L자형 평면 건축물의 비정형성을 고려한 풍하중 할증계수의 제안

류혜진,조현주,하영철 한국풍공학회 2020 한국풍공학회지 Vol.24 No.1

비정형 형태의 건축물에서 발생하는 풍하중은 KBC-2016의 풍하중 산정식으로 산정할 수 없기 때문에 풍동실험을 통해 풍하 중을 평가할 수밖에 없다. KBC-2016으로 비정형건축물을 정형적인 건축물로 가정하여 풍하중을 평가한다면 과소평가될 우려가 있 다. 그러므로 보다 합리적인 평가를 위해 풍하중을 할증시켜줄 필요가 있다. 본 연구에서는 평면형태가 L자인 건축물을 대상으로 풍력 실험을 실시하여 풍하중을 산정하였으며, 이를 KBC-2016으로 산정한 풍하중과 비교하였다. 풍동실험을 통해 구한 L자형 건축물의 풍 하중과 KBC-2016으로 L자형 건축물과 동일한 폭과 깊이를 가진 사각형평면 건축물을 대상으로 구한 풍하중의 비로 풍하중 할증계수 를 도출하였다. 풍하중 할증계수는 1.6~2.2로 나타났다. KBC-2016에 의해 평가한 사각형 건축물의 풍하중에 풍하중 할증계수를 곱하 면 L자형 건축물의 풍하중이 된다. Wind loads generated from irregular buildings can't be evaluated by KBC-2016, so wind loads should be evaluated by wind tunnel test. If the wind load is evaluated using KBC-2016, which assumes irregular buildings as regular buildings, it may be underestimated. Therefore the wind loads need to be increased for more reasonable evaluation. In this study, wind loads was evaluated by wind tunnel test on L-shaped buildings and compared with wind loads evaluated by KBC-2016. The amplification factor on wind load was derived from the ratio of wind loads by wind tunnel tests on L-shaped building to wind loads by KBC-2016 on rectangular building. The amplification factor ranged from 1.6 to 2.2. The wind load of a rectangular building evaluated by KBC-2016 is multiplied by the amplification factor to become the wind load of an L-shaped building.

Y자형 건축물의 풍하중 증감계수의 제안

신동현,류혜진,이규익,하영철 한국풍공학회 2023 한국풍공학회지 Vol.27 No.3

KDS 41 12 00의 풍하중 관련 식은 정형적인 건축물에 대한 수많은 연구를 통해 만든 경험식이다. 따라서 비정형 건축물에 대하여 KDS 41 12 00에 따라 풍하중을 산출하면 건축물의 형상이 반영되지 않아 실제 풍하중과 상이할 수 있다. 이에 Y자형 건축물에 대하여 풍동실험에 따른 풍하중과 KDS 41 12 00에 따른 풍하중을 산출하고 비교하고자 하였다. 이를 위해 풍력실험을 수행하였고 최종적으로 두 가지 방법에 따른 풍하중의 비율을 산출하고 이를 풍하중 증감계수로 도출하고자 하였다. 본 연구에서 제시하는 풍하중 증감계수를 KDS 41 12 00에 따라 풍하중 산출 과정에 적용한다면 보다 합리적으로 Y자형 건축물에 대한 풍하중을 산출할 수 있을 것으로 사료된다. The equations related wind load in KDS 41 10 15 are the empirical formula developed through numerous studies on regular buildings. Therefore, when wind load is calculated according to KDS 41 12 00 for an irregular shaped building, the shape of the building is not reflected and it may differ from the actual wind load. Accordingly, the wind load according to the wind tunnel test and the wind load according to KDS 41 12 00 were calculated and compared for the Y-shaped building. To this end, a high frequency force balance was conducted, and finally, the ratio of wind loads according to the two methods was calculated and the increasing and decreasing coefficients for wind load were derived. If the increasing and decreasing coefficients for wind load presented in this study are applied to the wind load calculation process in accordance with KDS 41 12 00, it is considered that the wind load for Y-shaped buildings can be calculated more reasonably.

멱법칙 기반의 풍하중과 건축구조기준의 고도분포계수(Kzr)를 이용한 풍하중의 비교분석

김예준,조영민 한국전산유체공학회 2023 한국전산유체공학회지 Vol.28 No.3

Wind load is an essential consideration in all building design. It refers to the force of the wind on the building and is a crucial factor in determining the strength and stability of the structure. There are several reasons why it is important to set wind load for calculating building wind. Firstly, wind load is one of the significant loads that a building must withstand. Resistance to wind load is essential to prevent structural damage during high wind events such as storms, hurricanes, and tornadoes. By setting wind load, engineers can determine the wind pressure that the building will experience and design the structure accordingly. Secondly, wind load affects the performance and energy efficiency of the building. The front of the building is typically the primary obstacle to wind load and can have a significant impact on the building's energy consumption. By setting wind load, designers can optimize the building's appearance to minimize energy consumption and improve the building's performance. In this study, we compared and analyzed wind loads calculated using the power law method and the altitude distribution coefficient of wind speed (Kzr) that varies depending on the surface condition. Through this comparison, we were able to analyze the differences in the wake resulting from wind load settings and determine the wind load settings according to the ground environment.

