Wind Risk Assessment for Building Cladding Considering Changes to Future Wind Speeds in South Korea

Ham Hee Jung,Choi Seung Hun,Lee Sungsu 한국풍공학회 2019 한국풍공학회지 Vol.23 No.3

본 연구에서는 한국에 대한 기후변화로 인한 미래 풍속의 변화를 예측하고, 건축물 외장재에 대한 풍해 위험도를 정량적으로 평가하였다. 미래의 기후변화로 인한 풍속의 변화를 예측하기 위해서 기상청에서 제공하는 RCP 시나리오와 HadGem3-RA 모델을 사용한 풍속 변화 예측치에 관한 이전 연구의 결과가 활용되었다. 강풍에 대한 위험도는 임의의 풍속에 대한 손상확률인 강풍 취약도 모델과 강풍이 발생할 확률인 강풍 위험 모형의 결과를 합성곱하여 평가 되었다. 강풍 취약도 모델은 몬테카를로 모사(Monte-Carlo simulation)를 사용하여 개발되었으며, 강풍 위험모델은 과거 태풍에 대한 자료와 몬테카를로 모사를 사용한 강풍의 발생확률 분석에 관한 이전 연구의 결과를 기초로 개발되었다. 본 연구에서는 강풍 위험도 연구의 결과를 기초로 미래 풍속의 변화로 인한 건축물의 강풍 위험도 변화를 정량적으로 분석하였다. 연구결과로부터 서울보다 남쪽 지역인 부산에 미래 강풍이 더 발생하는 것으로 파악되었다. 또한, RCP 4.5와 RCP 8.5 시나리오 하에서 부산에서의 미래 풍속의 차이가 크지 않기 때문에 강풍 위험도의 변화 역시 크지 않은 것으로 평가되었다. 본 연구에서 제안한 방법론은 미래 강풍으로 인한 피해를 예측하고 대비하기 위한 방법으로 사 용될 수 있을 것으로 판단된다. 본 연구에서의 강풍 위험도 평가를 국가 차원에 적용하기 위해서는 강풍 위험에 대한 공간적 확장과 더불어 피해 대상물에 대한 강풍 취약도의 추가적인 개발이 필요할 것으로 판단된다. This study quantitatively assesses the risk of wind damage to building cladding by predicting future changes in wind speeds caused by climate change in South Korea. In order to predict changes in wind speed due to future climate change, the results of a previous study that predicted changes in the wind speed in South Korea using the HadGem3-RA model and the RCP scenarios provided by the Korea Meteorological Administration were utilized. The wind risk was then assessed using a convolution of the wind fragility model, representing the probability of failure due to an arbitrary wind speed, and the wind hazard model, representing the probability of occurrence of strong wind speed. The wind fragility model was developed using a Monte-Carlo simulation, while the wind hazard model was taken from a previous study that analyzed the probability of occurrence of typhoon-induced strong wind speeds around South Korea using past typhoon historical data and the Monte-Carlo simulation method. Based on the results of the wind risk assessment, the changes in wind risk due to future changes in wind speed were quantitatively compared. From the results, the high wind speeds occur more in the southern region of South Korea where typhoons mostly pass, than they do Seoul. In additionally, there is no change in the wind risk for Busan because the changes in the wind speed are insignificant under both RCP 4.5 and RCP 8.5. The methodology of this study can be used as a basis for predicting and preparing for future wind-induced damage. It is necessary to expand the target structures for wind fragility assessment as well as the assessment areas of the wind hazard to evaluate wind risk for the national level.

