Dear Readers,
A themed issue on ‘Multi-Hazard Effects on Engineering Structures’ was called in 2022 in the Proceedings of the Institution of Civil Engineers (ICE) journal, Structures and Building with an aim of showcasing recent research developments in understanding multi-hazard effects on engineering structures. To understand (a) behaviour of structures subjected to multiple hazards, (b) performance of structural response modification devices under variety of dynamic loading, (c) developments in codes and standards addressing multi-hazard effects on engineering structures, (d) probabilistic multi-hazard structural engineering, (e) measurement and tracking of condition and performance over the lifespan of the structure, (f) lifecycle design, condition assessment, maintenance, and safety of structures particularly under multiple hazard conditions over their lifespan, a comprehensive compilation of research articles was proposed. It is gratifying to present herewith the extensive research developments on some chosen multi-hazard effects on engineering structures and broader impact thereof on resilient infrastructure development and society at large.
Multi-hazard analysis and design of structures are being researched across the world to study the multitude effects of natural, accidental/manmade hazards such as earthquakes, strong winds, snowfall, rainstorms, flood-induced scouring, tsunamis, landslides, blasts/explosions, fire outbreaks, to name a few (Roy and Matsagar, 2022, 2023). The physical and socio-economic losses caused due to such multiple hazards and significant impact on mankind are overwhelming, which calls upon serious attention of all stakeholders. Multiple hazards are broadly categorised as: concurrent, nonconcurrent, and cascading, which is governed by the conditional probability of their occurrences. Built infrastructure is influenced by these categories of scenario-based and site-specific hazards; for instance, inducing extensive damage in the structures, causing undue vibrations, and at times leading to catastrophic failures in buildings, bridges, etc. Variety of vibration control techniques for dynamic response mitigation of civil structures under multiple hazards are being developed, as reported by Zelleke et al., 2022 with an aim to addressing the structural distress caused. Base-isolated structures in particular are designed from conflicting demands and serviceability requirements from multiple hazards (e.g., earthquakes, windstorms, blast-induced ground motions), including capacity to ascertain continued services in case lifeline structures at operational level in performance-based design philosophy (Roy et al., 2021; Zelleke and Matsagar, 2024; Zelleke et al., 2024; Prakash and Jangid, 2024). Deterministic and probabilistic analysis and design approaches developed against multi-hazard scenarios are mandated to ensure structural safety (Roy and Matsagar, 2020) that are eventually required to be adopted in codes and standards (Roy and Matsagar, 2021).
In continuation of the multi-hazard resilient infrastructure development Devendiran and Banerjee (2024) have proposed a new framework for multi-hazard risk analysis of river-crossing bridges. It presents a risk-targeted multi-hazard design of bridges, which needs to be now considered on the basis of service-life performance. As highlighted earlier by Bhaskar et al., (2022) the in-situ effects, such as chloride-induced corrosion over the design life of the structures, are required to be accounted for at the design stage itself. Both bridges and buildings require scenario-based and site-specific designs and performance assessment, as conducted for cascading multi-hazard scenario of earthquake-induced landslide by Kulariya and Saha (2024) for three-dimensional step-back and split foundation hillside buildings. Apart from the natural causes affecting the structures, the accidental or manmade events such as explosions or blasts require separate attention and treatment, especially for strategically important infrastructure. Mandal and Goel (2024) have assessed explosion-induced landslide behaviour for a shallow buried mountain transit tunnel under such coupled loading scenario. For reinforced concrete (RC) structures, evaluating their blast, fire, and/or impact responses (Choudhary et al., 2024; Verma et al., 2024) and employing mitigation measures thereto are proposed using advanced engineered materials. For example, honeycomb sandwich structure has been studied to assess the damage attenuation and energy absorption capabilities under combined blast and fragment impact loading scenario by Shirbhate and Goel (2024); how about making its composite with RC structure?
In nutshell, this themed issue has adequately covered original research contributions on the analysis and design of structures subjected to multiple hazards, case studies on structural failures due to multiple loading scenarios emanating from natural or accidental/manmade hazards, current and future code practices on multi-hazard analysis and design of structures, and provoked related scientific and technological deliberations. Conventionally, structures are designed by considering material properties at the construction stage, while considering the loads and their combinations anticipated during the service-life of the structures. However, during the service-life, the structures may experience multiple hazards, which could be cascading (corelated) events or uncorrelated events. Ensuring adequate safety against such variety of hazard scenarios throughout the design life of the structures is essential, while duly considering material degradation as well as maintenance schedule over the period, which have aptly been addressed in this compilation.
