低矮房屋風(fēng)荷載特性及近地面臺風(fēng)風(fēng)場應(yīng)用研究
發(fā)布時間：2018-12-08 18:09
【摘要】：本文基于低矮房屋臺風(fēng)實測系統(tǒng)獲得的實測數(shù)據(jù),詳細(xì)研究了臺風(fēng)登陸前后近地面風(fēng)特性,在風(fēng)洞試驗中模擬了臺風(fēng)風(fēng)場,分析了某實際工程在模擬臺風(fēng)風(fēng)場中的風(fēng)壓分布。另一方面,運(yùn)用現(xiàn)場實測和風(fēng)洞試驗相結(jié)合的方法研究了平坡屋面低矮房屋的風(fēng)壓特性和極值風(fēng)壓估計,探討了現(xiàn)有的極值估計方法在臺風(fēng)實測中的應(yīng)用,闡述了實測與風(fēng)洞試驗風(fēng)壓特性差異。通過進(jìn)一步模擬低矮房屋屋蓋角部突然破壞的風(fēng)洞試驗,分析了突然開孔的瞬時風(fēng)壓分布特征、內(nèi)壓頻譜特性及其傳播機(jī)理。本文的研究成果對臺風(fēng)多發(fā)地區(qū)的抗風(fēng)設(shè)計具有重要的意義。本文的主要結(jié)論如下:(1)臺風(fēng)“海鷗”登陸過程中,脈動風(fēng)向強(qiáng)度對順風(fēng)向和橫風(fēng)向湍流強(qiáng)度均有增強(qiáng)作用,橫風(fēng)向湍流強(qiáng)度隨著脈動風(fēng)向的增大呈近似線性增長。分析發(fā)現(xiàn)順風(fēng)向脈動風(fēng)速譜在低頻段與經(jīng)驗譜吻合較好。(2)根據(jù)某可開合大跨屋蓋結(jié)構(gòu)在臺風(fēng)風(fēng)場和常規(guī)風(fēng)場試驗結(jié)果分析,結(jié)果表明相同開啟狀態(tài)時,臺風(fēng)風(fēng)場下活動屋蓋的平均風(fēng)壓分布規(guī)律和B類風(fēng)場相似,屋蓋的開啟會減小屋蓋表面的平均風(fēng)壓。在臺風(fēng)風(fēng)場高湍流度作用下活動屋蓋更容易遭受不利極值風(fēng)荷載。此外,活動屋蓋的完全開啟對屋蓋的脈動風(fēng)壓系數(shù)影響顯著。(3)實測與試驗結(jié)果分析表明屋面角部測點實測平均風(fēng)壓大于風(fēng)洞試驗結(jié)果.對于屋面邊緣中部區(qū)域,垂直來流時,實測風(fēng)壓比試驗風(fēng)壓大約40%。實測風(fēng)壓非高斯性程度強(qiáng),處于負(fù)偏態(tài)和高峰態(tài)較多,相應(yīng)測點的試驗結(jié)果非高斯性程度弱,分析認(rèn)為三參數(shù)Gamma分布可以很好地描述低矮房屋風(fēng)壓概率分布特性。(4)通過誤差分析確定實測極值風(fēng)壓最佳觀測短時距是30s。根據(jù)峰值風(fēng)壓系數(shù)估計結(jié)果,發(fā)現(xiàn)現(xiàn)有的極值估計方法難以穩(wěn)定且精確地計算實測峰值風(fēng)壓,其中Sadek-Simiu法偏于保守,在無法準(zhǔn)確獲取峰值風(fēng)壓情況下,可采用該方法進(jìn)行估算�；赟adek-Simiu法的實測與試驗峰值風(fēng)壓系數(shù)結(jié)果對比,發(fā)現(xiàn)實測峰值風(fēng)壓絕對值相對試驗結(jié)果高20%~40%。(5)低矮房屋角部突然開孔時房屋內(nèi)部出現(xiàn)瞬時負(fù)壓,內(nèi)壓在開孔后0.05s趨于穩(wěn)定。脈動內(nèi)風(fēng)壓系數(shù)與來流湍流強(qiáng)度大小密切相關(guān),內(nèi)部區(qū)域風(fēng)壓相關(guān)程度高,可用一個測點代表內(nèi)壓時域特性。(6)湍流流場和均勻流場作用下內(nèi)壓相干函數(shù)曲線出現(xiàn)了不同數(shù)量的峰值,分析認(rèn)為可能是建筑振動、來流湍流、特征湍流造成的。在斜風(fēng)向下,屋蓋表面出現(xiàn)錐形渦,極易產(chǎn)生Helmholtz共振。當(dāng)不考慮阻尼作用,內(nèi)壓傳播方程中慣性系數(shù)C_I=1.6時,Helmholtz共振頻率理論值與試驗值基本相等。與墻面存在主開孔的研究結(jié)果對比,發(fā)現(xiàn)屋蓋角部存在一個開孔率約4.8%的方形孔時慣性系數(shù)值較大。
[Abstract]:Based on the measured data obtained from the low-rise house typhoon measurement system, the near-surface wind characteristics before and after the typhoon landing are studied in detail. The typhoon wind field is simulated in the wind tunnel test, and the wind pressure distribution of a practical project in the simulated typhoon wind field is analyzed. On the other hand, the wind pressure characteristics and extreme wind pressure estimation of low-rise roof with flat slope are studied by using the method of field measurement and wind tunnel test, and the application of existing extreme value estimation methods in typhoon measurement is discussed. The difference of wind pressure characteristics between measured and wind tunnel tests is expounded. Based on the wind tunnel test which simulates the sudden failure of the roof corner of the low housing, the instantaneous wind pressure distribution, the spectrum characteristics of the internal pressure and the propagation mechanism of the sudden opening are analyzed. The results of this paper are of great significance to the design of typhoon-prone areas. The main conclusions of this paper are as follows: (1) during the landing of Typhoon Seagull, the intensity of pulsating wind direction increases in both downwind and crosswind directions, and the intensity of crosswind turbulence increases approximately linearly with the increase of fluctuating wind direction. It is found that the spectrum of downwind pulsating wind velocity is in good agreement with the empirical spectrum at low frequency. (2) according to the experimental results of wind field and conventional wind field of a large span roof structure, the results show that the wind velocity spectrum is in the same open state. The average wind pressure distribution of moving roof under typhoon wind field is similar