최근 기상자료에 의한 지표면조도구분별 돌풍률 평가

김병조,하영철 한국풍공학회 2015 한국풍공학회지 Vol.19 No.2

Design wind speeds for estimating wind loading of structures were based on the 10 minute mean wind speed or the gust wind speed having 3 second averaging time. The 10 minute mean wind speed might be applied to estimate wind load of buildings and the 3 second gust wind speed might be applied to high frequency structures such as claddings. The gust wind speed is affected by the conditions of surroundings, so it convenient to estimate gust wind speed by the product of gust factor and 10 minute mean wind speed. This study estimates gust factor suitable for the surface roughness categories, which is reflecting a severe change of surface roughness by rapid urbanization process and recent abnormal weather by global warming. Wind speed values are established from data of 10-minute mean and 3 second gust wind speed collected at 68 meteorological offices recent past 40 years from 1973 to 2012 and surface roughness categories are used previous study result. For estimating gust factor, it is assumed that the range of maximum monthly value of mean wind speed has limited from 16m/s to 18m/s and gust factors have constant value, if wind speeds are below 16m/s or over 36m/s. By the results of study, it is known that gust factors of surface roughness category C are similar to those of B and gust factors of surface roughness category D are different from other categories. Therefore, empirical formula of gust factor on surface roughness category B and C was suggested on the same type and on surface roughness category D was suggested on different type. 구조물의 풍하중을 산정할 때의 설계풍속은 10분 평균풍속 또는 가스트풍속(3초평균풍속)을 적용한다. 건축물의 경우 10분 평균풍속 사용하고 있으나, 외장재 등과 같이 고진동수를 가지는 구조물의 경우에는 가스트풍속을 사용한다. 가스트풍속은 기상대 주변의 영향을 크게 받기 때문에, 일반적으로 10분 평균풍속에 돌풍율을 곱하여 산정하는 것이 편리하다. 본 연구는 최근 우리나라의 기상변화와 경제 발전에 따른 기상대 주변의 지표면상태의 변화를 반영하여 지표면조도에 알맞은 돌풍률을 평가한 것이다. 해석자료는 최근 40년간(1973년~2012년)의 전국 68개 기상관측소의 기상자료와 선행연구에서 제시한 지표면조도구분을 활용하였다. 돌풍률을 추정할 때 평균풍속의 월최대값 범위는 16m/s~36m/s로 하였고, 16m/s 이하와 36m/s 이상에서는 돌풍률을 일정하게 하였다. 연구결과 지표면조도구분 B지역과 C지역의 돌풍률은 거의 유사하게 나타났고, 지표면조도구분 D지역은 다른 지역의 돌풍률과 차이를 보였다. 따라서 지표면조도구분 B, C지역의 돌풍률은 통합하여 평가하였고, 지표면조도구분 D지역만 따로 분류하여 돌풍률을 평가하여 제시하였다.

기상청 주변의 지형 및 지표면 조도를 고려한 기본풍속 산정 방안 연구

김진호,김준영 한국풍공학회 2017 한국풍공학회지 Vol.21 No.4

Recently, as the wind induced damages are on the increase, design wind speed was applied design of structure. Also, in order to estimate the design wind speed , the yearly maximum wind speed provided by the Korea Meteorological Agency is used. However, it provides the highest of the observed wind speeds increase or decrease by terrain effect or surface roughness. For these reasons, when performing extreme analysis using observation wind speed, the effect of the surface roughness and terrain be corrected for use. The maximum yearly wind speed was the maximum of the wind speed before correction and the maximum of the corrected wind speed should be used to ensure statistical significance. Therefore, in this study, the daily maximum wind speeds of 60 weather observation stations across the country with more than 40 years of observation data were corrected to basic wind speed conditions according to the topography and surface roughness. Besides, the maximum annual wind speed of the corrected maximum wind speed was selected, and the wind speed of the reproduction period was calculated through frequency analysis. Plus, the annual maximum wind speed was selected using the daily maximum wind speed before correction, and the selected annual maximum wind speed was corrected to compare with the calculated wind speed. As a result, the maximum difference of 4.2m/s was observed on the basis of the centurial reconstruction period wind speed, and the average difference was about 0.33m/s. 최근 강풍으로 인한 시설물 피해가 증가함에 따라 구조물 설계 시 설계풍속을 반영하고 있으며, 설계풍속 산정 시 기상청에 서 제공하고 있는 연최대풍속 년도별 풍속 자료를 활용한다. 하지만 기상청에서 제공하고 있는 연최대풍속은 지형이나 지표면조도에 의해 할증되거나 감소된 관측풍속 중 최댓값을 제공하고 있어 실제 기본풍속 조건에서의 연최대풍속과는 상이하기 때문에 기상청에 서 제공하는 연최대풍속을 활용하여 통계적 빈도분석을 수행할 경우 풍속이 과소 또는 과대평가 될 수 있다. 따라서 본 연구에서는 40 년치 이상의 관측자료가 있는 전국 60개 지점의 기상관측소의 일최대풍속을 지형 및 지표면 조도에 따라 기본풍속 조건으로 보정하고 보정된 일최대풍속 중 연최대풍속을 선별하여 빈도분석을 통해 재현기간 풍속을 산정하였으며, 보정하기 전의 일최대풍속을 이용하여 연최대풍속을 선별한뒤 선별된 연최대풍속을 보정하여 산정된 재현기간풍속과 비교·분석하였다. 분석 결과 100년 재현기간 풍속 기준 으로 최대 4.2m/s 차이를 보였으며, 평균적으로 약 0.33m/s의 차이를 보였다.

