• Title/Summary/Keyword: Gust

Search Result 238, Processing Time 0.026 seconds

Basic Data Advancement for Improving the Accuracy of Estimating the Damage Cost Caused by Strong Winds on the Korean Peninsula during Typhoon Periods (한반도 태풍시기 강풍유발 피해액 산정의 정확도 향상을 위한 기초자료의 고도화)

  • Yun, Hee-Seong;Jung, Woo-Sik
    • Journal of Environmental Science International
    • /
    • v.31 no.1
    • /
    • pp.87-97
    • /
    • 2022
  • In this study, type analysis was conducted along with the advancement of basic data to calculate the maximum damage caused by strong winds during the typhoon period. The result of the damage by region showed that in 2012, the difference in damage was clearly distinguished as the region was classified in detail. In addition, the result of the annual damage in 2011 was strong on the west coast, and in 2016, the damage to the southeast coast was significant. In 2012, the 3-second gust was relatively stronger on the west and southeast coasts than in 2011, and the winds blew stronger along the southeast coast in 2016. Monthly damage data showed that the damage to the west coast was high in August, and the damage to the southeast coast was high in October from 2002 to 2019. The 3-second gust showed the result of wide expansion throughout the southern coast of the Korean Peninsula in October. As a result, the damage differs for type bacause the intensities and paths of typhoons vary depending on their characteristics, the 3-second gust blows differently by region based on regional characteristics, and the sale price is considered in metropolitan cities.

Wind-induced dynamic response and its load estimation for structural frames of single-layer latticed domes with long spans

  • Uematsu, Yasushi;Sone, Takayuki;Yamada, Motohiko;Hongo, Takeshi
    • Wind and Structures
    • /
    • v.5 no.6
    • /
    • pp.543-562
    • /
    • 2002
  • The main purpose of this study is to discuss the design wind loads for the structural frames of single-layer latticed domes with long spans. First, wind pressures are measured simultaneously at many points on dome models in a wind tunnel. Then, the dynamic response of several models is analyzed in the time domain, using the pressure data obtained from the wind tunnel experiment. The nodal displacements and the resultant member stresses are computed at each time step. The results indicate that the dome's dynamic response is generally dominated by such vibration modes that contribute to the static response significantly. Furthermore, the dynamic response is found to be almost quasi-static. Then, a series of quasi-static analyses, in which the inertia and damping terms are neglected, is made for a wide range of the dome's geometry. Based on the results, a discussion is made of the design wind load. It is found that a gust effect factor approach can be used for the load estimation. Finally, an empirical formula for the gust effect factor and a simple model of the pressure coefficient distribution are provided.

Structural Optimization of a Joined-Wing Using Equivalent Static Loads (등가정하중을 이용한 접합날개의 구조최적설계)

  • Lee Hyun-Ah;Kim Yong-Il;Park Gyung-Jin;Kang Byung-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.30 no.5 s.248
    • /
    • pp.585-594
    • /
    • 2006
  • The joined-wing is a new concept of the airplane wing. The fore-wing and the aft-wing are joined together in a joined-wing. The range and loiter are longer than those of a conventional wing. The joined-wing can lead to increased aerodynamic performance and reduction of the structural weight. In this research, dynamic response optimization of a joined-wing is carried out by using equivalent static loads. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. The gust loads are considered as critical loading conditions and they dynamically act on the structure of the aircraft. It is difficult to identify the exact gust load profile. Therefore, the dynamic loads are assumed to be (1-cosine) function. Static response optimization is performed for the two cases. One uses the same design variable definition as dynamic response optimization. The other uses the thicknesses of all elements as design variables. The results are compared.

