Downburst related damages in Brazilian buildings: Are they avoidable?

Loredo-Souza, Acir Mércio; Lima, Elias Galvan de; Vallis, Matthew Bruce; Rocha, Marcelo Maia; Wittwer, Adrián Roberto; Oliveira, Mário André Wanderley

doi:10.1016/j.jweia.2018.11.022

Cited by 22 publications

(11 citation statements)

References 18 publications

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“…Finally, the mean wind speed U(z, t) can be successfully obtained by substituting Equations ( 3) and (7) into Equation (2).…”

Section: Downburst Wind Fieldmentioning

confidence: 99%

“…Additionally, the vertical wind speed, usually neglected in the ABL wind field, has strong effects on the characteristics of the downburst wind field [4]. Surveys and statistics show that frequent and widespread downbursts, especially microbursts, have caused considerable damage to aviation industries and civil infrastructures in recent decades [5][6][7]. Downbursts can pose severe threats to structures located in their impact areas [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Downburst-Induced Vibration Coefficient of Long-Span Roof Structures

et al. 2022

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Long-span roof structures are vulnerable to being damaged by downbursts due to the sensitivity of such structures to wind loads. However, there is still no simple and practical method for the downburst-resistant design of such structures to date. Inspired by the wind-induced vibration coefficient (WVC) frequently used by engineers, this paper proposes a downburst-induced vibration coefficient (DVC) to evaluate the response of a roof structure subjected to downbursts. The proposed DVC is defined as the ratio of the total response to the mean response of the structure due to the action of downburst wind loads. The influences of different parameters on the downburst-induced vibration response of a long-span single-layer spherical reticulated structure are first analyzed in detail. Then, using a statistical approach, a design DVC, which can be practically adopted for civil engineers to evaluate the total structural response, is proposed to facilitate the structural downburst-resistant design. With the influences of different structural parameters fully taken into consideration, the design DVCs of displacement and internal force are studied through orthogonal analysis. Finally, regression models of the design DVCs are presented, and their reliability is verified via the application to a case study. The verification results indicate that the proposed regression models of the design DVCs are reliable and can be utilized to simply calculate the structural downburst-induced vibration response. The results obtained can serve as a reference for the downburst-resistant design of long-span roof structures.

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“…Finally, the mean wind speed U(z, t) can be successfully obtained by substituting Equations ( 3) and (7) into Equation (2).…”

Section: Downburst Wind Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Downburst-Induced Vibration Coefficient of Long-Span Roof Structures

et al. 2022

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“…This method is similar to what has been used by De Gaetano et al [40] who also used wind time series to classify different gust events. Other approaches focused on understanding storm types from a weather event perspective (e.g., considering specific individual case studies) while providing a detailed reconstruction of the meteorological conditions at the time of the event [3]. Yet another method is to investigate extreme events from a weather system topology perspective, similar to the work of Catto and Dowdy [41] who systematically linked compound hazards (extreme precipitations, winds and waves) to the associated weather system type using reanalysis and lightning observations.…”

Section: Generalised Pareto Distribution and Average Recurrence Intervalmentioning

confidence: 99%

“…They are defined in the Australian Bureau of Meteorology based on 3-second average values of wind speed. Strong wind gusts can cause significant structural damage, including the destruction of infrastructure such as power transmission lines, wind and solar farms and homes [1][2][3][4][5]. For example, more than 25,000 homes were without power across the city of Perth in Western Australia due to a strong storm with wind gusts of more than 100 kilometers per hour that knocked trees and branches onto power lines and caused damage across the city in October 2019 [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis and characterisation of extreme wind gust hazards in New South Wales, Australia

