Life Safety Risk Research Articles

Consideration of life safety risk equity principles in the assignment of design flood probability

ABSTRACT When designing hazardous infrastructure a life safety assessment process can be applied that considers three tests; 1 an individual risk equity test; 2 a societal intolerance test; and 3 a ‘legal’ test as to whether risks are reduced to be ‘so far as is reasonably practicable’ (SFAIRP) or ‘as low as reasonably practicable’ (ALARP). This approach, which is embedded in many workplace health and safety regulatory jurisdictions and safety standards for infrastructure including dams, nuclear facilities and industrial facilities, has clear justification, can be rigorously tested, and is defensible. While evidence to suggest a strong societal intolerance to floods is limited (i.e. there does not appear to be a disproportionate reaction to life loss from flood events compared to, for example, dam failure) there is a clear connection between flood risk and life safety equity principles. An individual life safety risk equity test, considering a person’s right to certain levels of protection in our society, compares flood risk with that of the background life safety risks from all hazards that exist in the Australian community. Based on age and gender distributed census data and typical annual exceedance probabilities assigned for flood management, there may be circumstances where flooding is the leading fatality risk for particular individuals living on a floodplain. Other considerations include ownership of flood risk (the floodplain manager or the individual), the distinction between voluntary and involuntary risk taking (noting that many road fatalities occur during flood events), the ratio between flood exposure and fatality (including flood hazard) and any legal and ethical obligations relating to public safety and a standard of care.

Effects of Wars on Merchant Seafarers: Study on Experiences and Concerns in the Russia-Ukraine War

Merchant seafarers, the key workers of the global economy as stated by the International Maritime Organization, are becoming targets of armed attacks, even if they have nothing to do with weapons. Several ships have been assaulted, and their crew members have suffered in the ongoing Russian-Ukrainian war in the Black Sea. There is a developing area of interest in the mental well-being of seafarers; however, current studies mostly focus on the effects of piracy. This research aims to offer a novel model that may identify the effects of war on seafarers, and the importance of each contributing factor that may potentially induce a concern in merchant seafarers. According to the results, financial pressures dominated over other sources of concern, which include life safety risks. The findings of this study may offer valuable data to policymakers for developing strategies with respect to the protection and well-being of seafarers.

A spectral assessment for instant preliminary evaluation of structures after seismic events

This article introduces a simple, efficient spectral-based approach for rapid preliminary seismic assessment of earthquake-affected structures. Performance is validated using data from three highly earthquake-affected structures in New Zealand, where visual inspection with subjective outcomes missed damage, resulting in inaccurate and delayed decisions with significant social and economic losses. The three structures considered include (1) the instrumented Bank of New Zealand (BNZ) building; (2) the un-instrumented Queensgate Mall (QM) Complex; and (3) the un-instrumented Canterbury Television (CTV) building. This study uses these cases to highlight the importance of structural health monitoring (SHM) instrumentation and reliable quantified post-earthquake assessment methods in earthquake-prone areas, where each damaging earthquake and subsequent further-damaging aftershocks demand continuous monitoring to continuously assess damage and life safety risk. The simple, low-cost spectral analyses in this study clearly show the existence of damage and deterioration not fully discovered with standard visual inspection methods. This outcome highlights the importance of sensor networks and SHM instrumentation so quantitative, post-event analysis can rapidly augment and target further, more subjective visual inspection results.