변동풍력의 연직분포를 고려한 건축물의 풍하중 평가

류혜진(Ryu, Hye-Jin),신동현(Shin, Dong-Hyeon),하영철(Ha, Young-Cheol) 대한건축학회 2019 大韓建築學會論文集 : 構造系 Vol.35 No.7

The wind tunnel test makes it possible to predict the wind loads for the wind resistant design. There are many methods to evaluate wind loads from data obtained from the wind tunnel test and these methods have advantages and disadvantages. In this study, two of these methods were analyzed and compared. One is the wind load evaluation method by fluctuating displacement and the other is the wind load evaluation method considering vertical profile of fluctuating wind force. The former method is evaluated as the sum of the mean wind load of the average wind force and the maximum value of the fluctuating wind load. The latter method is evaluated as the sum of the mean wind load and maximum value of the background wind load, and the maximum value of the resonant wind load. Two methods were applied to the wind tunnel test to compare the evaluated wind loads according to the two methods, with a maximum difference of about 1.2 times. The wind load evaluated by the method considering vertical profile of the fluctuating wind force (VPFWF) was larger than the wind load evaluated by the method by fluctuating displacement (FD). Especially, the difference of the wind load according to the two methods is large in the lower part of the building and the wind load is reversed at a specific height of the building. VPFWF of evaluating resonant wind loads and background wind loads separately is more reasonable.

국내외 풍직각방향 및 비틀림 풍하중 기준 비교 연구

강현구,정승용,하미드레자 한국풍공학회 2019 한국풍공학회지 Vol.23 No.3

이 연구에서는 국내 설계기준인 KBC 2016, 미국 기준 ASCE 7-16, 국제 표준 ISO 4354:2012의 풍직각방향 및 비틀림 풍하중을 비교 분석하였다. 고층건물 설계를 위한 상세 산정식과 그 적용 기준, 풍하중 하중조합 등을 비교하였다. KBC는 ISO와 유사한 유도과정을 가지지만, 풍직각방향 풍하중 산정 시 사용된 풍동실험 데이터의 차이로 인해, 변장비가 큰 경우 와류 재부착에 의한 파워스펙트럼의 2차 피크를 ISO가 약간 크게 산정하고 구조물과의 공진으로 인해 ISO가 하중을 60% 정도 크게 산정한다. KBC와 ISO의 고층건물에서의 비틀림 풍하중은 동일하다. ASCE는 고층건물을 위한 상세식을 제시하지 않지만, 중저층 건물에서는 풍방향 하중에 비례하는 하중조합 형태로 반영한다. KBC와 ISO에서도 ASCE 처럼 중저층 건물에서 편심에 의한 비틀림 풍하중을 반영할 필요가 있다. In this study, across- and torsional-wind loads of KBC 2016, ASCE 7-16, and ISO 4354:2012 are compared. The detailed calculation procedures for high-rise building and its application criteria, and load combinations are compared. KBC and ISO have similar procedures, but the 2nd peak of power spectral density by ISO is larger than that by KBC due to the difference of use of experimental results. It results in large differences of the loads due to the resonant. The torsional-wind loads of ISO and KBC are identical. ASCE does not provide detailed formula of across- and torsional-wind loads for high-rise buildings, but they are included in the load combinations for low-to-mid-rise buildings with the forms proportional to the along-wind load. In KBC and ISO, it is also necessary to adopt the torsional wind load in low-to-mid-rise buildings caused by the eccentricity, as in ASCE.

KBC 2016 풍하중의 산정법 이해 및 고층건물에서의 적용

강현구,정승용,하미드레자 한국풍공학회 2019 한국풍공학회지 Vol.23 No.2

이 연구에서는 KBC 2016 풍하중의 산정 배경을 구체적으로 설명하고, 콘크리트 이중골조 고층건물에서의 풍하중과 지진하중을 비교하였다. 풍하중은 평균성분, 비공진성분, 공진성분으로 구성되며, 건물이 고층화될수록 공진성분이 우세해진다. 구조물의 형 상비가 3보다 큰 경우 풍직각방향 및 비틀림 하중을 고려하며, 풍방향하중과 설계지진하중보다 풍직각방향 풍하중이 지배적이게 된다. In this study, a detailed background of wind load determination according to KBC 2016 and its application to high-rise concrete buildings with dual system are presented. The wind load consists of mean, background, and resonant components. As a building becomes higher, the resonant component dominates the wind load. When the aspect ratio exceeds 3, across-wind and torsional wind loads are considered. The across-wind loads to buildings with aspect ratio exceeding 3 become larger than along-wind loads and seismic loads.

