Material Properties of Ultra High Performance Concrete (UHPC) at High Strain Rates The presented paper is a contribution to the material description of Ultra High Performance Concrete (UHPC) under high-speed dynamical loading conditions. Based on a series of Hopkinson-Bar experiments dynamical material parameters such as the Tensile Strength, Young's Modulus and Fracture Energy are derived at high strain rates of 10(2). s(-1). A comparison with the results of these parameters for normal and high strength concrete leads to a qualitative and quantitative evaluation of UHPC at high strain rates. With the extension of the established RHT material model for UHPC by the material's Fracture Energy and Stress-Crack-Opening-Relation the Hopkinson-Bar experiments are simulated appropriately
Ultra-high-performance concrete (UHPC) is particularly suitable for application in aircraft-impact-resistant high-rise buildings for combined load-bearing and protective structures. The material provides very high-steel-like-compressive strength, sufficient ductility, and fire resistance due to the addition of steel and polypropylene fibers. The following contribution is focused on two key aspects: hydro-code simulations of structural UHPC walls which protect vertical escape and rescue routes and structural dynamic simulations of the global structure to investigate the impact resistance considering the sudden loss of external columns. A high-speed dynamic material model for UHPC is obtained by implementing the results of a series of Hopkinson-Bar experiments which were recently published. The strain-rate-dependent material properties are implemented in the established RHT-Concrete-Model for hydro-code applications being furthermore extended by a tensile softening law fo r fiber-reinforced UHPC. Based on this material model a series of aircraft-engine impact experiments are configurated supported by three-dimensional nonlinear hydro-code prognosis simulations. With a total of six impact experiments on combined fiber- and rebar-reinforced UHPC panels, all relevant damage states of the structural wall are obtained. The experimental results are compared to the hydro-code prognosis simulations to validate the simulative approach and the material model for UHPC. In addition to the local impact behavior, structural dynamic numerical simulations of a global high-rise structure are presented being focused on the effect of the sudden and notional loss of columns in coincidence with the aircraft impact load function
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Die Bauwirtschaft erfährt durch die Digitalisierung (Building Information Modeling, BIM) eine Veränderung und Weiterentwicklung ihrer Arbeitsmethoden und Prozesse. Seitens der Politik (Stufenplan des BMVI) und der Auftraggeber großer Infrastrukturmaßnahmen (u. a. Deutsche Bahn, DEGES) wird die Methode ab 2020 in der Leistungsniveaustufe 1 verbindlich eingeführt. Die hiermit einhergehende Planung, Bauausführung und der Betrieb von Ingenieurbauwerken mittels digitalen Modellen erfordert deutlich veränderte, über die bisher definierten Leistungsphasen hinausgehende, stärker kooperative und vereinheitlichte Arbeitsweisen. Für diese gilt es neue Anforderungen, Abläufe und Ziele zu definieren, welche die Bearbeitungstiefe, die Zusammenarbeit und die Dokumentation der Leistungen regeln. Die im Rahmen einer Vielzahl von Projekten zum BIM-gerechten Entwurf von Brücken gewonnen Erkenntnisse der TH Köln und der Schüßler-Plan Ingenieurgesellschaft werden im diesen Beitrag zusammengefasst und sollen zur angemessenen Anwendung und weiteren Entwicklung der Methode beitragen.
Within the design of reinforced concrete against explosive threats only a subjective or a lump safety is currently considered. Therefore the established safety is unknown. For the estimation of the existing safety of present approaches the SDOF approach has been linked to the first order reliability method, which allows for a derivation of the given reliability. Hereby it could be proven that the considered safety is, compared to the claimed reliability of the Eurocode (EC0), deficient
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