This research programme was carried out to investigate the behaviour of high-strength concrete plates subjected to impact loading. The research includes an experimental investigation on 16 concrete plates. A rigid projectile was used to apply the impact load to the tested reinforced concrete specimens. The rigid projectile consisted mainly of a solid steel cylinder with 220 kg mass and 304·5 mm dia. contact area, dropped at variable heights of up to 4 m. The structural behaviour with respect to deflection, concrete and steel strains, failure mode and energy absorption was examined. The effects of dynamic loading, concrete strength, reinforcement ratio and support pattern were the test parameters. Based on the experimental test results, it has been found that at a test velocity of 4−7 m/s the impact load is about twice the static punching shear capacity estimated from code provisions.

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This study is aimed to discuss structural behavior of steel reinforced sandwich concrete beams (SWB) consisted of skins and a core. The skins were made of ordinary concrete and a core was of pumice lightweight concrete. The SWB skin compressive strengths of 30 MPa and the core compressive strength of 15 MPa were considered. Twelve SWB specimen of 150x250x2500 mm with 50 mm skin thickness and 150 mm core thickness were cast and tested after curing process under flexural points loading as simply supported beams. All the beams considered were reinforced with 3D12 mm deformed bar and 8 mm stirrups with 3 spacing variations. Shear span depth ratio (a/d) of 1.8, 2.3, 2.8, and 5.4 were also considered to reflect the behavior between short and slender beams. Results showed that the flexural behavior of sandwich beams were identical with normal or lightweight concrete beams behavior. Ultimate moment of beam section slightly increased with increasing the shear span to depth ratio, which were varies between 1.26 and 2.31 of the calculated moment. The yield moment to the ultimate moment ratio vary between 0.83 and 0.99. The ductility was increased with the decreased shear reinforcement spacing. The shear strength increased as the spacing of shear reinforcement decreases in almost all a/d variations. Shear strength was also increased with the increase of a/d ratio for short beam and the other hand shear strength decreased with the increasing a/d.