Methodology to incorporate seismic damage and debris to evaluate strategies to reduce life safety risk for multi-hazard earthquake and tsunami

This paper presents a methodology to evaluate life safety risk of coastal communities vulnerable to seismic and tsunami hazards. The work explicitly incorporates two important aspects in tsunami evacuation modeling: (1) the effect of earthquake-induced damage to buildings on building egress time, (2) the effect of earthquake-induced debris on horizontal evacuation time. The city of Seaside, Oregon, is selected as a testbed community. The hazard is based on a megathrust earthquake and tsunami from the Cascadia Subduction Zone that was defined in a previous study. The built environment consists of buildings and the transportation network for the city. Fragility analysis is used to estimate the seismic damage to buildings and resulting debris that covers portions of the road network. The horizontal evacuation time is determined based on the shortest path to shelters, including the increased travel time due to the earthquake-generated debris. The effects of different mitigation strategies are quantified. Results indicate the fatality and life safety risk of a near-field tsunami increases by 4.2–8.3 times when the effects of building egress and earthquake-induced debris are considered. The choice of population layer affects the life safety risk and thus the maximum risk is obtained when daytime populations are considered. Use of mitigation strategies result in a significant decrease in the number of fatalities. For hazards with recurrence intervals larger than 500- to 1000-years, the seismic retrofit is comparable to vertical evacuation and an effective strategy in reducing fatalities and associated risks. Implementing all mitigation strategies reduces the life safety risk by 90%.

How Do COVID-19 Risk, Life-Safety Risk, Job Insecurity, and Work-Family Conflict Affect Miner Performance? Health-Anxiety and Job-Anxiety Perspectives.

The coronavirus pandemic (COVID-19) has created challenging working conditions in coal-production activities. In addition to the massive loss of resources for miners, it has had a devastating impact on these individuals' mental health. Based on the conservation of resources (COR) theory and a resource-loss perspective, this study examined the impact of COVID-19 risk, life-safety risk, perceived job insecurity, and work-family conflict on miners' job performance. Moreover, this study investigated the mediating role of job anxiety (JA) and health anxiety (HA). The study data were collected through online structured questionnaires disseminated to 629 employees working in a coal mine in China. The data analysis and hypothesis generation were conducted using the structural equation modeling (partial least squares) method. The results demonstrated that the perception of COVID-19 risk, life-safety risk, job insecurity, and work-family conflict negatively and significantly impacted miners' job performance. In addition, JA and HA negatively mediated the relationships between the perception of COVID-19 risk, life-safety risk, perceived job insecurity, work-family conflict, and job performance. The findings of this study can give coal-mining companies and their staff useful insights into how to minimize the pandemic's effects on their operations.

UNet segmentation network of COVID-19 CT images with multi-scale attention.

In recent years, the global outbreak of COVID-19 has posed an extremely serious life-safety risk to humans, and in order to maximize the diagnostic efficiency of physicians, it is extremely valuable to investigate the methods of lesion segmentation in images of COVID-19. Aiming at the problems of existing deep learning models, such as low segmentation accuracy, poor model generalization performance, large model parameters and difficult deployment, we propose an UNet segmentation network integrating multi-scale attention for COVID-19 CT images. Specifically, the UNet network model is utilized as the base network, and the structure of multi-scale convolutional attention is proposed in the encoder stage to enhance the network's ability to capture multi-scale information. Second, a local channel attention module is proposed to extract spatial information by modeling local relationships to generate channel domain weights, to supplement detailed information about the target region to reduce information redundancy and to enhance important information. Moreover, the network model encoder segment uses the Meta-ACON activation function to avoid the overfitting phenomenon of the model and to improve the model's representational ability. A large number of experimental results on publicly available mixed data sets show that compared with the current mainstream image segmentation algorithms, the pro-posed method can more effectively improve the accuracy and generalization performance of COVID-19 lesions segmentation and provide help for medical diagnosis and analysis.

