one of the key findings: The critical shear crack occurs locally in the area of load application and not at the support. Thus, shifting the design section for shear close to the concentrated load is reasonable, while in many approaches a critical section close to the support is chosen. Furthermore, the often-used effective width beff, which depends on the distance of single loads to the support, does not seem justified. The shear forces should be determined by finite element analysis, a common method in practice, which can consider the spatial load transfer and the stiffness of the support in a realistic manner. The new design method presented here is therefore not primarily concerned with the shear resistance, as other investigations are, but first on the side of determining the relevant internal shear forces, which are initially higher in the design section proposed here. Only in a second step is a preliminary factor C*Rd,c for the calculated resistance determined by means of a well-founded statistical evaluation. For this purpose, a database with 45 tests on RC slabs has been established. The new design approach provides significant greater shear capacities than the current regulations.Publicationtype: Journal Article181 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Shear design of concrete bridge decks without shear reinforcement(2019-08-22); ; Many older concrete bridge decks in Europe, mostly built without transverse reinforcement, show a significant lack of shear capacity due to increasing traffic loads and changes in design. Strengthening the slabs for shear is difficult and very expensive. Thus, more reliable design methods are urgently needed to overcome the calculated safety deficit and in order to avoid unnecessary retrofitting. In this paper a new design method will be presented which gives at least 40 % higher shear capacities than current design rules (EN 1992-1-1:2004; Eurocode 2 Part 1 (2004), in the following EC2-1). This approach is based on the examination of full-scale tests of cantilever slabs and statistical evaluation of a database with test results of reinforced concrete slabs under concentrated loads. Next, this paper shows the advantages and limitations of probabilistic analysis.Publicationtype: Conference Paper232 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Increasing the design shear strength of concrete bridge decks by tests and statistical analysis of a shear database(2019-06); ; Publicationtype: Conference Paper168 - 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 , Shear Capacity of Concrete Slabs Without Shear Reinforcement Under Concentrated Loads Close to SupportA large number of existing concrete bridge decks in Europe show a deficit of shear capacity according to current design rules. Retrofitting can hardly be done and is very expensive. Thus, new and more reliable design methods are urgently needed. This report describes 8 full-scale tests on cantilever concrete slabs (3.25 × 4.5 m, thickness 0.25 m) without shear reinforcement under concentrated loads. The experimental studies presented in this paper were conducted to get a better understanding of the load bearing behavior of cantilever slabs and to quantify the influence of the direct load transfer of concentrated loads close to line supports.Publicationtype: Conference Paper61 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Versuche zur Querkrafttragfähigkeit von Stahlbetonplatten unter auflagernahen Einzellasten : Versuchsbericht(2017-11-06); Test report on a series of tests on the shear capacity and load transfer of reinforced concrete slabs without shear reinforcement under concentrated block loads.Publicationtype: Technical Report662 504 - 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 , Experimentelle Untersuchungen zum Lastabtrag konzentrierter Blocklasten in Stahlbetonplatten ohne QuerkraftbewehrungBei der Nachrechnung von Brücken treten in Fahrbahnplatten aus Stahlbeton häufig rechnerische Defizite bei der Querkrafttragfähigkeit auf, da diese im Allgemeinen keine Bügelbewehrung aufweisen. Ein zentrales Thema ist dabei der Lastabtrag der konzentrierten Radlasten, die aus dem Lastmodell 1 (LM1) des Eurocode 1 resultieren. Um das Tragverhalten zu untersuchen wurden am Institut für Massivbau der TU Hamburg insgesamt 14 auskragende Stahlbetonplatten (im Grundriss 3,25 m 4,50 m, h= 25 cm) ohne Querkraftbewehrung unter konzentrierten Blocklasten getestet und numerisch simuliert. Hierbei wurden der Einfluss der Laststellung, die Bewehrungsmenge sowie die Überlagerung mehrerer Lasten untersucht. Anhand von Messungen der Dickenänderung ließ sich die Rissentwicklung innerhalb der Platten erfassen. Mit Hilfe numerischer Berechnungen wurden das Tragverhalten und die Rissentwicklung der Versuchskörper eingehend studiert. In diesem Beitrag wird exemplarisch die Simulation für einen ausgewählten Plattenversuch im Detail erläutert und anhand der wesentlichen Messwerte validiert. Es ergeben sich gute ÜbereinstimmungenPublicationtype: Conference Paper92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Determining the shear force in roadway slabs of steel and pre-stressed concrete bridges(2014-12-01); Publicationtype: Journal Article4