Piloti-type buildings are widely constructed in urban areas of South Korea. Due to stiffness irregularities, piloti-type buildings are vulnerable to lateral loads such as earthquakes. Although seismic retrofitting is necessary for piloti-type buildings, many of these structures are privately owned, and the extensive number of buildings creates significant challenges in terms of cost and time for regional seismic performance evaluation. This study proposes a methodology for determining the seismic performance of multiple piloti-type buildings within a region by utilizing structural parameters. Information on piloti-type buildings is classified into public building data and exterior building data, which are integrated to define structural parameters for estimating the first natural period of the buildings. Linear regression analysis was performed to develop a regression equation correlating structural parameters with the natural period. Additionally, the natural period and structural parameters are used to perform another linear regression analysis to estimate the yield and ultimate points of the capacity curve. The capacity curves derived from the regression equations facilitate seismic performance evaluation based on structural parameters.

In densely populated urban areas, reinforced concrete residential buildings with an open first floor and closed upper floors are preferred to meet user demands, resulting in significant vertical stiffness irregularities. These vertical stiffness irregularities promote the development of a soft-story mechanism, leading to concentrated damage on the first floor during seismic events. To mitigate seismic damage caused by the soft-story mechanism, stiffness-based retrofit strategies are favored, and it is crucial to determine an economically optimal level of retrofitting. This study aims to establish optimal seismic retrofit strategies by evaluating the seismic losses of buildings before and after stiffness-based retrofitting. An equivalent single-degree-of-freedom model is established to describe the seismic response of a multi-degree-of-freedom model, allowing for seismic demand analysis. By convolving the seismic loss function with the hazard curve, the annual expected loss (EAL) of the building is calculated to assess the economic losses. The results show that stiffness-based retrofitting increases first-story lateral stiffness by 20-40%, enhancing structural seismic performance, but also results in a rise in EAL compared to the as-built state, indicating lower cost-effectiveness from an economic perspective. The research concludes that retrofit options that increase first-story lateral stiffness by at least 60% are more appropriate for reducing financial losses.

산악 지역이 대부분인 한국에서는 많은 깎기비탈면이 사회기반시설 건설사업의 일환으로 조성된다. 경주지역에 서는 초기 깎기비탈면 설계 시 깎기비탈면의 안정성을 평가하기 위해 암종 및 지질구조 파악을 위한 시추 및 지표지질 조사를 실시하였다. 또한, RMR (Rock Mass Rating), SMR (Slope Mass Rating), 입체투영법, 한계평형분석 등을 이용 하여 사면안정성을 정량적으로 평가하였다. 본 연구에서는 경주지역의 토사층과 풍화암으로 구성된 깎기비탈면은 총길이 110m, 높이는 10-19 m, 경사도는 51/175-155 (경사/경사방향)로 구성되어 있으며, 시추결과에 따라 3개 구역(A, B, C)으로 구분하였다. 구역 A에서 사면에 대한 수많은 불연속성과 준평행 절리가 관찰되어 평면 파괴의 위험이 있는 것 으로 분석되었으며, 이로 인해 불안정하고 풍화가 심한 깎기비탈면에 대한 보강 작업을 하였다. 한계 평형 분석에 따르 면, 세 구역 모두의 깎기비탈면은 건기와 지진 조건에서 모두 불안정한 것으로 분석되었다. 이 분석을 바탕으로 국토교 통부가 정한 사면 안전 계수 기준과 시공성, 경제적 타당성과 같은 현장 특정 조건을 고려하여 깎기비탈면에 대한 마 이크로파일 보강재를 적용하였다. 이 연구는 복합 비탈면의 안정성평가와 적합한 보강 공법 선택에 실무적 방법론을 제 공하며, 유사 지역의 비탈면 설계 및 관리에 기여할 수 있다.

국내에서 지진 발생빈도가 증가함에 따라 다가구주택 필로티기둥의 내진보강이 필수적이다. FRP 패널은 경량성과 고강도를 갖춘 내진 보강재료 사용되고 있으나, 상대적으로 낮은 임계온도로 인해 화재에 취약하다. 따라서 FRP 패널로 보강된 RC 기둥의 내화 성능을 확보할 방안이 필요하다. 본 연구에서는 FRP 패널로 보강된 RC 기둥의 내화성능을 평가하기 위해, FRP 패널의 열적특성(비열, 열전도율, Weight loss)을 확인하는 소재시험을 진행하였다. 또한, FRP 패널로 보강된 RC 단주기둥에 뿜칠을 도포하고, 표준화재 1시간 동안의 온도거동을 분석하였다.

지진발생 시, 건물은 작게는 손상에서 크게는 붕괴까지 이어지므로 인명과 재산상의 피해가 생길 수 있다. 이러한 지진의 위험성에 대비하여 건물의 내진성능평가가 필요하다. 현재 내진성능평가 기법의 경우 개별 건물을 대상으로 하기에 많은 시간이 투자되어야 한다. 따라서, 지역규모의 건물들을 대상으로 하는 내진성능평가 기법의 개발이 필요한 실정이다. 본 연구는 RC 주거형 건물의 내진 성능을 평가하고 보강계획을 수립하기 위해 비선형 Shear Spring을 가진 단자유도모델을 구축하였다. 구조물의 비선형 응답을 모사 하기 위한 비선형 Shear Spring은 T-SR-μ를 매개변수로 정의된다. 해당모델에 100개의 PEER 지진을 적용하여, 최대층간변위비 응답 으로 건물의 내진성능을 평가하였다. 제안기법의 적용성을 확인하기 위하여 상세모델과 비교하였을 때, 두 모델 모두 건물의 내진성 능을 같은 수준으로 판단하였음을 확인하였다. 본 연구는 제안된 방식이 실제 건물의 내진성능을 예측할 수 있음을 보여주었다.

