Hasil untuk "Disasters and engineering"

Mohammad Abdul Aziz, Sajedur Rahman, Avishek Ghosh et al.

Rapid urbanization in Bangladesh has led to an increasing demand for multi-storey buildings, necessitating robust structural design to resist lateral loads from both earthquakes and wind. This study analyzes the seismic and wind load performance of G+8 reinforced concrete (RC) building located in four different seismic zones of Bangladesh, using ETABS 2017 in compliance with the Bangladesh National Building Code (BNBC) 2020. The structure was evaluated under both seismic (EQX, EQY) and wind (WX, WY) loads. The structural analysis revealed that wind loads (WX and WY) consistently govern the lateral design for this structure, as evidenced by storey shear (peaking at 45 Kip at the base in Zone 4 and storey displacement (WX peaking at 8 in) and drift (WX peaking at 0.09 in) being substantially higher than seismic demands. Although base shear linearly increased almost threefold from Zone 1 (33.28 Kip) to Zone 4 (99.84 Kip) due to rising seismic zone coefficients, the wind forces dominate the serviceability checks. Maximum storey displacement and drift were concentrated in Zones 3 and 4, with the latter exhibiting the highest drift (0.065 in WX) and extreme torsional irregularity, peaking at 7.82 in WX. The analysis confirms that both seismic and wind effects significantly influence building performance, with seismic forces dominating in higher zones and wind-induced displacements being critical in specific directions. This underscores the importance of region-specific design considerations to ensure structural safety and serviceability in Bangladesh’s diverse seismic landscape.

Xu Han, Maria Koliou

There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes. Given the significant damage incurred by tornadoes upon communities, community resilience analyses for tornado-stricken communities have been gaining momentum. As the community resilience analysis aims to guide how to lay out effective hazard mitigation strategies to decrease damage and improve recovery, a comprehensive and accurate approach is necessary. Agent-based modeling, an analysis approach in which different types of agents are created with their properties and behavior clearly defined to simulate the processes of those agents in an external environment, is the most comprehensive and accurate approach so far to conducting community resilience simulations and investigating the decision-making for mitigation and recovery under natural hazards. In this paper, agent-based models (ABMs) are created to simulate the recovery process of a virtual testbed based on the real-world community in Joplin City, MO. The tornado path associated with the real-world tornado event that occurred in May 2011 is adopted in the tornado hazard modeling for the Joplin testbed. In addition, agent-based models are created for another virtual community in the Midwest United States named Centerville using an assumed tornado scenario of the same EF-scale as that in Joplin. The effects of hazard mitigation strategies on the two communities are also explored. A comparison between the analysis results of these two testbeds can indicate the influence of the characteristics of a tornado-prone community on the resilience of the community as well as on the effects of hazard mitigation strategies. It is observed that a community's level of development significantly impacts the tornado resilience. In addition, the effects of a specific type of hazard mitigation strategy on the recovery process are contingent upon testbed characteristics.

Guo-chen Hao, Ke-Bin Shi, Ke-wu Han

The construction of simple reservoirs in arid regions helps meet the water demands for agricultural irrigation, industry, and domestic use, while also alleviating local water shortages and related issues. However, environmental concerns associated with reservoir development are becoming more evident. For instance, the stored water is gradually becoming saline. Studies suggest that reducing water evaporation over extended periods can effectively lower the salt concentration in the water. Currently, there is limited research on salt migration in reservoir water when covered with anti-evaporation materials. Given the potential impact of these materials on the water environment and hydrodynamic conditions, this study seeks to examine the spatiotemporal distribution patterns of reservoir mineralization under such covering. To this end, laboratory and field experiments were conducted to analyze the impact of covering the water surface with floating high-density polyethylene spheres to reduce evaporation and its effect on water salinity. These experiments included monitoring water temperature, dissolved oxygen, pH, sediment resuspension, and water conductivity, as well as calculating the contribution of sediment release and evapotranspiration to the increase in salinity concentration within the water column. This study investigates the role of floating high-density polyethylene (HDPE) spheres in reducing reservoir evaporation and mitigating water salinity. Laboratory and field experiments assessed the effects of different coverage levels (0 %-74.98 %) on evaporation rates, sediment resuspension, and water chemistry. The findings indicate that covering 74.98 % of the reservoir surface led to a 28.97 % reduction in salinity (p < 0.05) over one irrigation cycle. Evaporation inhibition varied from 13.56 % to 60.19 %, depending on coverage. However, floating spheres exhibited reduced effectiveness at high wind speeds (>10.7 m/s), highlighting the need for additional containment strategies. Future research should explore long-term durability, ecological impact, and cost-effectiveness of large-scale deployment.