POD-based representation of the alongwind Equivalent Static Force for long-span bridges

  • Fiore, Alessandra;Monaco, Pietro
    • Wind and Structures
    • /
    • v.12 no.3
    • /
    • pp.239-257
    • /
    • 2009
  • This paper develops and discusses a method by which it is possible to evaluate the Equivalent Static Force (ESF) of wind in the case of long-span bridges. Attention is focused on the alongwind direction. The study herein carried out deals with the classical problems of determining the maximum effects due to the alongwind action and the corresponding ESFs. The mean value of the maximum alongwind displacement of the deck is firstly obtained both by the spectral analysis and the Gust Response Factor (GRF) technique. Successively, in order to derive the other wind-induced effects acting on the deck, the Gust Effect Factor (GEF) technique is extended to long-span bridges. By adopting the GRF technique, it is possible to define the ESF that applied on the structure produces the maximum alongwind displacement. Nevertheless the application of the ESF so obtained does not furnish the correct maximum values of other wind-induced effects acting on the deck such as bending moments or shears. Based on this observation, a new technique is proposed which allows to define an ESF able to simultaneously reproduce the maximum alongwind effects of the bridge deck. The proposed technique is based on the GEF and the POD techniques and represents a valid instrument of research for the understanding of the wind excitation mechanism.

Variation of Wind Field over the Leeward Area According to the Local-scale Geographical Variation under Strong Wind Condition (강풍조건에서 국지규모 지형 변화에 따른 풍하측 바람장 변화)

  • Jung, Woo-Sik;Park, Jong-Kil;Lee, Hwa Woon;Kim, Eun-Byul
    • Atmosphere
    • /
    • v.16 no.3
    • /
    • pp.169-185
    • /
    • 2006
  • We have investigated the wind speed variations over the leeward region when the strong wind blows. In this study we employ Envi-met numerical model to simulate the effect of surface boundary conditions. This model is applied for three cases which are characterized by land use and terrain height. The base case having natural geographical condition shows the weakest wind speed around lee side of Chunsudae. The others which remove the vegetation and cut off the terrain above 20 m ASL represent the stronger wind speed than base case. The main factor of this result is the surface friction. The distinct variation of wind is found at offshore area between Chunsudae and the southern part of village, but the northern part where is apart from Chunsudae shows a small variation of wind pattern. The weakening of wind speed around residential area is a maximum of 4~10 m/s when the wind blows in the village as strong as 55 m/s. The gust wind speed is weakened about 7~17 m/s in this case if the coefficient of gust wind adapted as 1.75.

Effects of viscoelastic memory on the buffeting response of tall buildings

  • Palmeri, A.;Ricciardelli, F.;Muscolino, G.;De Luca, A.
    • Wind and Structures
    • /
    • v.7 no.2
    • /
    • pp.89-106
    • /
    • 2004
  • The response of tall buildings to gust buffeting is usually evaluated assuming that the structural damping is of a viscous nature. In addition, when dampers are incorporated in the design to mitigate the response, their effect is allowed for increasing the building modal damping ratios by a quantity corresponding to the additional energy dissipation arising from the presence of the devices. Even though straightforward, this procedure has some degree of inaccuracy due to the existence of a memory effect, associated with the damping mechanism, which is neglected by a viscous model. In this paper a more realistic viscoelastic model is used to evaluate the response to gust buffeting of tall buildings provided with energy dissipation devices. Both cases of viscous and hysteretic inherent damping are considered, while for the dampers a generic viscoelastic behaviour is assumed. The Laguerre Polynomial Approximation is used to write the equations of motion and find the frequency response functions. The procedure is applied to a 25-story building to quantify the memory effects, and the inaccuracy arising when the latter is neglected.

A Study on the Ballast-flying Phenomena by Strong Wind Induced by High-speed Train (열차풍에 의한 고속선 자갈비산현상 연구)

  • Kwon Hyeok-Bin;Park Choon-Soo
    • Journal of the Korean Society for Railway
    • /
    • v.8 no.1
    • /
    • pp.6-14
    • /
    • 2005
  • The mechanism of ballast-flying phenomena by strong wind induced by high-speed trains has extensively been investigated by conducting wind tunnel test and field-measuring of wind velocity in the vicinity of the track. The ballast gathered from the Seoul-Busan high-speed railway track has been classified by mass and shape to find relationship between those properties and the characteristic of movement in high wind and 16-channel Kiel-probe array has been used to examine the detailed flow structure above the surface of the track. The probability of ballast-flying during the passage of the high-speed train has been assessed comparing the results from wind tunnel test and that from field-measuring. The results shows that when the G7 train runs well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability far small ballast under 50g to fly is about 50% when it is on the tie. If the G7 train runs at 350km/h, the wind gust just above the tie increases to 30m/s, therefore radical countermeasure seems to be needed.

