• Wind and Structures
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• 제10권6호
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• pp.543-554
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• 2007

The suspension bridge is situated in an area of complex topography with both open sea and overland turbulence characteristics, and it is subject to frequent typhoon occurrences. This paper investigates experimentally the possible vortex shedding events of the structure under high wind and typhoon conditions. A single-degree-of-freedom model for the vibration of a unit bridge deck section is adopted to determine the amplitude of vibration and to estimate the parameters related to the lifting force in a vortex shedding event. The results of the studies are presented in a companion paper (Law, et al. 2007). In this paper, statistical analysis on the measured responses of the bridge deck shows that the vibration response at the first torsional mode of the structure has a significant increase at and beyond the critical wind speed for vortex shedding as noted in the wind tunnel tests on a section model of the structure.

• Wind and Structures
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• 제9권5호
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• pp.397-412
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• 2006

This paper presents the wind excited acceleration responses of a 50 m guyed mast under the action of Typhoon Dujuan. The response of the structure is reconstructed from using a full finite element model and an equivalent beam-column model. The wind load is modelled based on the measured wind speed and recommendations for high-rise structures. The nonlinear time response analysis is conducted using the Newton Raphson iteration procedure. Comparative studies on the measured and computed frequencies and acceleration responses show that the torsional vibration of the structure is significant particularly in the higher vibration modes after the first few bending modes. The equivalent model, in general, gives less accurate amplitude predictions than the full model because of the omission of torsional stiffness of the mast in the vibration analysis, but the root-mean-square value is close to the measured value in general with an error of less than 10%.

• Wind and Structures
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• 제7권5호
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• pp.345-357
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• 2004

In the 1990s, four strong typhoons hit the Kyushu area of Japan and inflicted severe damage on power transmission facilities, houses, and so on. Maximum gust speeds exceeding 60 m/s were recorded in central Kyushu. Although the wind speeds were very high, the gust factors were over 2.0. No meteorological stations are located in mountainous areas, creating a deficiency of meteorological station data in the area where the towers were damaged. Since 1995 the authors have operated a network for wind measurement, NeWMeK, that measures wind speed and direction, covering these mountainous areas, segmenting the Kyushu area into high density arrays. Maximum gusts exceeding 70 m/s were measured at several NeWMeK sites when Typhoon Bart (1999) approached. The gust factors varied widely in southerly winds. The mean wind speeds increased due to effects of the local terrain, thus further increasing gust speeds.

• 한국농촌건축학회논문집
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• 제14권4호
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• pp.117-124
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• 2012

The purpose of this study is the impact of the typhoon damage to housing and facilities in rural areas. House of damage, as well as the only including damage of facilities in rural areas, particularly greenhouse(Glass greenhouse, Plastic greenhouse, Vinyl greenhouse) leads to damage of crops the scale of the damage increases. In this study, focused on Jeollabuk-do area, accompanying him, the number of gale damage and evaluate the extent of the damage to the typhoon. And aims to provide basic data for the rural areas of strong winds and typhoons preparedness and facility design based on the results. Judging from the results of the analysis of natural disasters caused by typhoons and strong winds, the city formed mainly in the area than in the plains or coastal rural areas compared to other areas more damage can appear. In recent years, many design maximum wind speed of 40m/s wind over because disaster type, even if the standard installation, preferably determined through a precise structural analysis to ensure the structural history of acting urgently.

• 한국산림과학회지
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• 제100권2호
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• pp.246-255
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• 2011

본 연구는 2010년 9월 2일 강한 바람으로 우리나라 중부 지방에 영향을 미친 제7호 태풍 곤파스로 인해 피해를 입은 홍릉수목원 내 풍도목을 대상으로 풍도목의 특징, 임내 외 풍향 및 풍속의 특징을 구명하고자 실시하였다. 풍도목은 피해 유형에 따라 바람에 쓰러진 나무, 기울어진 나무, 수간이 부러진 나무 등 크게 세 가지로 구분하여 조사하였다. 바람이 불기 시작한 9월 2일 04시부터 바람이 완전히 멎은 12시까지의 풍속을 분석한 결과, 임내 평균풍속과 순간최대풍속은 각각 1.4 m/s와 3.5 m/s 이었으며, 06시 10분 임내 평균풍속과 순간최대풍속이 각각 3.4 m/s와 8.7 m/s로 최고치를 기록하였다. 곤파스의 피해를 받은 2010년 9월 2일과 강풍주의보가 발효되었던 과거 5일(2009년 2월 13일, 2월 20일, 4월 21일, 10월 16일, 2010년 3월 20일)의 평균풍속 차이와 파동을 비교 분석한 결과, 풍도목 발생 원인은 바람의 세기보다는 단위시간당 바람파동횟수와 관련이 깊은 것으로 사료된다. 풍향 분석 결과 임내 평균풍향은 방위각 $112.5^{\circ}{\sim}180^{\circ}$(ESE-SE-SSE-S)와 $247.5^{\circ}$(WSW) 방향에서 불어 들어왔으며, 임내 외 순간 최대풍향 모두 방위각 $157.5^{\circ}$(SSE) 방향에서 강하게 불어 들어왔다. 풍도목의 도복 방향과 위치를 분석한 결과 84.0%의 풍도목이 방위각 $270^{\circ}{\sim}22.5^{\circ}$(W-WNW-NW-NNW-N-NNE) 방향으로 쓰러졌으며, 97.3%의 풍도목이 완경사지(경사 $15^{\circ}$ 미만)와 경사지(경사 $15^{\circ}{\sim}20^{\circ}$)에서 발생하였다. 풍도목 중 침엽수가 45.3%를 차지했고, 활엽수가 54.7%를 차지하였으나, 임상별로 보면 풍도목은 활엽수림보다 침엽수림과 혼효림에서 주로 발생한 것으로 나타났다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.231-232
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• 2023