Helena Maria Simão, Alfeu Sá Marques, Nuno Eduardo Simões et al.

A vida sem água é impossível. Assim, a necessidade de origens de água adequadas, sistemas de abastecimento de água, controlo de cheias e reservas de água sempre levou à necessidade de desenvolver o planeamento dos recursos hídricos. As alterações climáticas, hoje um facto cientificamente demonstrado, implicarão agravamento de situações extremas e de eventos de seca e precipitação intensa, evidenciam a urgência de fortalecer a relação entre o planeamento urbano e a gestão de recursos hídricos, apostando em cidades mais sustentáveis e mais resilientes com mudanças na política de ocupação do solo, privilegiando soluções técnicas diferenciadas, preservando áreas de inundação ainda existentes, complementadas com intervenções para retenção na origem. No âmbito do planeamento urbano e dos recursos hídricos, neste artigo, identificam-se e avaliam-se possíveis reservas de água de superfície do concelho da Guarda e são avaliadas as áreas inundadas pelo Rio Diz, dentro da cidade da Guarda.

CHAN Ding On, XIAO Hang, XIA Linyuan, LICHTI Derek D., LI Ming Ho, DU Guoming

Registrations based on the manual placement of spherical targets are still being employed by many professionals in the industry. However, the placement of those targets usually relies solely on personal experience without scientific evidence supported by numerical analysis. This paper presents a comprehensive investigation, based on Monte Carlo simulation, into determining the optimal number and positions for efficient target placement in typical scenes consisting of a pair of facades. It demonstrates new check-up statistical rules and geometrical constraints that can effectively extract and analyze massive simulations of unregistered point clouds and their corresponding registrations. More than $6\times 10^{7}$ sets of the registrations were simulated, whereas more than 100 registrations with real data were used to verify the results of simulation. The results indicated that using five spherical targets is the best choice for the registration of a large typical registration site consisting of two vertical facades and a ground, when there is only a box set of spherical targets available. As a result, the users can avoid placing extra targets to achieve insignificant improvements in registration accuracy. The results also suggest that the higher registration accuracy can be obtained when the ratio between the facade-to-target distance and target-to-scanner distance is approximately 3:2. Therefore, the targets should be placed closer to the scanner rather than in the middle between the facades and the scanner, contradicting to the traditional thought. Besides, the results reveal that the accuracy can be increased by setting the largest projected triangular area of the targets to be large.

Roman Schotten, Evelyn Mühlhofer, Georgios-Alexandros Chatzistefanou et al.

Natural hazards impact interdependent infrastructure networks that keep modern society functional. While a variety of modelling approaches are available to represent critical infrastructure networks (CINs) on different scales and analyse the impacts of natural hazards, a recurring challenge for all modelling approaches is the availability and accessibility of sufficiently high-quality input and validation data. The resulting data gaps often require modellers to assume specific technical parameters, functional relationships, and system behaviours. In other cases, expert knowledge from one sector is extrapolated to other sectoral structures or even cross-sectorally applied to fill data gaps. The uncertainties introduced by these assumptions and extrapolations and their influence on the quality of modelling outcomes are often poorly understood and difficult to capture, thereby eroding the reliability of these models to guide resilience enhancements. Additionally, ways of overcoming the data availability challenges in CIN modelling, with respect to each modelling purpose, remain an open question. To address these challenges, a generic modelling workflow is derived from existing modelling approaches to examine model definition and validations, as well as the six CIN modelling stages, including mapping of infrastructure assets, quantification of dependencies, assessment of natural hazard impacts, response &amp; recovery, quantification of CI services, and adaptation measures. The data requirements of each stage were systematically defined, and the literature on potential sources was reviewed to enhance data collection and raise awareness of potential pitfalls. The application of the derived workflow funnels into a framework to assess data availability challenges. This is shown through three case studies, taking into account their different modelling purposes: hazard hotspot assessments, hazard risk management, and sectoral adaptation. Based on the three model purpose types provided, a framework is suggested to explore the implications of data scarcity for certain data types, as well as their reasons and consequences for CIN model reliability. Finally, a discussion on overcoming the challenges of data scarcity is presented.

