Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil–structure interaction effects are taken into account.

Bridge inspection is a time-consuming, expensive, but indispensable task. In this work, a new semi-automatic workflow for a concrete bridge condition assessment system is developed and discussed. The workflow consists of three main parts merged in the new methodology. The elements are the data acquisition with cameras, the automated damage detection and localization using a neural network, and the resulting engineering condition assessment. Furthermore, a CAD model serves as a base for the later calculations for the condition assessment. Camera images are used for both sub-millimeter crack detection using semantic segmentation by an artificial neural network and a crack localization based on a combination of a photogrammetric workflow including structure from motion (SfM) and the projection as imprinted points directly onto the as-planned CAD mesh. Moreover, an approach for crack width derivation is given. The captured crack width, crack position, and the date of detection represent the input values for subsequent crack monitoring. Thereby, this new concept is proposed as an essential step towards a time-efficient and objective life-cycle assessment of reinforced concrete structures.

In case of an explosion event, secondary risks arise from component debris ejected from affected structures. In particular, concrete and masonry wall elements pose a potential hazard due to their high fragmentation when exposed to blast load. Adequate structural design and blast mitigation measures are crucial to ensure the integrity and robustness of the structure. A polyurea-based coating can increase the strength of the load-bearing structure and reduce the amount and velocity of debris. The general effectiveness of this approach has already been widely demonstrated. However, comprehensive research for this specific application in terms of blast loading is lacking. The paper investigates the factors that influence the behavior of polyurea-coated concrete walls with both experimental and numerical approaches. Experiments are performed with a shock tube representing a far-field detonation scenario. Additionally, a numerical model is implemented in LS-DYNA considering the dynamic, strain rate-dependent material properties of reinforced concrete and polyurea as well as the adhesive bond of the polyurea–concrete interface. The test results are used to validate the adopted simulation model. By comparing the results to uncoated concrete wall panels for both experiment and simulation, the blast mitigation effect of polyurea coating for concrete wall panels is assessed: the coating proved to be effective in preventing the generation of high-speed ejecta and also in limiting, to some extent, the crack propagation in the concrete panel. The results set a ground for further development of recommendations or guidelines for structural protection using polyurea coating.

This paper presents a semi-automated approach for assessing building vulnerability on an urban scale, specifically focusing on floods and heavy rainfall events. The method involves three steps: categorization of buildings using open geodata, development of parametric building models for each category, and probabilistic analysis to generate fragility curves. To overcome the challenge of analyzing individual buildings in a large area, generalized models based on building categories are utilized, reducing computational effort but introducing uncertainties. Probabilistic analyses are conducted by adjusting simulation parameters to address these uncertainties. The approach is applied to a reference area in Berlin as a case study. The results provide valuable insights into the vulnerability of individual buildings within different categories. This research contributes to the field of the vulnerability assessment of buildings by offering a practical and efficient method applicable at an urban scale. It enables informed decisionmaking and the development of risk reduction strategies.

This paper presents an investigation into the design of ammonia tanks for long-duration and high-pressure blast loads. The focus is on cylindrical steel tanks that apply as outer pressure-tight containers for double-walled tanks storing refrigerated liquefied gases. Based on limited empirical data, it is known in the tank industry that these tanks can withstand an explosion pressure up to a peak overpressure of approximately 10 kPa and 100 ms positive load duration. However, there is a growing need to design tanks for higher peak overpressures in order to establish a higher safety standard and accommodate unforeseen future requirements. This paper explores the concept of adapting established steel tank designs to handle high-pressure and long-duration overpressure due to blast events. Numerical analysis is conducted on a representative steel tank geometry subjected to a triangular blast load of 30 kPa with a 300 ms positive load duration. Various load application and calculation options are analyzed numerically. Considering the challenging nature of analyzing tank structures under blast load, the paper addresses controversial aspects discussed in the literature and presents a suitable analysis concept for a deflagration blast scenario for cylindrical tanks. The results provide insights into the expected structural behavior of the tank under high-pressure and long-duration overpressure. The main finding is that the calculation method developed in this study demonstrates the feasibility of utilizing steel tanks in scenarios involving long-duration and high-pressure blast loads. Furthermore, the paper provides recommendations to guide future studies in this area. The findings have implications for the design and construction of tanks in critical infrastructure and offer valuable insights for engineers and researchers in this field, improving safety standards and ensuring adaptability to future utilization concepts.