低矮建筑风沙荷载与大跨结构风振系数的研究

发布时间：2018-09-07 09:08

【摘要】：国内外的统计资料表明,在一切的自然灾害中,风灾造成的破坏和损失位居所有灾害之首。风灾可以分为三大类,一是飓风灾害;二是暴风灾害;三是由于雷暴天气以及龙卷风等引起的大风灾害。随着人类社会的发展,人类活动对全球气候变化的影响越来越大,风灾发生的强度和频率也在呈现增加的趋势。为此,本文针对风沙荷载和大跨屋盖结构风振系数进行了研究。目前,针对风沙现象和运动方面已经开展了一些研究,并取得了一系列的研究成果,发现风沙荷载对于建筑物的作用大于风荷载。但是,目前的主要研究手段多采用数值模拟的方法,鲜有建筑物风沙效应方面的试验研究。本文通过风洞测力试验,研究了不同沙浓度和风速条件下风沙对低矮建筑整体受力的影响。研究结果表明:和净风工况相比,风沙对低矮建筑整体受力有着较大影响。风沙对低矮建筑平均基底剪力系数有着明显的增大作用,且沙浓度越大,增大的越明显。而对于脉动基底剪力系数的影响,除了与沙浓度有关之外,还与指示风速有关。当风速较小时,风沙增大了试验房的脉动效应,而当风速较大时,风沙减小了试验房的脉动效应。根据对某体育馆进行风洞刚性模型测压试验所获得的数据,计算了该体育馆屋盖结构的风致响应及风振系数。进而研究了参与计算的振型数量对于风致响应和风振系数分析结果的影响,并且对比分析了考虑各振型交叉项的2:2法和不考虑振型交叉项的法以及多阶模态力法时的分析结果。经过分析,发现是否考虑高阶振型对体育馆屋盖结构的风致响应与风振系数的计算结果有一定的影响,而振型交叉项的影响也不可忽略。因此,本文提出了多阶模态力法的修正方法,考虑了振型交叉项的影响,得到了较好的结果。
[Abstract]:Statistics at home and abroad show that the damage and loss caused by wind disaster is the first of all natural disasters. Wind disaster can be divided into three categories, one is hurricane disaster, the other is storm disaster, and the third is gale disaster caused by thunderstorm weather and tornadoes. With the development of human society, the impact of human activities on global climate change is increasing, and the intensity and frequency of wind disasters are also increasing. Therefore, the wind-sand load and wind-induced vibration coefficient of long span roof structures are studied in this paper. At present, some researches have been carried out on the phenomenon and movement of wind and sand, and a series of research results have been obtained. It is found that the effect of wind and sand load on buildings is greater than that on wind load. However, most of the main research methods are numerical simulation, and there are few experimental studies on wind and sand effects of buildings. In this paper, the influence of wind and sand on the whole force of low buildings under different sand concentration and wind speed is studied by wind tunnel force measurement test. The results show that: compared with the clean wind condition, the wind sand has a great influence on the overall force of the low building. The wind sand has obvious effect on the average base shear coefficient of low buildings, and the bigger the sand concentration is, the more obvious the increase is. The influence of the shear coefficient of pulsating basement is not only related to the concentration of sand, but also to the indicated wind speed. When the wind speed is small, the wind sand increases the pulsation effect of the test room, but when the wind speed is high, the wind sand decreases the pulsation effect of the test room. The wind-induced response and wind-induced vibration coefficient of the roof structure of a gymnasium are calculated according to the data obtained from the wind tunnel rigid model pressure measurement test of a gymnasium. Furthermore, the influence of the number of modes involved in the calculation on the results of wind-induced response and wind-induced vibration coefficient analysis is studied, and the results of the 2:2 method, the method without considering the cross-terms of the modes and the multi-order modal force method are compared and analyzed. Through analysis, it is found that whether or not the higher-order modes have influence on the wind-induced response and the wind-induced vibration coefficient of the gymnasium roof structure, and the influence of the vibration mode cross term can not be ignored. Therefore, a modified method of multi-order modal force method is proposed in this paper, which takes into account the influence of the cross term of vibration mode, and the better results are obtained.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU312.1

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