YUAN Dong, XIAO Kun

Objective  With the relocation of major national strategic plans to western China, railway construction has gradually focused on the complex and dangerous mountainous regions of Yunnan, Sichuan, and Xizang Provinces, where the proportion of tunnels along the railway is very high. When a tunnel passes through a water-rich fault fracture zone, the rock mass in front of the palm face is prone to hydraulic fracturing and damage under high osmotic pressure, leading to disasters such as rock collapse and water inrush.   Methods  The wing crack model is introduced to fully account for the initiation and propagation of secondary wing cracks in water-saturated fractures, as well as the impact of excavation disturbances. The effective tensile stress and rock bridge size between intermittent fractures in the rock are revised. The tensile-shear failure mechanism of the water-insulating rock mass in front of the tunnel face is analyzed, and the critical water pressure for hydraulic fracturing of the water-insulating rock mass is derived. The minimum safety thickness for the tunnel face against water inrush in the proximity of a fault fracture zone is proposed.   Results  The theoretical formulas indicate that the anti-splitting thickness of the water-insulating rock mass is related to factors such as tunnel section size, fault water pressure, excavation disturbance, in-situ stress, rock mass strength, crack size, and fracture parameters. Through analysis of the sensitivity of the different influencing factors, it is found that the anti-splitting thickness of the rock mass increases with the increase of the tunnel section size, the fault water pressure, and the excavation disturbance factor, but decreases with the increase of the vertical tunnel stress and the rock mass strength. At the same time, the excavation disturbance damage has the most significant impact on the calculated anti-splitting thickness of the rock mass.   Conclusion  In practical engineering, there are certain empirical judgments and errors in obtaining excavation disturbance factors via rock integrity assessment and rock wave velocity testing. Therefore, this method requires accurate acquisition of the damage conditions of the rock mass in front of the tunnel face. Various assessment methods can be used for comparison and selection, and a conservative approach can be adopted by using a larger value for the excavation disturbance factor.   Significance  Finally, taking a tunnel in western Sichuan near the Yalahe fault as an example and considering the actual engineering disturbance and fault water pressure, the minimum safety thickness of the rock wall at the tunnel face is calculated to verify the engineering applicability of the proposed method. This research can effectively guide on-site risk prediction and plan formulation; it provides a theoretical basis for the prevention and control of water inrush in tunnels crossing water-rich fault fracture zones.

Sáhira Michele da Silva Celestino, Andréa Aparecida Zacharias, André Luiz Lopes de Faria et al.

A incidência dos desastres naturais no Brasil, sobretudo nas áreas urbanas, intensificado pelo processo de urbanização e industrialização, tem deixado em alerta toda a população devido aos riscos ambientais. Nos últimos dez anos, a população brasileira, em especial do estado de Minas Gerais, vem se destacando como um dos mais atingidos pelos desastres naturais associados a chuva. Compreendendo a escola como espaço de discussão e disseminação de conhecimentos, a Geografia é capaz de trazer a compreensão e respostas para os riscos ambientais enfrentados no lugar. Desse modo, com o intuito de promover discussões e reflexões na interface de três campos - Geografia, Riscos e Educação – o objetivo da pesquisa foi apontar caminhos para trabalhar o enfrentamento dos riscos ambientais em Cajuri/Minas Gerais/Brasil por meio do ensino de Geografia nas escolas locais e percepção dos riscos, a partir da perspectiva construcionista e pesquisa participante-colaborativa. A intervenção da educação geográfica nos processos do ensino e aprendizagem foi essencial para apontar caminhos estratégicos de mitigação do risco através da sistematização coletiva de um Atlas Municipal Escolar de Cajuri/MG, cujas informações sobre a geograficidade, a historicidade e os diferentes ambientes da paisagem urbana e rural, possibilitarão novos conhecimentos e percepção sobre o lugar, entendendo suas dinâmicas, interações e conflitos que potencializam os riscos ambientais.

Jeffrey M. Keisler, Emily M. Wells, Igor Linkov

Abstract This article develops a novel decision-oriented framework that strategically deconstructs systems resilience in a way that focuses on systems’ design, capabilities, and management. The framework helps evaluate and compare how system design choices impact system resilience. First, we propose a resilience score based on a piecewise linear approximation to a resilience curve. Using multicriteria decision analysis principles, we score system design alternatives in terms of system-specific capabilities. We estimate the relevance of these capabilities to resilience curve parameters associated with resilience phases. Finally, we interpret the derivatives of resilience with respect to the curve parameter values as the leverage of these parameters. Using multiple levels of weighted sums of the scores, we calculate the first order impact of system design choices first on a proxy for the generic resilience parameters and then on resilience, which allows situational characteristics to be incorporated in their natural terminology while mapping their impact on resilience with a traceable logic. We illustrate the approach by using existing materials to develop an example comparing engineered designs for minimizing post-wildfire flood impacts.

