Parametric study of concrete sandwich walls subjected to impulse loading: A study to evaluate the important properties of a blast loaded concrete sandwich wall

Abstract

Energetic materials in densely built environments possess a high risk in the case of ignition. It is therefore of interest to understand the response of surrounding structures subjected to blast loading. One common wall structure is the concrete sandwich wall, composed of two reinforced concrete layers separated by an intermediate layer of insulation. This thesis describes the response of such a wall composition subjected to an impulse load. Additionally, the effect of the intermediate insulation layer is investigated to emphasise its potential energy-absorbing effect. Different models were developed to describe the behaviour of a concrete sandwich wall: two simplified mass-spring models (SDOF and MDOF) and one 2D Finite element model. The models were compared to highlight their strengths and weaknesses. A parametric study, including material properties and geometry, investigated the favourable effects and potential benefits of the intermediate layer. All models display a similar response when studying deflections, energy distribution and load transfer. The MDOF and FE model can describe the response of the wall composition in more detail. The parametric study found that the intermediate layer has an energy-absorbing effect, reducing the deflection. The yield stress of the intermediate layer greatly influences the structural response. Various factors, such as wall geometry, load magnitude, and insulation thickness, influence the optimal yield stress. Utilizing optimized parameters of the intermediate layer can be beneficial when designing walls subjected to severe loading. However, implementation can be difficult since the favourable effect depends on numerous factors. Additionally, some simplifications must be investigated further, such as the effect of shear connectors connecting the outer and inner panels.