Characteristics of Zonda wind in South American Andes

  • Loredo-Souza, Acir M.;Wittwer, Adrian R.;Castro, Hugo G.;Vallis, Matthew B.
    • Wind and Structures
    • /
    • v.24 no.6
    • /
    • pp.657-677
    • /
    • 2017
  • This paper discusses some features and conditions that characterize the Zonda wind, focusing particularly on the implications for wind engineering applications. This kind of wind, typical of mountainous regions, is far from being adequately characterized for computational simulations and proper modeling in experimental facilities such as boundary layer wind tunnels. The objective of this article is to report the research works that are being developed on this kind of wind, describing the main obtained results, and also to establish some general guidelines for the proper analysis of the Zonda in the wind engineering context. A classification for the Zonda wind is indicated and different cases of structural and environmental effects are described. Available meteorological data is analyzed from the wind engineering point of view to obtain the Zonda wind gust factors, as well as basic wind speeds relevant for structural design. Some considerations and possible directions for the Zonda wind-tunnel and computational modeling are provided. Gust factor values larger than those used for open terrain were obtained, nevertheless, the basic wind speed values obtained are similar to values presented by the Argentinian Wind Code for three-second gust, principally at Mendoza airport.

Comparative assessment of ASCE 7-16 and KBC 2016 for determination of design wind loads for tall buildings

  • Alinejad, Hamidreza;Jeong, Seung Yong;Kang, Thomas H.K.
    • Wind and Structures
    • /
    • v.31 no.6
    • /
    • pp.575-591
    • /
    • 2020
  • Wind load is typically considered as one of the governing design loads acting on a structure. Understanding its nature is essential in evaluation of its action on the structure. Many codes and standards are founded on state of the art knowledge and include step by step procedures to calculate wind loads for various types of structures. One of the most accepted means for calculating wind load is using Gust Load Factor or base bending Moment Gust Load Factor (MGLF), where codes are adjusted based on local data available. Although local data may differ, the general procedure is the same. In this paper, ASCE 7-16 (2017), which is used as the main reference in the U.S., and Korean Building Code (KBC 2016) are compared in evaluation of wind loads. The primary purpose of this paper is to provide insight on each code from a structural engineering perspective. Herein, discussion focuses on where the two codes are compatible and differ. In evaluating the action of wind loads on a building, knowledge of the dynamic properties of the structure is critical. For this study, the design of four figurative high-rise buildings with dual systems was analyzed.

The Effect of the Gust of Wind on Safety of Driving Vehicles in Higher Speed Freeways (강한 바람이 고속도로 차량 주행 안전성에 미치는 영향 분석)

  • Kim, Sang-Youp;Choi, Jai-Sung;Hwang, Kyung-Sung;Hwang, Kyung-Soo
    • International Journal of Highway Engineering
    • /
    • v.11 no.2
    • /
    • pp.45-54
    • /
    • 2009
  • Despite vehicle instability problems caused by gusts of wind on freeways located in mountain or seaside areas, current national highway design standards overlook their detrimental effects, and if higher design speed freeways being proposed now by the government are in operation, the strong effect of the gust of wind becomes a highway alignment design issue. This paper presents the vehicle movements and their resulting safety effects by checking vehicle sliding and overturn based on vehicle dynamic analysis for the case when a gust of wind blows to vehicles negotiating curves on higher speed freeways. In this analysis, vehicle types, curve radii, motorist responsive time to vehicle driving path changes, and vehicle speeds are systematically arranged to get vehicle sliding and overturn values in each different conditions. The results showed that there were little overturn possibilities when wind speed would stay in 50m/sec with higher than 600 meter curve radii. Interestingly it was also found in sliding checks that, although being safe at less than 15.0m/sec wind speed levels, there appeared the need of vehicle travel prohibitions when the wind speed could exceed 25.0m/sec level. The findings in this research is of information in future higher speed freeway designs, and particularly useful when designing freeways passing frequent gust wind areas.

  • PDF