This study was conducted to determine the concentration of heavy metals and their characteristics in the bodies of 2,446 residents living near industrial areas from 2007 to 2015. The concentration of heavy metals showed diverse characteristics according to gender, food types consumed and period of residence. Especially, levels of cadmium and mercury were high in the urine samples of the group that had lived in the local area for a long time. In order to obtain more accurate results, it will be necessary to comprehensively study the influence and effects from such matters related to lifestyle, eating habits and levels of environmental pollutants.

Structural vibration induced by earthquake hazards is one of the most significant concerns in structure performance-based design. Structural hazards evoked from seismic events must be properly identified to make buildings resilient enough to withstand extreme earthquake loadings. To investigate the effects of combined earthquake-resistant systems, shear walls and five types of dampers are incorporated in nineteen structural models by altering their arrangements. All the building models were developed as per ACI 318-14 and ASCE 7-16. Seismic fragility curves were developed from the incremental dynamic analyses (IDA) performed by using seven sets of ground motions, and eventually, by following FEMA P695 provisions, the collapse margin ratio (CMR) was computed from the collapse curves. It is evident from the results that the seismic performance of the proposed combined shear wall-damper system is significantly better than the models equipped with shear walls only. The scrutinized dual seismic resisting system is expected to be applied practically to ensure a multi-level shield for tall structures in high seismic risk zones.

The recent increase in earthquake activities has highlighted the importance of seismic performance evaluation for civil infrastructures. In particular, the container crane essential to maintaining the national logistics system with port operation requires an exact evaluation of its seismic response. Thus, this study aims to assess the seismic vulnerability of container cranes considering their seismic characteristics. The seismic response of the container crane should account for the structural members’ yielding and buckling, as well as the crane wheel’s uplifting derailment in operation. The crane’s yielding and buckling limit states were defined using the stress of crane members based on the load and displacement curve obtained from nonlinear static analysis. The derailment limit state was based on the height of the rail, and nonlinear dynamic analysis was performed to obtain the seismic fragility curves considering defined limit states and seismic characteristics. The yield and derailment probabilities of the crane in the near-fault ground motion were approximately 1.5 to 4.7 and 2.8 to 6.8 times higher, respectively, than those in the far-fault ground motion.

In Korea, most nuclear power plants were designed based on the design response spectrum of Regulatory Guide 1.60 of the NRC. However, in the case of earthquakes occurring in the country, the characteristics of seismic motions in Korea and the design response spectrum differed. The seismic motion in Korea had a higher spectral acceleration in the high-frequency range compared to the design response spectrum. The seismic capacity may be reduced when evaluating the seismic performance of the equipment with high-frequency earthquakes compared with what is evaluated by the design response spectrum for the equipment with a high natural frequency. Therefore, EPRI proposed the inelastic energy absorption factor for the equipment anchorage. In this study, the seismic performance of welding anchorage was evaluated by considering domestic seismic characteristics and EPRI's inelastic energy absorption factor. In order to reflect the characteristics of domestic earthquakes, the uniform hazard response spectrum (UHRS) of Uljin was used. Moreover, the seismic performance of the equipment was evaluated with a design response spectrum of R.G.1.60 and a uniform hazard response spectrum (UHRS) as seismic inputs. As a result, it was confirmed that the seismic performance of the weld anchorage could be increased when the inelastic energy absorption factor is used. Also, a comparative analysis was performed on the seismic capacity of the anchorage of equipment by the welding and the extended bolt.

교량은 사용년한이 증가함에 따라 노후화로 인해 역학적인 성질과 구조적인 성능이 저하되고, 이로 인해서 강진 시에 내진성능이 저하된다. 교각과 교량받침에 대한 노후화를 몇 가지 단계로 정량화하여 해석모델에 반영하였고, 노후화된 교각과 교량받침에 대하 여 부재-수준의 지진취약도를 평가하였다. 교량 시스템의 파괴 메카니즘을 직렬시스템으로 가정하여, 부재-수준의 지진취약도 해석 결과로부터 시스템-수준의 지진취약도를 평가하는 방법을 제안하였다. 노후도에 취약한 부재인 교각과 교량받침에 대하여 5가지 정 량적인 노후도(0, 5, 10, 25, 40%)를 가정하여 부재-수준의 지진취약도를 평가하였고, 이 결과로부터 시스템-수준의 지진취약도 평가 를 수행하였다. 시스템-수준의 지진취약도는 교량받침 보다는 교각이 지배적인 영향을 줌을 알 수 있었다. 이는 보다 취약한 구조부재 의 지진취약도가 전체 교량시스템의 지진취약도에 지배적인 영향을 주는 것을 의미한다.