With taller buildings and larger typhoons, the impact of building winds is growing. During the 11th Typhoon Hinnamno in 2022, the building wind in Busan L City exceeded 60m/s, reaching the highest speed ever. Although many studies have been conducted on reducing the wind load of buildings, which is one of the problem factors caused by strong wind speed, there is a lack of research on wind speed reducing sculptures that can directly control strong wind speed. In this paper, several types of wind speed reduction sculptures were proposed to solve these problems, and the wind speed reduction capability of the proposed sculptures was analyzed through computational fluid dynamics (CFD). These results can contribute to suggesting effective design methods for improving the urban environment and reducing pedestrian stress.

• 한국환경과학회지
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• 제30권9호
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• pp.763-777
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• 2021

The spatial characteristics of typhoon-class strong wind during the non-typhoon period were analyzed using, a cluster analysis of the observational data and of special strong wind advisories and, warnings issued by the Korean Meteorological Administration. On the Korean Peninsula, strong winds during non-typhoon periods showed a wide variety of spatial characteristics. In particular, the cluster analysis showed that strong winds could be classified into six clusters on the Korean Peninsula, and that the spatial distribution, occurrence rate of strong winds, and strong wind speed in each cluster were complex and diverse. In addition, our analysis of the frequency of issuance of special strong wind warnings showed a significant difference in the average frequency of strong wind warnings issued in metropolitan cities, with relatively high numbers of warnings issued in Gyeongsangbuk-do and, Jeollanam-do, and low numbers of warning issued inland and in other metropolitan cities. As a result of the changing trend in warnings issued from 2004 to 2019, Ulsan and Busan can be interpreted as having a relatively high number of warnings; the frequency of strong wind warnings issuances and strong wind occurrences in these cities is increasing rapidly. Based on the results of this study, it is necessary to identify areas with similar strong wind characteristics and consider specific regional standards in terms of disaster prevention.

• Wind and Structures
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• 제14권3호
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• pp.253-283
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• 2011

This paper presents the field measurement results of wind effects on a super-tall building (CITIC Plaza, 391 m high) located in Guangzhou. The field data such as wind speed, wind direction and acceleration responses were simultaneously and continuously recorded from the tall building by a wind and vibration monitoring system during two typhoons. The typhoon-generated wind characteristics including turbulence intensity, gust factor, peak factor, turbulence integral length scale and power spectral density of fluctuating wind speed were presented and discussed. The dynamic characteristics of the tall building were determined based on the field measurements and compared with those calculated from a 3D finite element model of the building. The measured natural frequencies of the two fundamental sway modes of the building were found to be larger than those calculated. The damping ratios of the building were evaluated by the random decrement technique, which demonstrated amplitude-dependent characteristics. The field measured acceleration responses were compared with wind tunnel test results, which were found to be consistent with the model test data. Finally, the serviceability performance of the super-tall building was assessed based on the field measurement results.

• Nuclear Engineering and Technology
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• 제47권1호
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• pp.59-65
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• 2015

Background: After the Fukushima accident, the importance of hazard analysis for extreme external events was raised. Methods: To analyze typhoon-induced hazards, which are one of the significant disasters of East Asian countries, a statistical analysis using the extreme value theory, which is a method for estimating the annual exceedance frequency of a rare event, was conducted for an estimation of the occurrence intervals or hazard levels. For the four meteorological variables, maximum wind speed, instantaneous wind speed, hourly precipitation, and daily precipitation, the parameters of the predictive extreme value theory models were estimated. Results: The 100-year return levels for each variable were predicted using the developed models and compared with previously reported values. It was also found that there exist significant long-term climate changes of wind speed and precipitation. Conclusion: A fragility analysis should be conducted to ensure the safety levels of a nuclear power plant for high levels of wind speed and precipitation, which exceed the results of a previous analysis.

• 한국방재학회 논문집
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• 제8권3호
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• pp.29-36
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• 2008

본 연구의 목적은 동 서해를 중심으로 한반도 주변 해역을 통과하는 태풍과 관련된 재해 특성을 조사하는 것이다. 먼저, 1951년부터 2006년까지 Regional Specialized Meteorological Center (RSMC)-Tokyo의 태풍 자료를 이용하여 한반도에 영향을 준 태풍을 우리나라의 서해와 동해를 통과하는 사례로 구분하고, 각 사례별로 연도별 및 월별의 빈도와 강도에 대해 분석하였다. 특히, 1973년부터 2006년까지의 기간에 대해서는 사례별 태풍 재해의 규모를 파악하여 비교하였다. 서해를 통과하는 태풍의 발생빈도는 거의 변화가 없고 강도가 약한 반면에 동해를 통과하는 태풍의 발생빈도는 증가하는 추세를 보이고 강도가 점차 강해지고 있다. 동해를 통과하는 태풍의 경우에는 집중호우에 의한 침수면적과 농경지피해가 크게 나타났으며, 서해를 통과하는 경우에는 주택, 선박, 도로 및 교량 등 강풍에 의한 시설물 파손에 의한 피해가 크게 발생하였다. 태풍 재해 발생과 관련하여 강수량과 최대풍속 자료를 비교 분석한 결과, 동해를 통과한 태풍의 경우는 집중호우, 서해를 통과한 태풍은 강한 바람에 의한 영향이 크게 나타난 것으로 보였다.