Joint distribution of wind speed and direction in the context of field measurement

Hao Wang,Tianyou Tao,Teng Wu,Jianxiao Mao,Aiqun Li 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.5

The joint distribution of wind speed and wind direction at a bridge site is vital to the estimation of the basic wind speed, and hence to the wind-induced vibration analysis of long-span bridges. Instead of the conventional way relying on the weather stations, this study proposed an alternate approach to obtain the original records of wind speed and the corresponding directions based on field measurement supported by the Structural Health Monitoring System (SHMS). Specifically, SHMS of Sutong Cable-stayed Bridge (SCB) is utilized to study the basic wind speed with directional information. Four anemometers are installed in the SHMS of SCB: upstream and downstream of the main deck center, top of the north and south tower respectively. Using the recorded wind data from SHMS, the joint distribution of wind speed and direction is investigated based on statistical methods, and then the basic wind speeds in 10-year and 100-year recurrence intervals at these four key positions are calculated. Analytical results verify the reliability of the recorded wind data from SHMS, and indicate that the joint probability model for the extreme wind speed at SCB site fits well with the Weibull model. It is shown that the calculated basic wind speed is reduced by considering the influence of wind direction. Compared to the design basic wind speed in the Specification of China, basic wind speed considering the influence of direction or not is much smaller, indicating a high safety coefficient in the design of SCB. The results obtained in this study can provide not only references for further wind-resistance research of SCB, but also improve the understanding of the safety coefficient for wind-resistance design of other engineering structures in the similar area.

Joint distribution of wind speed and direction in the context of field measurement

Wang, Hao,Tao, Tianyou,Wu, Teng,Mao, Jianxiao,Li, Aiqun Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.5

The joint distribution of wind speed and wind direction at a bridge site is vital to the estimation of the basic wind speed, and hence to the wind-induced vibration analysis of long-span bridges. Instead of the conventional way relying on the weather stations, this study proposed an alternate approach to obtain the original records of wind speed and the corresponding directions based on field measurement supported by the Structural Health Monitoring System (SHMS). Specifically, SHMS of Sutong Cable-stayed Bridge (SCB) is utilized to study the basic wind speed with directional information. Four anemometers are installed in the SHMS of SCB: upstream and downstream of the main deck center, top of the north and south tower respectively. Using the recorded wind data from SHMS, the joint distribution of wind speed and direction is investigated based on statistical methods, and then the basic wind speeds in 10-year and 100-year recurrence intervals at these four key positions are calculated. Analytical results verify the reliability of the recorded wind data from SHMS, and indicate that the joint probability model for the extreme wind speed at SCB site fits well with the Weibull model. It is shown that the calculated basic wind speed is reduced by considering the influence of wind direction. Compared to the design basic wind speed in the Specification of China, basic wind speed considering the influence of direction or not is much smaller, indicating a high safety coefficient in the design of SCB. The results obtained in this study can provide not only references for further wind-resistance research of SCB, but also improve the understanding of the safety coefficient for wind-resistance design of other engineering structures in the similar area.

