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Experimental and numerical study of high performance concrete columns subjected to fire loading
(2009)
Experimental and numerical study of high performance concrete columns subjected to fire loading
(2009)
Experimental and numerical study of high performance concrete columns subjected to fire loading
(2009)
Ausgehend von einer kritischen Analyse der Materialkennwerte für normalfesten (NFB) und hochfesten Beton (HFB) im Eurocode 2 wurden in grundlegenden Untersuchungen an der BAM exemplarisch für einen HFB die thermomechanischen Materialkennwerte bestimmt, um auf der Basis eines geeigneten Materialmodells das Verhalten von Stahlbetonstützen aus HFB unter Brandbeanspruchung zu simulieren. Die Validierung des Modells erfolgte mittels großmaßstäblicher Brandversuche an belasteten Stahlbetonstützen aus dem gleichen HFB wie in den Materialuntersuchungen. Es konnte gezeigt werden, dass die Festigkeit als charakteristischer Parameter des Materialmodells zwingend auf der Basis instationärer Versuche und nicht aus stationären Versuchen wie bei NFB üblich bestimmt werden muss. Mit den in vorgeschlagenen Materialbeziehungen für HFB wird das Tragverhalten der untersuchten Stützen dagegen deutlich überschätzt, was sich in den numerischen Simulationen insbesondere durch zu geringe Verformungen äußert.------------------------------------------------------------------------------------------------------
Development and Validation of an Advanced Calculation Model for High Strength Concrete Columns Subjected to Fire Loading
Following a critical analysis of the material parameters of normal strength (NSC) and high strength concrete (HSC) presented in Eurocode 2 the thermo-mechanical material parameters of one representative HSC were identified. Using these parameters and based on an appropriate material model the behavior of HSC columns was simulated. The validation of the model was realized through real scale fire resistance tests on loaded columns of the same type of HSC as in the material identification tests. It was found that the strength as a characteristic parameter of the material model has to be identified on the basis of transient creep tests and not of stationary tests, respectively as realized usually for NSC. It could be shown that the structural behavior of the tested columns is overestimated if the numerical simulations are based on the material properties of HSC as proposed in. This feature is expressed especially through insufficient displacements.
Damage and strength reduction of a high performance concrete due to thermomechanical stresses
(2008)
Engineering Modelling
(2019)
This chapter presents the most commonly used approach to analyse the
thermo-mechanical behaviour of concrete structures subjected to high temperatures as in the case of fire loading. Prescriptions of the Eurocode are detailed for the thermal as well as the mechanical analysis. Finally, recommendations from two national (Austrian and German) guidelines give some improvements for Underground infrastructure.
Monitoring of fire damage processes in concrete by pore pressure and acoustic emission measurements
(2011)
This paper presents the combined use of acoustic emission (AE), gas pore pressure and temperature measurements (PT). The simultaneous application of both techniques represents a new methodology in the context of fire spalling and contributes to a better understanding of the mechanisms of fire spalling, particular with regard to the interaction of micro cracking and pore pressure evolution. The study presents fire tests on normal strength concrete specimens with and without reinforcement at ISO Standard fire and at hydrocarbon (HC) fire. Supported by AE-analysis, it can be shown that due to the higher heating rate of the HC-fire in comparison to the ISO Standard fire the damage processes inside the concrete during the exposure are increased combined with augmenting the concrete permeability. As a consequence lower pore pressures were measured. However, despite the lower pore pressures, explosive spalling was observed.