Dam and Levee Safety Risk during Remedial Construction

Abstract Structural modifications to dams and levees can create life safety risks during the construction period. It is important for all parties involved to understand the potential risk, evaluate methods to mitigate risk, and consider the risk when making decisions. Most importantly, it is critical to always strive to “do no harm” and prevent activities that could potentially increase risk. This case history will provide examples of conditions that can lead to increased risk during construction including excavations that lower the crest of a dam or levee, excavations at the toe of an embankment, rapid embankment construction, blocked bypass tunnels, spillway modifications, excavations for outlet culverts, and damage from grouting. A key component of many construction projects is a temporary cofferdam to protect the work area from flooding. Cofferdams have a high potential to create risk during construction. An important step to help prevent increasing risk during construction is to have multiple constructability reviews during the development of the project design. If the potential for construction risk is properly identified, the risk can often be mitigated or reduced. Decision-maker involvement is necessary to assure risks are understood and proper decisions can be made. Several case histories are presented to demonstrate how risks during remedial construction are evaluated and incorporated into decision-making.

Interface engineering with porous graphene as deposition regulator of stable Zn metal anode for long-life Zn-ion capacitor

The zinc (Zn) dendrite accumulation leads to poor Coulombic efficiency, continuously failing life and severe safety risks, which seriously impede the commercial application of Zn ion capacitors (ZICs). Herein, an interface engineering is proposed for the Zn metal anode to restrain the dendrite by using porous flame reduced graphene oxide (FRGO) as the ex-situ protective and regulated layer to induce the Zn crystal growth and restricts the side reactions. The FRGO possesses extensive nanoscale pores and zincophilic oxygen-containing functional groups, which can absorb Zn2+ and nucleate preferentially on the surface of FRGO, then induce the growth of Zn parallel to the graphene sheet by matching the basal (002) plane of metallic Zn to minimize lattice strain. As a result, it eliminates the tip effect and achieves the deposited Zn with a uniform and flat surface. Therefore, The FRGO on the Zn (FRGO@Zn) anode significantly reduces the nucleation overpotential and improves the cycling life during the plating/stripping process. Notably, FRGO@Zn based ZIC can achieve 91.0% capacity retention after more than 20,000 cycles at 5 A g−1, and its capacity and maximum energy density are 150.6 mAh g−1 and 118.8 Wh kg−1, respectively. This interface engineering of FRGO for the Zn metal anode has excellent application potential and theoretical guidance in the ZICs field.

Seismic repair and retrofit prioritization framework

The 2010–2011 Canterbury earthquake sequence caused significant damage to the Canterbury District Health Board (CDHB) building stock. The extent of damage, post-earthquake changes to the seismic code, new legislation around earthquake-prone buildings, and ongoing changes to clinical service requirements created a challenging decision-making environment for capital works repair and retrofit. In this article, we present a framework designed to assess the seismic resilience of buildings from a holistic perspective and to determine appropriate levels of seismic retrofit. The framework design ensures that decisions are driven by building criticality in the context of a healthcare system. It helps users to balance life safety risk and the demands of delivering critical clinical services day to day: resulting in safe facilities that provide effective health services under a range of future conditions. Pilot application of the framework enabled the reprioritization of significant capital toward buildings that provide the most life safety and health service resilience benefits in the long term. The process and resulting framework from this project is applicable to a wider range of building owners navigating seismic retrofit decision-making and the emerging movement toward functional recovery–based building regulation.

What drives landslide risk? Disaggregating risk analyses, an example from the Franz Josef Glacier and Fox Glacier valleys, New Zealand

Abstract. We present a quantitative risk analysis (QRA) case study from the Kā Roimata o Hine Hukatere / Franz Josef Glacier and Te Moeka o Tuawe / Fox Glacier valleys, on the west coast of the South Island, Aotearoa / New Zealand. The glacier valleys are important tourist destinations that are subject to landslide hazards. Both valleys contain actively retreating glaciers; experience high rainfall; and are proximal to the Alpine Fault, which is a major source of seismic hazard on the west coast. We considered the life safety risk from rockfalls, soil/rock avalanches, and flows that either are seismically triggered or occur aseismically. To determine the range in risk values and dominant contributing variables to the risk, we modelled nine different risk scenarios where we incrementally changed the variables used in the risk model to account for the underlying uncertainty. The scenarios represent our central estimate of the risk, e.g. neither optimistic nor conservative, through to our upper estimate of the risk. We include in these estimates the impact time-variable factors, such as a recently reactivated landslide, have had on locally increasing risk and the time-elapsed since the last major earthquake on the nearby Alpine Fault. We disaggregated our risk results to determine the dominant drivers in landslide risk, which highlighted the importance of considering dynamic time-variable risk scenarios and the changing contributions to risk from aseismic versus seismic landslides. A detailed understanding of the drivers of landslide risk in each valley is important to determine the most efficient and appropriate risk management decisions.

