Air-blast-loaded, high-strength concrete beams. Part I: Experimental investigation

Abstract

The structural behaviour of concrete beams subjected to air blast loading was investigated. Beams of both highstrength concrete (HSC) and normal-strength concrete (NSC) were subjected to air blasts from explosives in a shock tube and for reference were also loaded statically. Concrete with nominal compressive strengths of 40, 100, 140, 150 and 200 MPa were used and a few beams also contained steel fibres. Furthermore, beams with two concrete layers of different strength were tested. All beams subjected to static loading failed in flexure. For some beam types, the failure mode in the dynamic tests differed from the failure mode in the corresponding static tests. In these cases, the failure mode changed from a ductile flexural failure in the static tests to a brittle shear failure in the dynamic tests. Beams without fibres and with high ratio of reinforcement exhibited shear failures in the dynamic tests. It was observed that the inclusion of steel fibres increased the shear strength and the ductility of the beams. The investigation indicates that beams subjected to air blast loading obtain an increased load capacity when compared with the corresponding beams subjected to static loading.

Prediction of the impact force on reinforced concrete beams from a drop weight

“…Previous studies reported that RC beams failed statically in the pure flexure mode may shift to the shear failure mode in impact tests (Magnusson et al, 2010a(Magnusson et al, , 2010bMicallef et al, 2014;Ozˇbolt and Sharma, 2011;Saatci and Vecchio, 2009). Hughes and Beeby (1982) pointed out that shear failure may occur in RC beams due to activation of higher modes of vibration under impact loads.…”

Air-blast-loaded, high-strength concrete beams. Part II: Numerical non-linear analysis

“…In the simulations, the air blast load was applied as a piece-wise linear approximation of a registered pressure-time curve obtained from the experiments (Magnusson et al, 2009). Ten data points were used to describe the amplitude of a pressure load on the surface, which thus varies linearly over time between data points, as shown in the example given in Figure 1.…”

“…1 mm respectively. The distance from the bottom surface of the beam to the centre of the tensile rebars was 33 mm, which is the nominal measurement for the beams in the experiments (Magnusson et al, 2009). A modelled beam with five rebars of diameter 16 mm and with an interface layer around each rebar is illustrated in Figure 5.…”

“…An introductory theoretical investigation on the behaviour of reinforced concrete beams subjected to air blast loading has been performed by Magnusson and Hansson (2005a). The present paper describes the development of the numerical methodology used for evaluation of the test results presented in a companion paper (Magnusson et al, 2009). It is especially interesting to investigate the possibility of numerically analysing the dynamic behaviour of air-blast-loaded concrete beams, and focus on the influences of concrete strength, amounts of reinforcement, the bond between concrete and reinforcement, material strain rate effects, bi-linear strain softening of concrete and strain rate dependence of the reinforcement.…”

Performance of Fiber Reinforced High-strength Concrete with Steel Sandwich Composite System as Blast Mitigation Panel

“…Besides the steel, the concrete material also has a significant contribution in determining the panel's performance. Previous studies concluded that HSC is too brittle to achieve its full strength potential [5,8]. The incorporation of fibre is a good way to overcome the brittleness of plain HSC.…”