Risk assessment due to terrorist actions on public transportation networks : a case study in Portugal

The work presented in this paper was performed in collaboration with one of the largest Public Transportation Operator in Portugal and addresses the problem of risk assessment due to terrorist actions involving explosions at different levels. First, a region of the Operator is selected. The elements in the Operator's network with the highest associated risk are highlighted for each threat using the COUNTERACT guidelines. Subsequently, from the group of elements with the highest associated risk, an element is selected for structural safety evaluation under blast loading. Through numerical analysis, different explosion scenarios are studied and the behavior of the structure is presented.This work was performed under Project CH-SECURE, with reference PTDC/ECM/120118/2010, funded by the Portuguese Foundation of Science and Technology - FCT. The authors acknowledge the support. The first author also acknowledges the support from his PhD FCT grant with the reference SFRH/BD/45436/2008

The response of glass window systems to blast loadings: An overview

The failure of glass windows in terrorist bombing attacks and accidental explosion incidents has been cited as one of the major causes to the vast casualties. Many studies have been carried out to investigate the response and vulnerability of glass windows against blast loadings. These include laboratory and field tests that have been carried out to experimentally study glass window performance under explosion scenarios and development of analytical and numerical models to analyze and predict glass window responses. This article reviews literatures on the studies of the response of glass window systems to blast loadings. Over 100 papers and documents that are available in the open literature are reviewed. The background and history of the studies on the topic are also briefed. Understandings about the dynamic material properties of glass and available material models are summarized. Popularly used analysis methods and design standards for monolithic and laminated glass windows are outlined, and their accuracies are discussed. Recent studies including analytical solution, numerical simulation, and experimental investigations on glass window systems are summarized. Mitigation measures for blast-resistant windows are also briefly discussed

Simplified analysis of foam cladding protected reinforced concrete slabs against blast loadings

Protection of infrastructure against blast loading has been receiving more attention in recent years due to occasional engineering explosion accidents, e.g., chemical plant explosion, and intentional man-made explosions, e.g., rising terrorist attacks. An effective solution to mitigate blast effects on these buildings is to protect them with sacrificial foam claddings for absorption of blast energy. However, little research has been conducted to analyze the effectiveness of metallic foam protected reinforced concrete (RC) structural members under airblast loads. This paper is to develop a numerical model to analyze the mitigation of blast effects on foam cladding protected RC members with consideration of interaction of blast load, foam layer and protected structural member. This numerical model is a simplified SDOF system where the deformability of the RC flexural member is considered in the form of the supporting spring. The stiffness of the spring K is estimated from the resistance deflection function of the RC member which is derived from combined moment curvature and moment rotation models. Material testing was conducted on aluminum foam specimens to obtain the stress stain curve which was idealised as a rigid-perfectly plastic-locking model. The resistance deflection curve of the RC slab and the idealised rigid-perfectly plastic-locking model for foam specimen were incorporated into the coupled SDOF interaction model for dynamic analysis. A field blast testing on foam protected RC slab was conducted and the accuracy of the coupled SDOF interaction model was validated by experimental data from the blast testing of the foam protected RC slab.Chengqing Wu, Yun Zho