Regulating lithium metal interface using seed-coating layer for high-power batteries

• Li metal interface is engineered using seed-coating of N-rich graphene quantum dots. • A regulated SEI on Li metal assures ultra-stable cyclability even at 30 mA cm −2 . • Li is uniformly guided beneath seed-coating layer with dendrite-free plating. • Robust and stable composite SEI mitigates continuous consumption of electrolyte. Li metal has received heightened attention as an anode material for next-generation batteries due to its extremely large theoretical specific capacity. Employing Li metal anodes, however, involves considerable challenges, such as the formation of Li dendrites, depletion of electrolyte, and breakage of the solid electrolyte interphase layer. These issues potentially limit cell cycle life and pose safety risks. While recent studies demonstrated promising results, facile and scalable methods for achieving high power Li metal batteries are still elusive. Herein, the interface of lithium metal is regulated by seed-coating of nitrogen-rich graphene quantum dots (N-GQDs), which facilitates the formation of a robust and stable solid electrolyte interface layer. The highly lithiophilic nature of N-GQDs enables uniform lithium ionic flux even at high current densities and promotes dendrite-free lithium plating morphology with a low nucleation overpotential of 3 mV (45 mV for bare copper). Such a robust layer enables highly reversible Li plating/stripping in symmetric cell configuration for over 8,000 h at a current density of 30 mA cm −2 . Furthermore, the lithium iron phosphate-coupled full cell performs stable cycling for over 500 cycles. The introduction of seed layers represents a viable strategy for achieving high-power Li metal batteries by regulating the highly reactive lithium metal surface.

Towards understanding, estimating and mitigating higher-mode effects for more resilient tall buildings

Rapid urbanization has resulted in increased demand for tall buildings in many large and medium-sized cities around the world. Current code-based standards for seismic design are primarily aimed at minimizing life-safety risks under major earthquakes. While reinforced concrete (RC) high-rise buildings designed following current code requirements are expected to achieve collapse-prevention, the contribution of higher modes of vibrations to the dynamic response of these structures can produce seismic demands significantly larger than those obtained from prescriptive code-based procedures, causing unexpectedly higher structural and non-structural damage to these buildings. These imply considerable costs associated with the loss of residences and business operations as well as the post-earthquake recovery of cities. This paper presents a concise review of the current state-of-the-art and state of research pertaining to the understanding, estimation and mitigation of higher-mode effects on the seismic response of tall and slender RC structures. The paper is organized into four main foci: (1) analytical studies on understanding and quantifying higher-mode effects, (2) available experimental work on this topic, (3) advances in code practices in accounting for higher-mode effects in seismic design of RC tall buildings, and (4) recent developments in innovative systems intended to mitigate higher-mode effects in RC tall buildings. The paper concludes by briefly summarizing future challenges facing the construction of earthquake-resilient RC tall buildings that are essential in building resilient cities of the future.

Semi-quantitative seismic risk screening tool for existing buildings in Canada

The National Research Council of Canada (NRC) recently developed a semi-quantitative seismic risk screening tool (SQST) for existing buildings in Canada. The SQST is intended to supersede the Manual for Screening of Buildings for Seismic Investigation developed by the NRC in the early 1990s. The SQST consists of three key components: (i) a structural scoring system that quantitatively assesses the structural seismic risk based on probability of collapse; (ii) a nonstructural component scoring system that qualitatively assesses the seismic risk of nonstructural components based on seismic demand; and (iii) a ranking procedure that prioritizes potentially hazardous buildings for seismic evaluations and possible upgrading. The intent of the SQST is to inexpensively identify and exempt buildings with acceptable life safety risk and optimize the allocation of resources to assess the seismic risks to portfolios of buildings. Seismic screening with the SQST can be completed with either paper-based screening forms or a web-based application. The applicability of the SQST was demonstrated with a pilot study for 33 existing buildings across Canada.