The 2017 Pohang earthquake caused severe damage to low-rise piloti buildings. The damage was caused mainly by column shear failure, and some core walls were as well. The damaged piloti buildings in Pohang City could be relieved if they were designed correctly according to the standards at that time. However, the post-earthquake investigation revealed design, construction, and permission problems. To solve the problems, the Piloti Building Structure Design Guidelines that include strict specifications were published in 2018. Separately, KDS 41 17 00, the seismic design standard for buildings, was enacted in 2019 and it included the guideline contents. Therefore, at least after the publication of the guidelines, piloti buildings, designed by the standard and guidelines, can be expected to possess better seismic performance than existing piloti buildings. To confirm this, the probability of exceedance for several damage state thresholds was estimated for existing and designed piloti buildings. As a result, the probability of damage of designed piloti buildings was very low compared to existing ones. Consequently, it was confirmed that the guideline and standard adequately supplement the structural fragility of existing piloti buildings.

본 논문에서는 국내 최초로 건축구조기준(KBC 2016)에 기반하여 확률적 영역에서 초과손상확률 형태와 평균손상확률 형태 의 강풍 취약도 평가 방법론을 개발하였다. 본 연구에서는 풍하중에 대한 3초 순간풍속의 영향을 고려할 수 있는 풍하중 산정식을 건 축구조기준을 기초로 유도하였다. 또한 풍하중과 관련된 문헌을 기초로 유도된 3초 순간풍속 기반의 풍하중 산정식에 적용할 수 있는 풍하중 산정계수의 통계치를 제시하였다. 본 연구에서는 초과손상확률 형태와 평균손상확률 형태의 강풍 취약도를 평가하기 위하여 몬테카를로 모사(Monte Carlo Simulation) 기법을 이용하여 해석적 확률 모델을 개발하였다. 제안한 강풍 취약도 평가 방법론의 신뢰 성은 저층 건축물 모형의 지붕 쉬딩 패널 시스템(roof sheathing panel system)을 대상으로 ASCE(American Society of Civil Engineers) 풍하중 기준을 적용한 취약도 평가 방법론의 결과와 비교·검증되었다. 본 연구는 국내 건축구조기준의 풍하중 산정식을 이용하여 강 풍 취약도의 평가 방법론을 보이며, 제안된 방법론에 의한 강풍 취약도는 기존 ASCE 기반 방법론의 결과와 비교하여 작은 오차 범위 내에서 잘 일치함이 확인되었다. 본 연구에서 제시한 강풍 취약도 평가 방법론은 자연재해저감계획 등에 따른 강풍 피해 예측 시 취약 도 구축 방법으로 적용될 수 있을 것으로 판단된다.

본 글은 특수고용형태근로종사자와 프리랜서 노동의 취약성을 2020년 상반기 경남의 특고/프리랜스 재난지원금 지원을 받은 인력을 대상으로 한 설문조사 자료를 분석한 후 정책적 시사점을 탐색하였다. 본 글의 내용은 크게 다음의 두가지로 나눠볼 수 있다. 첫째, 실증적 자료 분석상 특수고용형태종사자와 프리랜스 직종 종사자들의 경우 월 임금, 가계 급여수준, 근로조건, 노동시간, 각종 직업 만족도와 그 요인 등을 분석하면 직종별 특이성이 매우 부각된다는 점을 도출하였다. 둘째, 이런 결과가 정책적 방향에 주는 시사점을 탐색하였다. 분석결과 이 직종들의 종사자는 직종내 변이보다 직종간 변이가 도드라져 직종 간의 근로조건, 임금, 작업양태와 내용 등에서 많은 차이가 있음을 발견한다. 대체로 대부분의 직종이 경기에 따른 소득 변동성이 큰데 그 중에서 가장 소득 변동성이 큰 직종은 대출모집인, 보험모집인 등이었다. 월보수에서 변동급비율이 가장 높은 직종은 퀵서비스기사, 대출모집인, 보험모집인 등이었다. 일주일 평균노동시간이 많은 직종은 간병도우미와 택배기사였고 임금수준만족도가 낮은 직종은 대리운전기사였고, 노동강도와 업무 난이도 등에서 만족도가 낮은 직종은 택배기사로 나타났다. 코로나로 인한 직종 전체의 일감은 평균적으로 약 62% 감소하였으나 이 중 가장 일감감소분이 큰 직종은 방과후교사로 약 84%의 일감이 코로나로 인해 사라진 것으로 나타나고 있다. 이 같이 직종별로 차별화된 특징이 부각되는데 각 국가를 비롯해 한국에서 이들을 보호하는 정책은 대체로 비슷한 방향으로 나아가고 있었다. 본 글은 한국을 비롯한 세계 각국의 정책 방향이 특수고용 및 플랫폼 노동의 개념을 기존 노동자 개념에서 확장한 노무제공자란 형태로 구성되고 있다는 점을 지적하고 이들을 기존의 노동법이나 사회보험적 보호 영역으로 포함하는 보편적인 정책적 방향에 부가하여 각 직종별 특이성을 보완하는 정책적 방향이 보완적으로 필요함을 주장한다. 구체적으로는 특수고용이나 플랫폼 노동 등 각 직종별 특이적 조건을 보완하기 위한 가장 효과적인 방안은 각 직종별 집단적 대변기제가 형성되어 노사 및 이해 관계자 간의 자율적인 거버넌스 구조가 형성되는 것이란 입장을 취하고 있다.