Hülya Keskin Çıtıroğlu, Deniz Arca

Climate refers to the average of meteorological events and weather conditions observed over a long period of time for a region. Many scientists have made different climate classifications. The main goal in these classifications is to determine the similarities of the investigated environments by identifying climate types. Determining climate characteristics and understanding climate boundaries contribute to the sustainability of resources in the region and aid in the preparation of land use plans. It is clear that assessment the boundaries of various climate types to ensure sustainability of regional resources and land use plans. In this study, it was aimed to determine climate boundaries in order to prevent climate-related problems. For this purpose, in this study, the creation of the climate boundary maps of Bartın province (Amasra, Kurucaşile, Merkez District and Ulus) was taken as a basis, based on the need to form a basis for planning. For this reason, the water balance of each district station was calculated using measurement data from four meteorological stations located in the districts of Bartın province for the last thirty years, utilizing the Thornthwaite climate classification method. Additionally, climate types were determined using the Thornthwaite, Trewartha, Erinç, De Martonne, Köppen, and Trewartha climate classification methods. Then, Geographic Information System (GIS)-based climate boundary maps were produced by applying the Kriging interpolation method to the data associated with the location.

Mohammad Amini, Longsheng Deng, Longsheng Deng et al.

The main difficulties in urban development, choosing a location, and creating preventative safety precautions are accurately characterizing and valuing subsurface soil information from a geotechnical and geological standpoint. This paper discusses how to define and build geotechnical subsoil soil zonation maps (SZMs) for the new Kabul city, Afghanistan, using traditional ArcGIS software assessing Kriging interpolation approaches. With the city’s expansion plans, including New Kabul City’s development, our research supports informed urban development strategies. Subsoil data from 2,13 locations across the city were collected from geotechnical studies, focusing on soil classification, Standard Penetration Test (SPT-N values), undrained shear strength, and consolidation characteristics up to 15 m depth. SPT-N and soil type were used to create SZMs, and other parameters were used to evaluate bearing capacity and settlement. The results revealed that SPT-N values divided the research region into three main sections: A (8–&gt;50), B (13–&gt;50), and C (14–&gt;50). The subsurface strata consist of low-plasticity clay (CL) and clayey sand (SC) underlain by highly plastic clay (CH) and silt (MH). Linear regression predicted SPT-N values with depth, showing a strong R2 of 0.95. This speeds up sub-soil stiffness and strength assessments during building project planning and feasibility studies. The shallow Kabul foundation has an allowable bearing capacity of over 100 kPa, making it suitable for lightly loaded buildings. Predicting SPT-N levels has an 85% correlation coefficient, while soil type has 94%. Accurate geotechnical data on the soil’s underlying layers will help characterize the site and identify future project risks.

M. A. Fulazzaky, A. Syafiuddin, K. Muda et al.

Ahmed E. El-Rayes, Mohamed O. Arnous, El-Arabi H. Shendi et al.

Abstract Background The Southern Suez Canal Province (SSCP) has recently encountered hydro-environmental hazards such as water logging and soil salinization, both of which impede the efficient land use planning. Purpose This study aims to assess the hydro-environmental threats to SSCP and identify the key factors that contribute to their occurrence. Previous research has demonstrated that the Gulf of Suez Rifting-related tectonic movements have a significant impact on the entire SSCP region. The influence of tectonic setting on the development of hydro-environmental dangers was not examined in almost any studies. Methods Remote sensing, GIS, hydrogeological, and geophysical techniques are used to identify and assess topographic, hydrogeological, and tectonic variables that affect hydro-environmental hazards in the SSCP. Results This study found that the distributions of water logging, saturated soil salinization, urban areas, and vegetation cover changed more dramatically between 1984 and 2015. The expansion of water logging area (+10.68 km2 rating +0.35 km2/y), saturated saline soil (+24.40 km2 rating +0.79 km2/y), and urbanized area (+58.43 km2 rating +1.89 km2/y) is strongly associated to the expansion of vegetation cover (+188.13 km2 at a rate of 6.07 km2/y). This could imply that growing agricultural expansion and urbanization are influencing the dominance of hydro-environmental hazards in SSCP. The distribution of water logging features identified on the land cover map corresponds closely to a buried horst structure dominating the middle part of the surveyed area. Conclusion The lowland water logging features of the SSCP provide support for the hypothesis that the buried horst structure that dominates the Miocene and pre-Miocene strata has an impact on the thickness and groundwater flow regime of the quaternary aquifer that lies above. The present study came to the conclusion that the shallow depth of groundwater, the vast expanse of newly cultivated lands, the impervious clay layer beneath the thin topsoil layer, and the low topography are the key factors influencing the development of water logging and soil salinization features in SSCP.

