• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.801-810
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• 2013

The main purpose of this study is to reframe sustainability or sustainable development concept in the field of planning in consideration of climate change and natural hazards. The new concept is expected to provide a theoretical foundation for upcoming hazard mitigation measures addressing climate change. The first and main argument of the new concept is that environmental protection should be inclusive enough to address urban (or community) security from current natural hazards. The second is that the balance between structural and nonstructural mitigation measures is critical to cope more effectively with extreme natural hazards in the era of climate change and also with conflicts driven by three goals of sustainability--environmental protection, economic development, and social justice. The following studies, based on this new concept of sustainablity, are expected (1) to address new participation methods for the conflict resolution, (2) to explore detailed and substantive planning strategies and creative technical and institutional solutions for environmental protection, natural hazard mitigation, and conflict resolution. Two of APFM(the Associated Programme on Flood Management)'s three natural hazard risk criteria, Exposure and Vulnerability, may guide the exploration.

• Earthquakes and Structures
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• v.24 no.4
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• pp.289-301
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• 2023

Developing a competent soil-bridge interaction model for the seismic analysis of piled foundation bridges is of utmost importance for investigating the seismic response and assessing fragility of these lifeline structures. To this end, ground motion histories are deemed necessary at various depths along the piles supporting the bridge. This may be effectively accomplished through time history analysis of a free-field standalone soil column extending from bedrock level to ground surface subjected to an input bedrock motion at its base. A one-dimensional site/ground response analysis (vide one-directional shear wave propagation through the soil column) is hence conducted in the present research accounting for the nonlinear hysteretic behavior of the soil stratum encompassing the bridge piled foundation. Two homogeneous soil profiles atop of bedrock have been considered for comparison purposes, namely, loose and dense sand. Analysis of the standalone soil column has been performed under a set of ten selected actual bedrock ground motions adopting a nonlinear time domain approach in an incremental dynamic analysis framework. Amplified retrieved PGA and maximum soil shear strains have been generally observed at various depths of the soil column when moving away from bedrock towards ground surface especially at large hazards associated with high (input) PGA values assigned at bedrock. This has been accompanied, however, by some attenuation of the amplified PGA values at shallower depths and at ground surface especially for the loose sand soil and particularly for cases with higher seismic hazards associated with large scaling factors of bedrock records.

• Structural Engineering and Mechanics
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• v.6 no.7
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• pp.773-784
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• 1998

To assess the collapse risk of transmission line structures subject to natural hazards, it is important to identify what hazard may cause the structural collapse. In Australia and many other countries, a large proportion of failures of transmission line structures are caused by severe thunderstorms. Because the wind loads generated by thunderstorms are not only random but time-variant as well, a time-dependent structural reliability approach for the risk assessment of transmission line structures is essential. However, a lack of appropriate stochastic models for thunderstorm winds usually makes this kind of analysis impossible. The intention of the paper is to propose a stochastic model that could realistically and accurately simulate wind loading due to severe thunderstorms. With the proposed thunderstorm model, the collapse risk of transmission line structures under severe thunderstorms is assessed numerically based on the computed failure probability of the structure.

• Wind and Structures
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• v.34 no.3
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• pp.313-319
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• 2022

The resiliency of electricity transmission and distribution lines towards natural and man-made hazards is critical to the operation of cities and businesses. The extension of these lines throughout the country increases their risk of extreme loading conditions. This paper investigates a unique extreme loading condition of a 100-year old distribution line segment that passes across a river and got entangled with a boom of a ship. The study adopts the Applied Elements Method (AEM) for simulating 54 cases of the highly deformable structural behaviour of the tower. The most significant effects on the tower's structural integrity were found to occur when applying the load with components in all three of the cartesian directions (i.e., X, Y and Z) with the full capacities of the four cables. The studied extreme loading condition was determined to be within the tower's structural capacity, attributed to the shear failure of the anchor bolts, which acted as a sacrificing element that fails to protect the transfer of tensioning load to the supporting tower.

• Structural Engineering and Mechanics
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• v.75 no.3
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• pp.401-414
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• 2020

Unlike the existing truss models for shear and torsion analysis, in this study, the torsional capacities of reinforced concrete (RC) members were estimated by introducing multi-potential capacity criteria that considered the aggregate interlock, concrete crushing, and spalling of concrete cover. The smeared truss model based on the fixed-angle theory was utilized to obtain the torsional behavior of reinforced concrete member, and the multi-potential capacity criteria were then applied to draw the capacity of the member. In addition, to avoid any iterative calculation in the existing torsional behavior model, a simple strength model was suggested that considers key variables, such as the effective thickness of torsional member, principal stress angle, and strain effect that reduces the resistance of concrete due to large longitudinal tensile strain. The proposed multi-potential capacity concept and the simple strength model were verified by comparing with test results collected from the literature. The study found that the multi-potential capacity could estimate in a rational manner not only the torsional strength but also the failure mode of RC members subjected to torsional moment, by reflecting the reinforcing index in both transverse and longitudinal directions, as well as the sectional and material properties of RC members.

