Previous research on statically loaded reinforced concrete beams has shown a clear influence of the shear span-to-depth ratio on the resulting shear failure mode. Large shear spans relative to the depth typically lead to capacities governed by the breakdown of beam action, whereas low ratios result in capacities governed by the remaining or full arch. Experimental tests with static loading have determined limits for these ratios and the corresponding failure mode. However, no corresponding limits exist for reinforced concrete beams subjected to high strain rates. This is especially true for deep and short beams, for which test data remain scarce. Impact tests were conducted to study shear span-to-depth ratio limits and corresponding shear-type failure modes at high strain rates. Deep, short, and slender beams were tested to study differences in response. Crack development and deformations were analysed using high-speed photography and digital image correlation (DIC). The series consisted of 27 scaled beams tested under static and impact loading, with varying amounts of transverse reinforcement. Results indicated similar shear failure modes for static and impact-loaded beams across the tested shear span-to-depth ratios. For slender beams, inertial forces and undamaged direct struts dominated early, resulting in higher reaction and internal forces for impact-loaded beams. As deformation developed, the response during both load types was similar, with stiffness dominating and flexural and flexural-shear capacities governing the resistance. Strut and tie models generally aligned with the experimental results, while sectional models were over-conservative. A design procedure based on strut and tie modelling was proposed to capture both early transient and quasi-static phase capacities.

Med syfte att frigöra attraktiv markyta för ny bebyggelse finns det imånga svenska städer idag ett önskemål att förtäta den befintliga stadsmiljön. En sådan åtgärd kan dock resultera i minskade avstånd mellan byggnader och transportled, vilket kan medföra ökade krav med hänsyn till bland annat explosioner. För att skapa en optimal helhetslösning för sådana olycksscenarion behöver de tre delområdena riskhantering, explosionslast och strukturrespons samordnas på ett korrekt sätt. I dagens explosionshantering finns dock betydande brister bland både riskanalytiker och konstruktörer, något som ofta beror på otillräcklig kommunikation och kunskap.

In the present paper, the walls of a concrete frame used for over-decking in a road tunnel were first designed using the relevant design provisions. The response of the wall was then analysed using non-linear finite element analysis, and the results of the finite element analysis were compared to what was predicted using the design guidelines. Additionally, simulations of the blast load resulting from gas leakage during transportation were conducted as a separate study. The results from two vapour clouds containing gases of hydrogen and propane were compared.