배전기 캐비닛은 발전소와 같은 플랜트 시설에서 전자기기 혹은 시스템 컨트롤러 등을 보관하는 역할을 한다. 전기 캐비닛이 지진과 같은 외부하중에 의해 손상될 경우 시스템 장애 혹은 운영 중단이 발생할 수 있다. 안정적이고 지속가능한 에너지 공급을 위해 외부 하중에 의한 전기 캐비닛의 안전성 평가는 매우 중요하다. 전기 캐비닛은 주로 콘크리트 슬래브에 앵커 로 지지되기 때문에 앵커의 지지력 상실로 인해 전기 캐비닛이 손상될 수 있다. 콘크리트 재료는 다양한 불확실성이 존재하며 변동성이 다른 재료에 비해 큰 편이다. 따라서 본 연구에서는 선행연구에서 개발된 전기 캐비닛-앵커 시스템의 유한요소 모델을 이용하여 콘크리트 재료의 불확실성을 고려한 지진 취약도 평가를 수행하였다. 30개의 콘크리트 재료 모델을 라틴 하이퍼큐브 샘플링을 이용하여 샘플링하였으며 울진 지역의 등재해도 스펙트럼을 만족하는 인공지진을 적용하여 시간이력 해석을 수행하였다. 앵커의 응력과 캐비닛 최상단의 변위를 한계상태로 정의하였다. 지진 취약도 분석 결과 0.2g를 초과할 때 앵커의 응력 및 캐비닛 최상단 변위가 정해진 한계상태를 초과하는 것으로 나타났으며 대부분 0.5g에서 파괴되는 것으로 나타났다. 추후 연구에서는 지진의 불확실성과 재료의 불확실성을 동시에 고려하여 지진 취약도 평가를 수행하고자 한다.

Seismic fragility functions for unreinforced masonry buildings were derived based on the incremental dynamic analysis of eight representative inelastic numerical models for application to Korea's earthquake damage estimation system. The effects of panel zones formed between piers and spandrels around openings were taken into account explicitly or implicitly regarding stiffness and inelastic deformation capacity. The site response of ground motion records measured at the rock site was used as input ground motion. Limit states were proposed based on the fraction of structural components that do not meet the required performance from the nonlinear static analysis of each model. In addition to the randomness of ground motion considered in the incremental dynamic analysis explicitly, supplementary standard deviation due to uncertainty that was not reflected in the fragility assessment procedure was added. The proposed seismic fragility functions were verified by applying them to the damage estimation of masonry buildings located around the epicenter of the 2017 Pohang earthquake and comparing the result with actual damage statistics.

Seismic fragility analysis of a structure is generally performed for the expected critical component of a structure. The seismic fragility analysis assumes that all the components behave independently in a structural system. A bridge system consists of many inter-connected components. Thus, for an accurate evaluation of the seismic fragility of a bridge, the seismic fragility analysis requires the composition of probabilities considering the correlation between structural components. This study presented a procedure to obtain the seismic fragility curve of a bridge system, considering the correlation between bridge components. Seismic fragility analysis was performed on a PSC bridge that is considered as the central infrastructure. The analysis results showed that the probability of the seismic fragility curve of the bridge system was higher than that of each bridge component.

Nuclear power plants in Korea were designed and evaluated based on the NRC's Regulatory Guide 1.60, a design response spectrum for nuclear power plants. However, it can be seen that the seismic motion characteristics are different when analyzing the Gyeongju earthquake and the Pohang earthquake that has recently occurred in Korea. Compared to the design response spectrum, seismic motion characteristics in Korea have a larger spectral acceleration in the high-frequency region. Therefore, in the case of equipment with a high natural frequency installed in a nuclear power plant, seismic performance may be reduced by reflecting the characteristics of domestic seismic motions. The failure modes of the equipment are typically structural failure and functional failure, with an anchorage failure being a representative type of structural failure. In this study, comparative analyses were performed to decide whether to consider the inelastic behavior of the anchorage or not. As a result, it was confirmed that the seismic performance of the anchorages could be increased by considering the inelastic behavior of an anchorage.

Current seismic fragility functions for buildings were developed by defining damage state threshold based on story drift concerning foreign references and using the capacity spectrum method based on spectral displacement. In this study, insufficient details and dependence on the core location of piloti-type buildings were not reflected in the fragility function because it was developed before the Pohang earthquake. In order to develop an improved one for piloti-type buildings, several types of core were selected, damage state threshold was determined based on the capacity of structural members, and three-dimensional analyses were utilized. As a result, seismic fragility functions based on spectral acceleration were developed for various core locations and different shear strengths of the column stirrup. The fragility of piloti-type buildings significantly varied according to core location, an additional single wall, and whether the contribution of column stirrup was included or not. To estimate fragility more reasonably, it is necessary to prepare the parameters to reflect actual state well.