to that of B type wind field, and the opening of roof will reduce the average wind pressure on roof surface. The moving roof is more vulnerable to adverse extreme wind load under the action of high turbulence in typhoon wind field. In addition, the full opening of the moving roof has a significant effect on the fluctuating wind pressure coefficient of the roof. (3) the analysis of the measured and tested results shows that the measured mean wind pressure at the corner of the roof is greater than that of the wind tunnel test. For the middle part of roof edge, the measured wind pressure ratio is about 40. The non-Gao Si degree of measured wind pressure is strong, the negative skewness and peak state are more, and the test results of corresponding measuring points are weak. It is considered that the three-parameter Gamma distribution can well describe the probability distribution characteristics of wind pressure in low buildings. (4) through error analysis, the best observed short-time distance of measured extreme wind pressure is 30 s. According to the estimation results of the peak wind pressure coefficient, it is found that the existing extreme value estimation methods are difficult to calculate the measured peak wind pressure stably and accurately. The Sadek-Simiu method is conservative and can not accurately obtain the peak wind pressure. This method can be used to estimate. Based on the comparison of the measured and tested peak wind pressure coefficient by Sadek-Simiu method, it is found that the absolute value of the measured peak wind pressure is 20% 40% higher than the test result. (5) the instantaneous negative pressure appears in the house when the corner of the low building suddenly opens. The internal pressure tends to be stable at 0.05 s after opening. The wind pressure coefficient in the pulsating region is closely related to the turbulence intensity of the incoming flow, and the correlation degree of the wind pressure in the inner region is high. (6) there are different peaks in the coherent function curve of internal pressure under the action of turbulent flow field and uniform flow field, which may be caused by building vibration, flow turbulence and characteristic turbulence. Under the oblique wind direction, a cone vortex appears on the roof surface, which is easy to produce Helmholtz resonance. When damping is not considered and inertial coefficient C_I=1.6 in the equation of internal pressure propagation is not considered, the theoretical value of Helmholtz resonance frequency is basically equal to the experimental value. Compared with the research results of the main hole in the wall, it is found that there is a square hole with an opening ratio of about 4.8% at the corner of the roof.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU312.1
[Abstract]:Based on the measured data obtained from the low-rise house typhoon measurement system, the near-surface wind characteristics before and after the typhoon landing are studied in detail. The typhoon wind field is simulated in the wind tunnel test, and the wind pressure distribution of a practical project in the simulated typhoon wind field is analyzed. On the other hand, the wind pressure characteristics and extreme wind pressure estimation of low-rise roof with flat slope are studied by using the method of field measurement and wind tunnel test, and the application of existing extreme value estimation methods in typhoon measurement is discussed. The difference of wind pressure characteristics between measured and wind tunnel tests is expounded. Based on the wind tunnel test which simulates the sudden failure of the roof corner of the low housing, the instantaneous wind pressure distribution, the spectrum characteristics of the