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Item type:Publication, Access status: without files , BIM in construction(Fédération internationale du béton (fib), 2025-02-01); ; Srinivasan, GopalIn recent years, Building Information Modelling (BIM) methodology has seen exponential growth in its adoption within the construction industry. Despite its tentative beginnings in a sector traditionally resistant to major changes, the undeniable advantages it offers have made all stakeholders, from designers to builders, including government authorities and facility maintainers, aware of the need to embrace the full implementation of BIM standards in the sector. Nonetheless, the adoption of BIM methodology presents its own set of challenges. Despite not being a novel approach, BIM has not reached a level of maturity where a universally accepted standard or a singular implementation method has been established. The multitude of BIM use cases is steadily expanding alongside a growing variety of applications, increasing expertise, and the continuous enhancement of software capabilities. The document management aspect associated with BIM methodology represents its true potential. This entails the ability to centralise the geometry and all attributes associated with an element within a single element that can be shared and interacted with by all stakeholders. This management poses an additional challenge, as it requires clear protocols to ensure that information is exchangeable and exportable between parties. Standardisation within a given market will be much simpler if government authorities establish the standards. Attempting to compile a comprehensive document on the state of the art of BIM methodology would be a daunting and potentially unproductive task, given that new papers with innovative BIM applications and uses emerge practically every week and with the increasing number of specialised books. Moreover, professionals responsible for designing, constructing, or maintaining structures derive limited benefit from an overly lengthy document that encompasses all possibilities. Therefore, the objective of Task Group 1.7 (TG 1.7) has been to present concepts that enable readers to gain a basic understanding of the methodology that is sufficiently up-to-date, along with specific examples of its use in various types of structures with varying degrees of complexity. The aim has been to show that BIM usage can range from a specific element of a project to the complete life cycle of a structure, allowing stakeholders to choose what suits their needs best. The fib Task Group 1.7 is confident that this document will be a useful resource for construction professionals, bringing BIM methodology into their everyday use and thus making the construction industry more modern, efficient, and sustainable.Publicationtype: Book37 - 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 Report48 69 - 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 Article47 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Discrete crack propagation analysis of reinforced concrete beams under shear(2023-06-12); The investigation of crack growth in concrete structures without shear reinforcement is an active field of research for decades. To date, there is no consensus on the influence of the critical shear crack and its contribution to the shear force transfer, so that numerous shear force models take its magnitude differently. While one group assigns the largest amount mainly to the compression zone and less to the crack friction, the other group assigns it to the crack force transmission due to aggregate interlock. This paper presents an investigation of the influence of the critical shear crack on the load-bearing behavior of concrete beams without stirrups based on a discrete analysis using the extended finite element method (XFEM) for one or more discontinuities (cracks). The concrete damage plasticity (CDP) is used to represent a real material response. For the damage evolution of the discrete cracks, various softening models for the crack process zone are considered (linear, bilinear and nonlinear). The accuracy and computational intensities of different cases are compared. Based on experimental results, it is shown that XFEM in combination with CDP provides realistic data with respect to load-bearing behavior, stresses in the concrete model, crack propagation, crack kinematics, and resulting crack aggregate stresses.Publicationtype: Journal Article34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Shear Failure Analysis with Modelling Multiple Discontinuities in a Concrete Beam Using XFEM(2022-08); Despite intensive research in the last decades, the shear force transfer and crack propagation in structural concrete members is still disputed. In order to investigate the load bearing behaviour, an understanding of crack growth and flow of internal forces is essential. In this context, various techniques have been developed in the recent years to analyze the crack pattern and to detect fracture failure in advance. This paper presents the investigation of discrete crack propagation and the shear bearing behaviour of a concrete beam without transverse reinforcement using the extended finite element method (XFEM). By applying the cohesive zone model (CZM) under different traction separation laws and describing the damage evolution, crack growth is modelled with several discontinuities. In this framework, the load bearing behavior and the development of the crack with its dimensions are discussed. Linear, bilinear and nonlinear softening curves of the fracture process zone for the investigation of one to several cracks are presented. The numerical analysis are validated by experimental results. The findings are compared and evaluated with the isotropic material model ‘concrete damage plasticity’ (CDP). The smeared and discrete crack pattern are contrasted. It is concluded that the numerical analyses make useful predictions of the fracture behavior of reinforced concrete members and provide further possibilities for research purposes.Publicationtype: Conference Paper68 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Untersuchungen zur Kraftübertragung in Rissen von Stahlbetonbalken infolge Querkraft- und Torsionsbeanspruchung : Versuchsbericht(2022-04-10); ; Reinforced concrete beams and slab strips under shear force and torsion loading, respectively were tested in the year 2021 at the laboratory of the Institute of Concrete Structures of the Technical University Hamburg (TUHH). The aim of the research project was to determine the magnitude of the deformations at the entire crack (crack kinematics) and thus also the stress state along the crack faces as a function of various input variables. In particular, it was also to be clarified whether significant crack friction stresses occur. The concrete strains and the crack development were recorded by photogrammetry (DIC) and the steel strains by fiber optic sensors.Publicationtype: Research Report304 302 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 350 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Simulation of crack growth in reinforced concrete beams using extended finite element method(2020-10); Fracture mechanics and the crack propagation in reinforced concrete members is one of the most important approaches to structural safety analysis. Thanks to powerful software and increasingly fast computers, numerical simulation is well suited to analyse even more complex problems, such as crack growth, quickly and economically. In order to validate these analyses in their application, however, it is still necessary to confirm and compare numerous models of load-bearing and material behaviour by experimental investigations. This paper presents nonlinear numerical simulations of bending and shear crack propagation in reinforced concrete beams without transverse reinforcement. The smeared and discrete crack growth of haunched and non-haunched beams is analysed. Compared are the load deformation behaviour and curves which show the crack width in relation with the applied load without building a notch in the structure. The obtained results are presented with different mesh densities. The tests and the numerical simulations will provide a broad interpretation of crack growth and redistribution of inner forces in concrete members. As numerical method to map discrete cracks the extended finite element method (XFEM) is applied. For validation, the crack patterns of real experiments are compared with the results of the different finite element models up to two crack initiations. The evaluation is based on single span beams under bending and shear. The numerical simulations make it possible to predict the fracture behaviour of concrete members and shows good agreement with the experimental results.Publicationtype: Journal Article157 - 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: with files , Untersuchung zum Einflusses von geneigten Druckgurten auf den Querkraftwiderstand : Versuchsbericht(2020); The research report describes the tests carried out at the Institute for Structural Concrete at TUHH in 2018 on tapered reinforced concrete beams to check the influence of the inclined compression strut on the shear capacity. The results show that Vccd may lead to unsafe results.Publicationtype: Research Report308 366