A growing interest for the design of structures to sustain blast-induced loads has been observed in recent years as a result of the worldwide rise of terrorist bombing attacks. The blast loading is usually characterized by a sudden increase in the pressure followed by an exponential decay. The parameters of this pressure pulse are essential for design and can be found in various blast design manuals available in the open literature. One of the most widely used sources is a technical report by Kingery-Bulmash, which provides values for many blast parameters in diagrams and polynomial form. However, it does not include an equation for calculating the blast wave decay coefficient, necessary for constructing the pressure-time history of an explosion at a certain point. In this study, a review of the technical literature that contains expressions for the blast pressure decay coefficient is performed, and relevant comparisons have been made. New equations describing the decay coefficient of the Friedlander equation for both incident and reflected cases for free-air and surface bursts are proposed. These equations express the decay coefficient in terms of the scaled distance and are not valid for close-in detonations. They are entirely based on the Kingery-Bulmash data, and their accuracy is satisfactorily checked against new experimental results and their trends assessed through a sensitivity analysis. Accordingly, the positive phase of the pressure-time curve at a point can be reliably and efficiently generated.

A growing interest for the design of structures to sustain blast induced loads has been observed in recent years due to the worldwide rise of terrorist bombing attacks. The blast parameters that are essential for design can be located in various publically available blast design manuals, where the proposed graphs and equations are based on a large experimental database established several decades ago. The degree of uncertainty in the determination of these parameters is significant, as a result of the unstable nature of explosives, the efficiency of the measuring equipment and the large pressure and impulse values involved in the blast phenomena. These uncertainties have been identified in the current study which focuses on the response of steel open sections under blast induced loads and addresses the influence of such uncertainties on the flexural response of axially loaded structural members. The variation of structural and load parameters was considered in the design procedure by utilizing a reliability-based assessment methodology. A probabilistic approach was followed and the reliability of the column was defined with respect to limit states proposed in various blast design manuals. Probability curves are constructed, by using single-degree-of-freedom models, showing the cumulative probability distribution of reaching a certain capacity with respect to a selected limit state. This way instead of a deterministic safe-unsafe criterion in design, the probability of damage is introduced in relation to the applied axial load, which provides a valuable insight to the behaviour of structural members subjected to an explosion.

This report deals with the results of an international research project ”Plastotough”, the aim of which is to discover the toughness requirements for structural steel to make it suitable for plastic design for ”static loads” and for loads that vary over time, as from seismic events. These toughness requirements should be specified as the Charpy energy value KVUS in the upper shelf domain of the toughness‐temperature diagram and as the extension of KVUS to the minimum temperature TUS for which it is still valid. This report, after recalling empirical rules for toughness requirements, first gives the methodological tools from fracture mechanics and damage mechanics to tackle the task. The use of these tools is connected with experimental tests on specimens that are detailed such that they are representative of local (from notch effects) and global (from plastic hinges with plastic rotations) ductility demands. The steels for the test specimens were taken from regular ”European production”; rolled sections in particular exhibit a quality level that far exceeds the minimum requirements of EN 10025. For the steels considered, it was proved that they follow the EricksonKirk correlation between the T27J values and TUS so that they can be classified in a group of steels together with pressure vessel steels and naval steels. All strain requirements from local strain raisers and from global plastic rotations could be met on the safe side using the fracture mechanics and damage mechanics resistances determined for these steels. For seismic design in particular it could be shown that the cracking associated with ultra‐low‐cycle fatigue is not relevant for buildings if the behaviour factor q is determined using reasonable limits for inter‐storey drift. Therefore, the key conclusion is that for the safe use of plastic design in ”static” and ”seismic” situations, the elevated level of toughness quality of steels usually available from European producers must be used. To this end it is recommended to specify these steels either in the context of brandnames or by additional options in EN 10025.

In response to the heightened terror threat in recent years, there is an increasing interest in the introduction of access control zones at sites that are characterized by an increased likelihood of being the target of a terrorist attack, as latest data reveal that unprotected areas of mass congregation of people have become attractive to terrorist groups. Such control zones could be located within the building that has to be protected or attached to it. The elevated security needs for these areas call for a design that will consider the risk of internal explosive events. The purpose of this article is to outline a strategy for limiting the consequences of an internal blast, while guaranteeing that the produced blast wave does not propagate into vulnerable areas. In particular, the focus is on the introduction of a protective wall system in the form of a meander that allows unobstructed access of the public and at the same time reduces the possible blast inflow to the building's interior. The performed numerical simulations show that the proposed strategy yields much smaller injury risk areas compared to a design without the addition of protective walls and is recommended for upgrading the security of buildings.