Toward functional recovery performance in the seismic design of modern tall buildings

Current building code requirements for seismic design are primarily intended to minimize life-safety risks due to structural damage under extreme earthquakes. While tall buildings designed under current standards are expected to achieve the life-safety goal, this study estimates that they may require up to 7.5 months of repair to return to functionality after a design-level earthquake (roughly equivalent to ground motion shaking with a 10% probability of exceedance in 50 years), and over 1 year after a risk-targeted maximum considered earthquake (roughly equivalent to ground motion shaking with a 2%–4% chance of exceedance in 50 years). These long downtimes, which correspond to median predictions, far exceed recovery goals for major employers and other recovery-critical uses and can have disproportionately harmful effects on businesses and residents. To address such extensive downtime risks, we evaluate the impact of recovery-based design guidelines for reducing recovery times through (1) more stringent drift limits under expected ground motions and (2) measures to mitigate externalities that impede recovery. The results suggest that by combining these strategies, expected recovery times following a design-level earthquake can be reduced to roughly 1 month, and to 2 months following a risk-targeted maximum considered earthquake. These findings are illustrated for an archetype 42-story reinforced concrete shear wall residential building and a 40-story steel buckling-restrained braced frame office building in San Francisco, CA.

Experimental investigation into the seismic fragility of a commercial glazing system

Good seismic performance of glazing systems is essential to maintaining building functionality and limiting repair costs in a post-earthquake scenario. This paper reports on experimental research into the seismic performance of a standard commercial glazing system used in New Zealand. The focus of the research is to provide information not only on the life-safety performance of glazing but also on the serviceability of glazing systems, considering post-earthquake weather-tightness. This paper first describes the experimental testing set-up developed at the University of Canterbury to achieve this, then details the damage observed and finally, fragility functions for different damage states are reported. Leakage of the glazing is seen to initiate at a median storey drift demand of only 0.35%, whereas glass breakage did not occur until a median drift storey demand of 5.0%. The results obtained from this research demonstrate that the life-safety risk posed by modern commercial glazing in earthquakes will typically be low but the serviceability performance, and in particular weather-tightness post-earthquake, should be improved.

Explicit modelling of collapse for Dutch unreinforced masonry building typology fragility functions

The development of seismic fragility functions for buildings generally relies on simplified modelling methods and the use of indirect engineering demand parameters (EDPs) for the determination of collapse or other damage states. The collapse response of real buildings, particularly those that have not been specifically designed for seismic resistance, can often be driven by local failures that may not be captured in simplified models. Furthermore, the use of EDP thresholds to indicate damage states may not be consistent with multiple possible failure modes, which may be triggered by different characteristics of the ground shaking or variations in model parameters. This paper demonstrates the use of non-linear finite element models including explicit progressive collapse simulation for the development of fragility functions. It presents an overview of the method developed and its application to an unreinforced masonry (URM) building typology in the Groningen region of the Netherlands, where induced seismicity risk is currently being evaluated. Multiple index buildings were selected to represent the variations in geometry, material properties, and connection types found within the typology. For each index building, Latin Hypercube sampling was used to generate batches of several hundred realisations of an LS-DYNA time-history analysis, each selecting from a set of 100 hazard-consistent ground motions, and varying material properties and other uncertain variables according to pre-assigned probability distributions. Automation was used in model generation, running analyses and in post-processing to allow the required computation with minimal analyst intervention. The main output from each analysis was a normalised debris cover estimate, which describes the extent of damage observed in the model and is correlated with life safety risk. Regression analyses were carried out directly on threshold levels of debris cover identified building collapse. Fragility functions were developed for the URM terraced house typology by combining results from the individual index buildings together.