A Study of Wind Characteristics around Nuclear Power Plants Based on the Joint Distribution of the Wind Direction and Wind Speed

이윤종 (사)한국방사선산업학회 2023 방사선산업학회지 Vol.17 No.3

Given that toxic substances are diffused by the various movements of the atmosphere, it isvery important to evaluate the risks associated with this phenomenon. When analyzing the behavioralcharacteristics of these atmospheric diffusion models, the main input data are the wind speed and winddirection among the meteorological data. In particular, it is known that a certain wind direction occursin summer and winter in Korea under the influence of westerlies and monsoons. In this study, synopticmeteorological observation data provided by the Korea Meteorological Administration were analyzedfrom January 1, 2012 to the end of August of 2022 to understand the regional wind characteristics ofnuclear power plants and surrounding areas. The selected target areas consisted of 16 weather stationsaround the Hanbit, Kori, Wolsong, Hanul, and Saeul nuclear power plants that are currently in operation. The analysis was based on the temperature, wind direction, and wind speed data at those locations. Average, maximum, minimum, median, and mode values were analyzed using long-term annualtemperature, wind speed, and wind direction data. Correlation coefficient values were also analyzed todetermine the linear relationships among the temperature, wind direction, and wind speed. Among the16 districts, Uljin had the highest wind speed. The median wind speed values for each region were lowerthan the average wind speed values. For regions where the average wind speed exceeds the medianwind speed, Yeongju, Gochang, Gyeongju, Yeonggwang, and Gimhae were calculated as 0.69 m s-1, 0.54m s-1, 0.45 m s-1, 0.4 m s-1, and 0.36 m s-1, respectively. The average temperature in the 16 regions was13.52 degrees Celsius; the median temperature was 14.31 degrees and the mode temperature was20.69 degrees. The average regional temperature standard deviation was calculated and found to be9.83 degrees. The maximum summer temperatures were 39.7, 39.5, and 39.3 in Yeongdeok, Pohang, andYeongcheon, respectively. The wind directions and speeds in the 16 regions were plotted as a wind rosegraph, and the characteristics of the wind direction and speed of each region were investigated. It wasfound that there is a dominant wind direction correlated with the topographical characteristics in eachregion. However, the linear relationship between the wind speed and direction by region varied from 0.53to 0.07. Through this study, by evaluating meteorological observation data on a long-term synoptic scaleof ten years, regional characteristics were found.

