• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.317-324
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• 2022

In this paper, an analysis method that considers the initial static displacement of structural members using an equivalent single-degree-of-freedom system is presented. Newmark's dynamic analysis algorithm was improved to consider the effect of the initial static displacements of structural members. The effect of the initial static displacement on the maximum response according to the assumed duration of the blast load and natural period of the member was investigated. The effects of positive and negative static displacements on the maximum dynamic responses of structural members subjected to a positively applied blast load were also studied. Modified response charts for the shock-type and pressure-type waves are presented so that static displacements can easily be considered. Using a design example, we demonstrate the significance of the modified response chart that considers the static displacement. Based on the results of this study, the maximum response of a the structural member can be easily obtained whilst considering its initial static displacement. The modified response chart presented in this study can be used for the structural design of plants and military facilities.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.23-33
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• 2020

As the scale of the economy expands, the number of cases of damage in enclosed spaces such as tunnels is increasing due to the accident of transportation vehicles of dangerous substances such as explosive flammable materials that have increased rapidly. In the case of road tunnels in particular, in the aspect of protection against the long-winding trend and the environment in the downtown area, the number of cases of passing through the downtown area increases, and securing the safety of structures against unexpected extreme disasters such as explosions during tunnel passage is very urgent. For this reason, developed countries are already conducting a review of internal bombardment, but there are almost no evaluation and countermeasures for explosion risk in Korea. Therefore, in this study, in order to evaluate the explosion safety of road tunnels, a boiling liquid explosive explosion (BLEVE), which is considered to have the greatest explosion load among vehicles driving on the road, is set as a reference explosion source, and the equivalent TNT explosion load is used for simulation of the explosion. A method of conversion was presented. In addition, by applying the derived explosion load, dynamic behavior simulation was performed by assuming various variables for the tunnel, and the explosion safety of the tunnel was analyzed.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.379-388
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• 2016

This study was aimed at identifying the actual state of workplace violence based on a survey conducted to 876 subway workers in Seoul and determining the relationship between workplace violence and mental health of workers. Data were collected via web site, using a structured questionnaire and for the analysis of the data, a multiple linear regression analysis was carried out by the statistical program SPSS 20.0. According to the results, the perpetrators of violence turned out to be "passengers" in all types of workplace violence: physical violence, verbal violence, sexual harassment and disregard for personality. As for the relationship between workplace violence and the mental health of the workers, statistically significant differences were shown between all the above mentioned workplace violence types and sub-areas of mental health. Also, as for the impact of workplace violence on the mental health of the workers, significant differences were found in physical violence, sexual harassment and disregard for personality, with 8.3 percent of explanatory power. Based on these findings, the study suggests the establishment and the application of customer interaction guidelines to protect subway workers from workplace violence along with specific measures customized for each work environment to prevent violence.