강도설계용 풍하중 평가를 위한 재현기간과 기본풍속지도의 제안

하영철(Ha, Young-Cheol) 대한건축학회 2018 大韓建築學會論文集 : 構造系 Vol.34 No.2

Strength design wind loads for the wind resistance design of structures shall be evaluated by the product of wind loads calculated based on the basic wind speed with 100 years return period and the wind load factor 1.3 specified in the provisions of load combinations in Korean Building Code (KBC) 2016. It may be sure that the wind load factor 1.3 in KBC(2016) had not been determined by probabilistic method or empirical method using meteorological wind speed data in Korea. In this paper, wind load factors were evaluated by probabilistic method and empirical method. The annual maximum 10 minutes mean wind speed data at 69 meteorological stations during past 40 years from 1973 to 2012 were selected for this evaluation. From the comparison of the results of those two method, it can be found that the mean values of wind load factors calculated both probability based method and empirical based method were similar at all meteorological stations. When target level of reliability index is set up 2.5, the mean value of wind load factors for all regions should be presented about 1.35. When target level of reliability index is set up 3.0, wind load factor should be presented about 1.46. By using the relationship between importance factor(conversion factor for return period) and wind load factor, the return periods for strength design were estimated and expected wind speeds of all regions accounting for strength design were proposed. It can be found that return period to estimate wind loads for strength design should be 500 years and 800 years in according to target level of reliability index 2.5 and 3.0, respectively. The 500 years basic wind speed map for strength design was suggested and it can be used with a wind load factor 1.0.

폭이 넓은 주변건물에 의한 풍하중 상호간섭효과

홍성일,조강표,김윤석 한국풍공학회 2004 한국풍공학회지 Vol.8 No.2

우리나라 풍하중 기준인 “건축물 하중기준 및 해설(2000)”은 노풍도를 고려해서 건물이 단독으로 서 있는 경우를 상정하여 풍동실험을 수행함으로써 얻어진 결과에 근거한다. 그러나 주변건물에 의해 둘러싸인 실제의 경우에서는 건물에 작용하는 풍하중은 건물이 단독으로 서 있을 경우와는 기류의 변동으로 인해 상당히 다르게 나타날 수 있다. 이와 같은 고층건물의 풍하중 상호간섭효과에 영향을 미칠 수 있는 요소 즉, 풍상측 지형, 건물의 기학적 형상, 풍속 및 풍향 과 건물의 상대배치 중에서 건물의 상대배치는 상호간섭효과에 가장 큰 영향을 줄 수 있다. 본 연구에서는 정사각형 평면형상을 갖고 있는 초고층 건축물이 2.5의 변장비를 가진 주변 건물의 배치간격에 따라 초고층 건축물이 어떤 하중영향을 받는지를 조사하였다. 풍하중 상호간섭효과는 고주파 천평모형을 이용하여 풍동실험을 통해서 수행되었다. 풍하중 상호간섭효과는 초고층 건축물 주변에 다른 건축물이 있는 경우의 풍하중과 초고층 건축물 단독으로 있을 경우의 풍하중과의 비로 나타냈다. The evaluation of wind loads on buildings in Korea is carried out mainly by using Korean Standard Design Loads for Buildings, whose specifications are generally based on wind-tunnel tests performed on isolated structures considering wind exposure. However, it has been shown that wind loads on buildings in realistic environments surrounded by neighboring buildings may be considerably different from those measured on isolated buildings. Wind-induced interference effects depend mainly on the geometry and arrangement of these structures, their orientation and upstream terrain conditions. The most important factor among them is the arrangement of building structures. It is examined in this study that how wind loads on a high-rise building with square section are affected by the arrangement of neighboring building with side ratio of 2.5 to measured building. Wind-induced interference effects on high-rise buildings were performed by wind-tunnel tests of force balance model. Interference factor was defined as ratio of wind force on a building with interfering buildings present to wind force on an isolated building.