인공위성 고도계 해상풍 검증과 해상상태편차와의 관련성- 이어도, 마라도, 외연도 해상풍 관측치를 중심으로 -

최도영,우혜진,박경애,변도성,이은일 한국지구과학회 2018 한국지구과학회지 Vol.39 No.2

The sea surface wind field has long been obtained from satellite scatterometers or passive microwave radiometers. However, the importance of satellite altimeter-derived wind speed has seldom been addressed because of the outstanding capability of the scatterometers. Satellite altimeter requires the accurate wind speed data, measured simultaneously with sea surface height observations, to enhance the accuracy of sea surface height through the correction of sea state bias. This study validates the wind speeds from the satellite altimeters (GFO, Jason-1, Envisat, Jason-2, Cryosat-2, SARAL) and analyzes characteristics of errors. In total, 1504 matchup points were produced using the wind speed data of Ieodo Ocean Research Station (IORS) and of Korea Meteorological Administration (KMA) buoys at Marado and Oeyeondo stations for 10 years from December 2007 to May 2016. The altimeter wind speed showed a root mean square error (RMSE) of about 1.59 m s-1 and a negative bias of –0.35 m s-1 with respect to the in-situ wind speed. Altimeter wind speeds showed characteristic biases that they were higher (lower) than in-situ wind speeds at low (high) wind speed ranges. Some tendency was found that the difference between the maximum and minimum value gradually increased with distance from the buoy stations. For the improvement of the accuracy of altimeter wind speed, an equation for correction was derived based on the characteristics of errors. In addition, the significance of altimeter wind speed on the estimation of sea surface height was addressed by presenting the effect of the corrected wind speeds on the sea state bias values of Jason-1. 해상풍은 장기간동안 인공위성 산란계와 마이크로파 복사계를 주로 활용하여 관측되어왔다. 반면 위성 고도계 산출 풍속 자료의 중요성은 산란계의 탁월한 해상풍 관측 성능으로 인해 거의 부각되지 않았다. 인공위성 고도계 풍속 자료는 해수면고도를 산출하기 위한 해상상태편차(sea state bias) 보정항의 입력 자료로서 활용됨에 따라 높은 정확도가 요구된다. 본 연구에서는 인공위성 고도계(GFO, Jason-1, Envisat, Jason-2, Cryosat-2, SARAL) 풍속을 검증하고 오차 특성을 분석하기 위하여 이어도 해양과학기지와 마라도, 외연도 해양기상부이의 풍속 자료를 활용하여 2007년 12월부터 2016년 5월까지 총 1504개의 일치점 자료를 생성하였다. 해양실측 풍속에 대한 고도계 풍속은 1.59ms-1의 평균제곱근오차와 –0.35ms-1의 음의 편차를 보였다. 해양실측 풍속에 대한 고도계 해상풍 오차를 분석한 결과 고도계 해상풍은 풍속이 약할 때 과대추정되며 풍속이 강할 때 과소추정되는 특징을 보였다. 위성–실측 자료 간의 거리에 따른 고도계 풍속 오차를 분석한 결과 구간별 오차의 최댓값과 최솟값의 차는 거리에 따라 점차 증가하였다. 고도계 풍속의 정확도 향상을 위하여 분석된 오차 특성을 기반으로 보정식을 유도한 후 고도계 풍속을 보정하였다. 보정 전후의 풍속 자료를 활용하여 해상상태편차를 산출하였으며 Jason-1의 해상상태편차에 대한 해상풍 오차 보정의 영향을 확인하였다.

타워크레인의 작업 중지 풍속에 대한 현장 실태 조사 연구

이의주,신성우 한국안전학회 2018 한국안전학회지 Vol.33 No.1

Since tower cranes are susceptible to wind loads, the operation of the tower crane should be ceased when it exposed to a strong wind. For this reason, even in Korea, the operation limit for wind loading on the tower crane is regulated by a law. Recently the Korean law in which provided the wind speed limit to cease the tower crane operation has been revised from “instantaneous wind speed of 20 m/s” to “instantaneous wind speed of 15 m/s”. Although this revision is expected to reduce safety risks in tower crane operation, some field operators still insist to lower the wind speed limit. However, in many countries “wind speed of 20 m/s” is normally used as the maximum in-service wind speed for tower cranes. Therefore, the investigation of the proper wind speed for regulation would be helpful to secure the safety of the tower crane operation under windy condition. In this study the validity of the revised wind speed limit is investigated with the surveys targeted to both tower crane practitioners and parties of concerned in construction companies, in which various questions was provided for a suitable wind speed limit and the answers were analyzed. The results showed that the revised wind speed limit is acceptable to tower crane practitioners as well as the parties of concerned in construction companies and is satisfying the structural stability requirement for in-service state tower crane. Therefore, it can be concluded that the revised wind speed limit is valid in humanly safety point of view.

Adaptive maximum power point tracking control of wind turbine system based on wind speed estimation

Jong-Ho Hyun,Kyung-Youn Kim 한국전기전자학회 2018 전기전자학회논문지 Vol.22 No.2

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.

Adaptive maximum power point tracking control of wind turbine system based on wind speed estimation

Hyun, Jong-Ho,Kim, Kyung-Youn Institute of Korean Electrical and Electronics Eng 2018 전기전자학회논문지 Vol.22 No.2

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.