Yi Luo, Kun Xu, Junhong Huang et al.

Abstract In the development of deep underground engineering operations, the surrounding rock is prone to large deformation, rockbursting, and other major engineering disasters. Pressure-relief blasting can improve the stress field in a deep rock mass and prevent the occurrence of roadway collapse. Based on the excavation of the Sandaoshan Mine, ANSYS/LS-DYNA dynamic finite element software is used to simulate the damage and fracture area in the surrounding rock of the roadway under three types of pressure-relief blasting schemes. The strength of the rock mass in the damaged area is reduced, and then the ground stress balance calculation is conducted. The stability of the surrounding rock rock a deep roadway is compared and analysed from aspects of stress and energy and it is verified by theoretical calculation of impact energy factor. The research results show that the non-penetrating fracture zone formed by pressure-relief blasting will increase the stress concentration of the surrounding rock of the roadway, which is more unfavourable to engineering safety. When a reasonable blasting scheme is designed to form a penetrating fracture zone in the surrounding rock of roadway, the concentrated high ground stress in the surrounding rock can be transferred to the deeper part of the rock mass, thereby reducing the elastic strain energy, reducing the risk of a rockburst. Pressure-relief blasting increases the rock mass quality in the failure zone formed by excavation, and reduces the impact energy factor k. When k decreases below the energy threshold, it can prevent rockbursting and ensure the stability of the surrounding rock of the roadway.

Ananya Tiwari, L. Rodrigues, F. Lucy et al.

Climate change leads to an unequivocal rise in the intensity and frequency of natural disasters. This necessitates mainstreaming of climate adaptation strategies in the global movement on climate action. Ecosystem-Based Adaptation (EBA) has become popular as an effective means of climate adaptation, which can be resilient and flexible compared to hard engineering-based measures. However, ecosystem-based approaches in disaster risk reduction still remain under-researched despite their growing popularity. This study delves into the utility of EBA in the context of the living lab, using a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) based Systematic Literature Review. A living lab (LL) is a participatory tool invented to foster innovation through real-life testing environments, such as individual cities. This study focuses on European coastal regions, as these are both highly populated and vulnerable to climate change impacts such as sea-level rise, storms, flooding and erosion. This study identified multiple synergies between the EBA concepts, living lab and disaster-risk reduction and concludes that EBA schemes can be highly effective in the living lab set-up. It also demonstrates that increased stakeholder engagement and the consideration of socio-economic co-benefits as part of the EBA-LL model can lead to successful disaster risk reduction.

Zhen-hao Xu, P. Lin, H. Xing et al.

Xiukuo Sun, Xiao Li, B. Zheng et al.

Abstract Soil and rock mixture (SRM) is very common in engineering as a type of extremely heterogeneous and anisotropic geological material. SRM is easy to fracture and damage under external forces, which often causes geological disasters, such as landslide and debris flow. Therefore, study on the progressive fracturing of this material is very important for geological engineering. In this paper, uniaxial compression test with real-time computed tomography (CT) scanning was conducted on SRM samples (with rock percentage of 40%). The evolutions of visible fractures, invisible fractures in CT slices, average density and heterogeneity of the sample during loading process were all studied quantitatively. This research finds that invisible fractures occur soon once loading begins, gradually accumulate in elastic deformation stage, and finally form visible fractures in plastic deformation stage. Average density of the whole sample slightly declines, while heterogeneity greatly increases during the evolution of fracturing.

Hui Zhang, Zhizhang Wang, Zhenlong Song et al.

Jianwen Xu, K. Ota, M. Dong

After disasters, network communication is highly susceptible to disruption. In this case, we may need solutions without original architectures to meet the requirements of connectivity and communication. As a research hotspot, existing studies and practices in disaster management are often costly and may have to rely on differentiated strategies to deal with actual situations. In this paper, we choose UAVs as edge node carriers and LoRaWAN (Long Range Wide Area Networking) as a communication method in coping with mobile edge computing (MEC) for disaster management. Here we propose UAV-mounted MEC task management strategies to achieve emergency communication enabled by LoRaWAN. The system model includes two parts, air-to-ground and remote-to-air, in which we choose LoS/NLoS path loss model and log-distance to describe the connections. The experiment results show that our strategy can achieve low-cost, long-range MEC service, which can be quickly deployed in the affected area after disasters. We also choose path loss, SNR (signal-noise ratio), and channel capacity as performance metrics and prove that our solutions can increase the channel capacity while maintaining the same level of path loss and SNR.

Li-ping Li, Jie Hu, Shucai Li et al.