Rafei

Sherwood

Evans

et al. 2022

Preprint

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Extreme wind gusts cause major socioeconomic damage, and the rarity and localised nature of those events make their analysis challenging by either modelling or empirical approaches. Data from 29 automatic weather stations located in New South Wales (eastern Australia), with a maximum data range of 1998-2021, are used to study the distribution, frequency and average recurrence intervals (ARIs) of extreme gusts via a peaks-over-threshold approach. We distinguish between gust events generated by synoptic phenomena (e.g., cyclones and frontal systems), hereafter called ”synoptic events” and convective phenomena (i.e., thunderstorms), hereafter called ”convective events”, using the wind time series. For synoptic events the results show a gradient in the frequencies of gusts > 25 m/s that decreases when going inland from the coast, in contrast to the case for convective events which are more uniformly distributed geographically and have higher occurrence frequencies for extremes across nearly all inland locations. The ARI analysis shows that at inland locations extreme wind gusts are dominated by convective events, whereas coastal stations have similar frequencies of both types at low ARIs but again a dominance of convective events at the highest ARIs. Wind direction was also investigated and extreme gusts were found to be predominantly westerly at inland locations, with more variable direction for convective than synoptic events, and southerlies at coastal stations. This study confirms the dominant role of thunderstorms in producing the most extreme gusts in the region, and shows that wind risk varies strongly with distance from the coast.

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“…The availability of meteorological data indicating that the extreme winds not resulting from the worst aerodynamic direction could possibly justify the acceptance of the structural safety conditions. However, this procedure is only valid for strong winds from EPS storms (Loredo-Souza [28]), and can not be applied to strong winds from TS storms (Loredo-Souza et al [29] and [30]). Recent studies have shown that the highest wind speeds in Brazil are from TS storms (Vallis et al [31].…”

Section: Final Comments and Conclusionmentioning

confidence: 99%

Aerodynamic effects on a high slenderness concrete chimney

Loredo-Souza

Rocha

Oliveira³

et al. 2019

Rev. IBRACON Estrut. Mater.

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This is an open-access article distributed under the terms of the Creative Commons Attribution License A. M. LOREDO-SOUZA a acir@ufrgs.br https://orcid.org/0000-0002-6648-8315 M. M. ROCHA a mmrocha@ufrgs.br Abstract ResumoThis paper presents the results of a theoretical-experimental study on the aerodynamic behavior of a 150m high, slenderness 30, concrete chimney. For the wind tunnel tests two scaled models were built: one rigid for the measurement of the external pressures, and other aeroelastic, in which the main dynamic characteristics of the real structure were reproduced. The dynamic response under atmospheric turbulence (along-wind direction) is described in the paper and is compatible with the methodology of the Brazilian wind code NBR-6123. A brief analysis of the transversal response due to vortex shedding is presented according to the Canadian Wind Code NBCC. It is observed that, due to the low frequency of the structure, the dynamic approach leads to results significantly larger than those obtained from applying the conventional static approach of gust wind speed. The presence of the neighborhood have increased the loads on the structures.Este trabalho apresenta os resultados da determinação teórico-experimental do comportamento aerodinâmico de uma chaminé esbelta de concreto armado, com 150m de altura e esbeltez 30. Foram construídos dois modelos reduzidos: um rígido para medição das pressões e outro aeroelástico, reproduzindo as principais características dinâmicas da estrutura real. A resposta dinâmica à turbulência atmosférica é descrita no trabalho, compatível com a metodologia da NBR-6123. Também é apresentada uma análise da resposta transversal ao desprendimento de vórtices, segundo o método da Norma Canadense NBCC. Devido à baixa frequência fundamental da estrutura, o método dinâmico conduz a esforços significativamente maiores do que aqueles obtidos com o método estático convencional de velocidade de rajada. Observa-se também que a presença da vizinhança influenciou negativamente os resultados, majorando os esforços atuantes nas estruturas.Palavras-chave: vento, chaminés, resposta dinâmica, túnel de vento, modelagem aeroelástica.

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Downburst related damages in Brazilian buildings: Are they avoidable?

Cited by 22 publications

References 18 publications

Downburst-Induced Vibration Coefficient of Long-Span Roof Structures

Downburst-Induced Vibration Coefficient of Long-Span Roof Structures

Analysis and characterisation of extreme wind gust hazards in New South Wales, Australia

Aerodynamic effects on a high slenderness concrete chimney

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