internal pressure and the propagation mechanism of the sudden opening are analyzed. The results of this paper are of great significance to the design of typhoon-prone areas. The main conclusions of this paper are as follows: (1) during the landing of Typhoon Seagull, the intensity of pulsating wind direction increases in both downwind and crosswind directions, and the intensity of crosswind turbulence increases approximately linearly with the increase of fluctuating wind direction. It is found that the spectrum of downwind pulsating wind velocity is in good agreement with the empirical spectrum at low frequency. (2) according to the experimental results of wind field and conventional wind field of a large span roof structure, the results show that the wind velocity spectrum is in the same open state. The average wind pressure distribution of moving roof under typhoon wind field is similar to that of B type wind field, and the opening of roof will reduce the average wind pressure on roof surface. The moving roof is more vulnerable to adverse extreme wind load under the action of high turbulence in typhoon wind field. In addition, the full opening of the moving roof has a significant effect on the fluctuating wind pressure coefficient of the roof. (3) the analysis of the measured and tested results shows that the measured mean wind pressure at the corner of the roof is greater than that of the wind tunnel test. For the middle part of roof edge, the measured wind pressure ratio is about 40. The non-Gao Si degree of measured wind pressure is strong, the negative skewness and peak state are more, and the test results of corresponding measuring points are weak. It is considered that the three-parameter Gamma distribution can well describe the probability distribution characteristics of wind pressure in low buildings. (4) through error analysis, the best observed short-time distance of measured extreme wind pressure is 30 s. According to the estimation results of the peak wind pressure coefficient, it is found that the existing extreme value estimation methods are difficult to calculate the measured peak wind pressure stably and accurately. The Sadek-Simiu method is conservative and can not accurately obtain the peak wind pressure. This method can be used to estimate. Based on the comparison of the measured and tested peak wind pressure coefficient by Sadek-Simiu method, it is found that the absolute value of the measured peak wind pressure is 20% 40% higher than the test result. (5) the instantaneous negative pressure appears in the house when the corner of the low building suddenly opens. The internal pressure tends to be stable at 0.05 s after opening. The wind pressure coefficient in the pulsating region is closely related to the turbulence intensity of the incoming flow, and the correlation degree of the wind pressure in the inner region is high. (6) there are different peaks in the coherent function curve of internal pressure under the action of turbulent flow field and uniform flow field, which may be caused by building vibration, flow turbulence and characteristic turbulence. Under the oblique wind direction, a cone vortex appears on the roof surface, which is easy to produce Helmholtz resonance. When damping is not considered and inertial coefficient C_I=1.6 in the equation of internal pressure propagation is not considered, the theoretical value of Helmholtz resonance frequency is basically equal to the experimental value. Compared with the research results of the main hole in the wall, it is found that there is a square hole with an opening ratio of about 4.8% at the corner of the roof.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU312.1
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