• Health Policy and Management
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• v.9 no.1
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• pp.201-233
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• 1999

This study was carried out to find out the factors affecting on organizational commitment of hospital employees. For the purpose, the questionnaire-based research was done with 1280 hospital employees who were working in 2 university hospitals and 4 general hospitals located in Taegu City and Kyungpook Province from November 20, 1997 to December 22, 1997. The results of the study were summarized as follows. There were significant correlations among environmental variables, psychological variables, structural variables, vertical conflict, horizontal conflict, job satisfaction, and organizational commitment. By path analysis, variables such as pay, work involvement, work definiteness, met expectations, positive affectivity, distributive justice, job security, expectations before entering a hospital had significant positive effect on job satisfaction in order of size, while, vertical conflict, job opportunity, and horizontal conflict had significant positive effect on job satisfaction in order of size, while, vertical conflict, job opportunity, and horizontal conflict had signifecant negative effect in order of size. Variables such as job satisfaction, job security, work involvement, pay, vertical conflict, met expectations, distributive justice, positive affectivity, work unit control, job autonomy, and job routinization had significant positive direct effect on organizational commitment in order of size, while, job opportunity, job hazards and resource inadequacy had significant negative direct effects in order of size. It was found that the following variables, listed in order of size, had significant total effects on organizational commitment : job satisfaction, job security, job opportunity, work involvement, pay, met expectations, distributive justice, positive affectivity, job hazards, and work unit control. In considering abovc findings, it is recommended that programs for job satisfaction promotion, job security, decrease of intent to leave, work involvement promotion, adequate pay, met expectations, distributive justice, positive affectivity promotion, job hazards decrease, and work unit control grant should be implemented to increase organizational commitment.

• Structural Engineering and Mechanics
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• v.83 no.2
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• pp.179-193
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• 2022

The shear behaviour of reinforced concrete members has been studied over the past decades by various researchers, and it can be simulated by analysing shear panel elements which has been regarded as a basic element of reinforced concrete members subjected to in-plane biaxial stresses. Despite various experimental studies on shear panel element which have been conducted so far, there are still a lot of uncertainties related to what influencing factors govern the shear behaviour and affect failure mechanism in reinforced concrete members. To identify the uncertainties, a finite element analysis can be used, which enables to investigate the impact of specific variables such as the reinforcement ratio, the shear retention factor, and the material characteristics including aggregate interlock, tension stiffening, compressive softening, and shear behaviour at the crack surface. In this study, a non-linear probabilistic analysis was conducted on reinforced concrete panels using a finite element method optimized for reinforced concrete members and advanced sampling techniques so that probabilistic analysis can be performed effectively. Consequently, this study figures out what analysis methodology and input parameters have the most influence on shear behaviour of reinforced concrete panels.

• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.79-90
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• 2023

Existing reinforced concrete (RC) frame buildings have seismic vulnerabilities because of seismically deficient details. In particular, since cumulative damage caused by successive earthquakes causes serious damage, repair/retrofit rehabilitation studies for successive earthquakes are needed. This study investigates the repair effect of fiber-reinforced polymer jacketing system for the seismically-vulnerable building structures under successive earthquakes. The repair modeling method developed and validated from the previous study was implemented to the building models. Additionally, the main parameters of the FRP jacketing system were selected as the number of FRP layers associated with the confinement effects and the installation location. To define the repair effects of the FRP jacketing system with the main parameters, this study conducted nonlinear time-history analyses for the building structural models with the various repairing scenarios. Based on this investigation, the repair effects of the damaged building structures were significantly affected by the damage levels induced from the mainshocks regardless of the retrofit scenarios.

• Safety and Health at Work
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• v.13 no.3
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• pp.261-262
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• 2022

Globally, it is estimated that the number of people living outside of their country of origin reached 281 million in 2020. The primary drive of those migrants when migrating voluntarily is work to increase their income and provide for their families left behind in their home countries. Those who migrate immediately seek means of income to sustain themselves through a perilous process as currently evidenced in the war in Ukraine and not too long ago in Syria and Venezuela. Unfortunately, migrant workers are globally known to predominantly be working in "4-D jobs"- dirty, dangerous, and difficult and discriminatory; the fourth D was recently added to acknowledge the discriminatory aspect and other social determinants of health migrant workers face in their host country while exposed to precarious work. Consequently, migrant workers are at considerable risk of work-related illnesses and injury but their health needs are critically overlooked in research and policy. Recognizing the UN Universal Declaration of Human Rights "Everyone has the right to work, to free choice of employment, to just and favourable conditions of work and to protection against unemployment", we cannot consider any human life - thus, the life of migrant workers - as dispensable through a structural discriminatory process that undervalues their occupational safety and health, livelihood and the contribution these workers bring to their host countries. This was seen during the preparation for the upcoming world cup in Qatar where migrant workers were exposed to a multiplicity of serious hazards including deadly heat hazards.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.313-314
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• 2021

An old building over 30 years old continue to increase. Therefore, there will be more dismantling of old buildings in the future. Safety management of dismantling works is being strengthened. However, no consideration has been given to the effects of dismantling workers and their residents due to environmental hazards arising from the demolition process. Only spray and dust prevention measures are subject to inspection to minimize dust generation considering civil complaints around the site of dismantling work. In this paper, residential buildings, which account for the largest proportion of old buildings, were collected and identify total airborne bacteria and floating fungi among environmental hazards caused by non-structural dismantling work. Measurement results showed that workers during dismantling work are working in places with 4.8 times more total airborne bacteria than indoor air quality maintenance standards. Related research is needed for the health of dismantling workers.