Many school buildings are vulnerable to earthquakes because they were built before mandatory seismic design was applied. This study uses machine learning to develop an algorithm that rapidly constructs an optimal reinforcement scheme with simple information for non-ductile reinforced concrete school buildings built according to standard design drawings in the 1980s. We utilize a decision tree (DT) model that can conservatively predict the failure type of reinforced concrete columns through machine learning that rapidly determines the failure type of reinforced concrete columns with simple information, and through this, a methodology is developed to construct an optimal reinforcement scheme for the confinement ratio (CR) for ductility enhancement and the stiffness ratio (SR) for stiffness enhancement. By examining the failure types of columns according to changes in confinement ratio and stiffness ratio, we propose a retrofit scheme for school buildings with masonry walls and present the maximum applicable stiffness ratio and the allowable range of stiffness ratio increase for the minimum and maximum values of confinement ratio. This retrofit scheme construction methodology allows for faster construction than existing analysis methods.

In South Korea, over 400,000 Non-building Structures are inadequately managed and exposed to potential risks due to insufficient inspection systems, leading to an increase in accidents and significant losses of life and property. Therefore, it is crucial for users to conduct proactive self-inspections to identify and mitigate potential hazards. This study reclassified Non-building Structures into four main categories by analyzing their structural characteristics and associated risks through statistical analysis. Among these, retaining walls, which account for the largest proportion, were systematically analyzed to identify common damage patterns. Based on this analysis, self-inspection checklists were developed for both non-experts and experts. The proposed process involves an initial visual inspection using a simple non-expert checklist, followed by a more detailed expert-level inspection if any anomalies are detected. The reliability of this process was validated through approximately 120 validation processes.

The adhesive design of a fast steering mirror transmitting a high power laser is one of the important design elements that affect optical aberration of the mirror surface. In this paper, we designed the adhesive part to avoid the high power laser beam of the FSM system. Stiffness and wavefront error are trade-off relationships and an optical design was derived to maintain the wavefront error of the mirror surface at high temperatures while satisfying the bandwidth of the FSM system. For the optimal design of the mirror bonding position, structural analysis was conducted using ANSYS and wavefront error analysis was performed using Zernike polynomial code. Through those analysis, FSM most effective at an angle 60 degrees and a distance of 46mm.

원자력발전소(원전) 시스템 내진성능 평가를 위하여 구조물내응답스펙트럼(ISRS)은 필수적으로 요구된다. 특히, 원전 부지 고유 스펙트럼 변경 시 새로운 ISRS 도출이 요구될 경우 지진 재해석 등의 상당한 비용을 필요로 하게 된다. 따라서 이 연구는 지진 재해석 이 필요 없는 ISRS 스케일링 근사 방법에 대한 여러 가지 접근법을 제공한다. 이러한 접근법으로 도출한 ISRS는 정확한 ISRS와 비교 한다. 근사 방법의 ISRS 가 원전 주요 시스템 지진응답 및 내진성능에 미치는 영향을 분석한다. 결과적으로 본 연구에서 제시한 ISRS 스케일링 근사 방법은 저주파에서 비교적 유사하게 ISRS를 도출하지만, 고주파에서는 그 정확도가 감소하였다. ISRS 스케일링 근사 방법이 시스템 지진응답/내진성능 산출 정확도에 미치는 영향은 방법의 시스템 주요 모드 응답 유사도 산출 정도에 따라 결정된 것을 확인할 수 있었다.

This study divided the area capable of producing domestic forage into grazing pasture, hay production area, and silage crop area, calculated the required area according to the forage production volume, and examined whether self-sufficiency in forage leads to cost savings. When the self-sufficiency rate of forage for dairy cows and Hanwoo is 80%, the improvement in profitability per heaf ranges from 3% to 9%, typically around 5%, which is considered a significant benefit for both corporate and individual businesses. The average profit per ranch is expected to increase about KRW 50 million per year, and the country as a whole is expected to reduce forage costs by KRW 0.9 trillion per year. Recently, efforts are being made by the government and local authorities to cultivate summer forage at the rice fields for improving self-sufficiency in forage feed to stabilize rice supply and demand. Furthermore, it is also necessary to conduct research on reducing the cost of concentrated feed and TMR (Total mixed ration).

As a means to activate eco pastoral system in alpine grassland, the government can consider public pastures, which are currently unused, to scale them up into public ranches. Depending on ownership and operation, four management models proposed as follows: 1) Government-Owned and Operated with Balanced Profit and Loss 2) Government-Owned and Operated with Revenue Generation 3) Government-Owned but Privately Operated by Outsourced to Professional Manager 4) Full Privatization (Ownership and Operation by Private Individuals). The study outlined above proposes four management models for the activation of eco pastoral system in alpine grassland. It also suggests methods for the selection and performance evaluation of manager to establish a profitable structure. Additionally, the research provides management methods for the conservation of grazing ecology in pastoral ecosystems. Particularly, the adaptation of tools commonly used in South Korean business sector for the selection and performance evaluation of manager within the system of the proposed management models. This aspect is deemed valuable as it aligns these tools with the specific characteristics of eco pastoral system in alpine grassland, contributing not only to the effective implementation of the models but also to the enhancement of the revenue structure.