건물의 상호배치에 따른 풍하중 영향평가에 관한 연구

조강표,김윤석,홍성일 한국풍공학회 2004 한국풍공학회지 Vol.8 No.1

우리나라 풍하중 기준인 “건축물 하중기준 및 해설(2000)”은 노풍도를 고려해서 건물이 단독으로 서 있는 경우를 상정하여 풍동실험을 수행함으로써 얻어진 결과에 근거한다. 그러나 주변건물에 의해 둘러싸인 실제의 경우에서는 건물에 작용하는 풍하중은 건물이 단독으로 서 있을 경우와는 기류의 변동으로 인해 상당히 다르게 나타날 수 있다. 이와 같은 고층건물의 풍하중 상호간섭효과에 영향을 미칠 수 있는 요소 즉, 풍상측 지형, 건물의 기학적 형상, 풍속 및 풍향 과 건물의 상대배치 중에서 건물의 상대배치는 상호간섭효과에 가장 큰 영향을 줄 수 있다. 본 연구에서는 정사각형 평면형상을 갖고 있는 초고층 건축물이 똑 같은 크기의 주변 건물의 배치간격에 따라 초고층 건축물이 어떤 하중영향을 받는지를 조사하였다. 풍하중 상호간섭효과는 고주파 천평모형을 이용하여 풍동실험을 통해서 수행되었다. 풍하중 상호간섭효과는 초고층 건축물 주변에 다른 건축물이 있는 경우의 풍하중과 초고층 건축물 단독으로 있을 경우의 풍하중과의 비로 나타냈다. The evaluation of wind loads on buildings in Korea is carried out mainly by using Korean Standard Design Loads for Buildings, whose specifications are generally based on wind-tunnel tests performed on isolated structures considering wind exposure. However, it has been shown that wind loads on buildings in realistic environments surrounded by neighboring buildings may be considerably different from those measured on isolated buildings. Wind-induced interference effects depend mainly on the geometry and arrangement of these structures, their orientation and upstream terrain conditions. The most important factor among them is the arrangement of building structures. It is examined in this study that how wind loads on a high-rise building with square section are affected by the arrangement of neighboring building. The neighboring building is the same size as the measured building. Wind-induced interference effects on high-rise buildings were performed by wind-tunnel tests of force balance model. Interference factor was defined as ratio of wind force on a building with interfering buildings present to wind force on an isolated building.

풍속 분포곡선이 어선의 풍하중에 미치는 영향에 관한 연구

이상의 해양환경안전학회 2020 해양환경안전학회지 Vol.26 No.7

지난 10년간 복원력 상실에 의한 어선의 해양사고가 지속해서 증가하고 있으며, 갑작스러운 강풍이 주요 원인으로 지적되고 있다. 이러한 강풍에도 견딜 수 있는 어선의 운동·조종성능을 확보하기 위해서는 정밀한 풍하중 예측 기법이 우선되어야 한다. 따라서 본 연구에서는 전산유체역학 기법을 이용한 어선의 풍하중 평가기법을 개발하고자 한다. 특히, 고도 변화에 따라 풍속이 변화하는 계산환경을 모사하여 그 결과를 균일한 속도분포를 가정한 수치해석 결과와 비교 분석하고자 한다. 본 연구에서는 0-180°까지 15° 간격으로 13개의 방향에 대해 풍하중을 계산하였으며, 계산에 사용된 메쉬 모델은 메쉬 의존성 시험을 수행하여 개발하였다. 전산수치해석은 RANS(Reynolds-averaged Navier-Stokes) 기반 상용 해석 Solver인 STAR-CCM+(Ver. 13.06)와 k-ω 난류 모델을 이용하여 정상상태(Steady State) 유동해석을 수행하였다. 수치해석결과를 간략히 살펴보면 Surge, Sway 및 Heave에서 39.5%, 41.6% 및 46.1% 풍하중이 감소하였으며 Roll, Pitch 및 Yaw에서 48.2%, 50.6% 및 36.5% 감소하였다. 결론적으로 본 연구에서는 고도에 따른 풍속 변화 모델을 통해 기존보다 정밀한 수준의 풍하중 추정이 가능한 것을 확인하였으며, 그 결과가 선박의 풍하중 추정 평가기법 발전에 이바지하길 기대한다. Marine accidents involving fishing boats, caused by a loss of stability, have been increasing over the last decade. One of the main reasons for these accidents is a sudden wind attacks. In this regard, the wind loads acting on the ship hull need to be estimated accurately for safety assessments of the motion and maneuverability of the ship. Therefore, this study aims to develop a computational model for the inlet boundary condition and to numerically estimate the wind load acting on a fishing boat. In particular, wind loads acting on a fishing boat at the wind speed profile boundary condition were compared with the numerical results obtained under uniform wind speed. The wind loads were estimated at intervals of 15° over the range of 0° to 180°, and i.e., a total of 13 cases. Furthermore, a numerical mesh model was developed based on the results of the mesh dependency test. The numerical analysis was performed using the RANS-based commercial solver STAR-CCM+ (ver. 13.06) with the k-ω turbulent model in the steady state. The wind loads for surge, sway, and heave motions were reduced by 39.5%, 41.6%, and 46.1% and roll, pitch, and yaw motions were 48.2%, 50.6%, and 36.5%, respectively, as compared with the values under uniform wind speed. It was confirmed that the developed inlet boundary condition describing the wind speed gradient with respect to height features higher accuracy than the boundary condition of uniform wind speed. The insights obtained in this study can be useful for the development of a numerical computation method for ships.