Semi-quantitative classification of consequences of failure for seismic risk management of existing buildings

This paper presents a uniform and consistent semi-quantitative classification of consequences of failure of buildings as part of a multi-level seismic risk management framework for existing buildings to help building owners make risk-informed decisions for the seismic evaluation and retrofit of existing buildings to minimise the life safety risk. The management framework consists of three levels of risk assessment, namely: (i) Level 1: Preliminary seismic screening; (ii) Level 2: Semi-quantitative seismic risk screening; and (iii) Level 3: Quantitative seismic evaluation. The proposed classification consists in general of three classes, namely: (i) Consequence Class – Low (CC-L), (ii) Consequence Class – Medium (CC-M); and (iii) Consequence Class – High (CC-H). These consequence classes are based on semi-quantitative criteria, including building occupancy, number of people at risk, building area, number of storeys, and mobility and ability to escape. The proposed classification can be used to refine the building importance classification in many codes, standards and guides to yield more uniform classification of consequences of failure that can be integrated with the seismic risk management framework to determine more uniform risks of failure. An example illustrating the application of the proposed classification is provided for the case of office buildings.

Application of Blockchain and Internet of Things to Ensure Tamper-Proof Data Availability for Food Safety

Food supply chain plays a vital role in human health and food prices. Food supply chain inefficiencies in terms of unfair competition and lack of regulations directly affect the quality of human life and increase food safety risks. This work merges Hyperledger Fabric, an enterprise-ready blockchain platform with existing conventional infrastructure, to trace a food package from farm to fork using an identity unique for each food package while keeping it uncomplicated. It keeps the records of business transactions that are secured and accessible to stakeholders according to the agreed set of policies and rules without involving any centralized authority. This paper focuses on exploring and building an uncomplicated, low-cost solution to quickly link the existing food industry at different geographical locations in a chain to track and trace the food in the market.

Application of Blockchain and Internet of Things to Ensure Tamper-Proof Data Availability for Food Safety

The food supply chain plays a vital role in human health and food prices. Food supply chain inefficiencies in terms of unfair competition and lack of regulations directly affect the quality of human life and increase food safety risks. This work merges Hyperledger Fabric, an enterprise-ready blockchain platform with existing conventional infrastructure, to trace a food package from farm to fork using an identity unique for each food package while keeping it uncomplicated. It keeps the records of business transactions that are secured and accessible to stakeholders according to the agreed set of policies and rules without involving any centralized authority. This paper focuses on exploring and building an uncomplicated, low-cost solution to quickly link the existing food industry at different geographical locations in a chain to track and trace the food in the market.

Risk-Informed Requirements for Design and Assessment of Structures Under Temporary Use.

The relatively high failure rates, with important consequences in many cases, suggest that the implicitly acceptable risk levels corresponding to temporary civil engineering structures and activities might exceed the bounds of normally acceptable levels associated with different societal activities. Among other reasons, this may be attributed to the lack of a rational approach for the assessment of risks associated with the different technologies supporting these activities in general, and for structures in particular. There is a need for establishing appropriate target reliability levels for structures under temporary use taking into account specific circumstances such as reduced risk exposure times. This issue is being addressed in this article. Acceptance criteria for building-structure-related risks to persons obtained in prior studies are adapted to the special circumstances of nonpermanent risk exposure. Thereby, the general principle followed is to maintain the same risk levels per time unit as for permanently occupied buildings. The adaptation is based on the statistical annual fatality rate, a life safety risk metric that allows for a consistent comparison of risks across different societal activities and technologies. It is shown that the target reliability indices taking account of the temporary use of buildings might be significantly higher than the values suggested for permanently used structures.