局部开洞的落地四坡房屋表面风压分布研究

发布时间：2019-06-06 13:05

【摘要】：落地四坡房屋具有搭拆简易、携带方便、可重复利用及对场地条件要求低等优势,因而被广泛应用于民用及军事领域。落地四坡房屋因质量轻、刚度及阻尼小、处于大气边界层中风速变化大和湍流度高的近地区域,属于典型的风敏感低矮建筑。由于房屋的使用功能如通风、采光及人流通行等因素,需要对房屋进行开门和窗等洞口,或者因某些外力因素导致局部围护系统和屋盖系统的损坏形成破坏性洞口,此时风压分布发生显著变化,房屋所受风荷载由内、外荷载共同作用。而我国荷载规范(GB50009-2012)仅涉及开洞双坡屋面房屋的风压系数,开洞与封闭双坡屋面房屋的屋盖体型系数比值可达2.6,两者房屋表面风压差异显著;国内外相关规范对于如落地四坡房屋等复杂体型的风压均无相关规定,致使围护构件及整体结构的风荷载计算无据可依,因此亟需对不同开洞布置的落地四坡房屋进行风致响应研究,为类似房屋提供设计理论依据。本文基于流体动力学和大气边界层基本理论,运用FLUENT软件并借助经典开洞TTU标准模型的现场实测试验数据,探讨与分析数值风洞尺寸、网格划分技术、湍流模型、离散格式及求解算法等关键技术及参数,建立单面、双面、三面及四面开洞落地四坡房屋的数值风洞。以来流风向、洞口大小、洞口位置及洞口形状为分析参数,运用数值风洞对104种开洞房屋工况进行表面风压分布特性数值模拟,得到各分区的风压分布。在此基础上,分析总结来流风向、洞口大小、洞口位置、洞口形状及单面、多面开洞对房屋表面风压分布的影响规律,并提出可供围护构件及整体结构抗风设计的风荷载体型系数。结果表明:开洞对落地四坡房屋风压分布影响显著,迎风面单面开洞时最为不利,屋盖的风压系数峰值高达-1.24,设计及使用时应引起足够的重视。
[Abstract]:The landing four-slope house is widely used in civil and military fields because of its advantages of simple demolition, easy to carry, reusable and low requirements for site conditions. The four-slope building is a typical wind-sensitive low-rise building because of its light weight, low stiffness and damping, and is located in the near-ground area with large wind speed change and high turbulence in the atmospheric boundary layer. Because of the use function of the house, such as ventilation, lighting and the flow of people, it is necessary to open doors and windows of the house, or because of some external force factors, the damage of the local enclosure system and the roof system results in the damage of the local enclosure system and the roof system to form a destructive opening. At this time, the wind pressure distribution changes significantly, and the wind load on the building is acted on by the internal and external loads. However, the load code of our country (GB50009-2012) only deals with the wind pressure coefficient of open double slope roof house, and the ratio of roof shape coefficient between open hole and closed double slope roof house can reach 2.6, and there is significant difference between the two houses in surface wind pressure. The relevant codes at home and abroad have no relevant provisions for the wind pressure of complex bodies, such as four-slope buildings, which makes the wind load calculation of enclosure members and the whole structure unsupported. Therefore, it is urgent to study the wind-induced response of four-slope buildings with different opening arrangements, so as to provide a theoretical basis for the design of similar buildings. Based on the basic theory of fluid dynamics and atmospheric boundary layer, this paper discusses and analyzes the numerical wind tunnel size, grid division technology and turbulence model by using FLUENT software and with the help of the field test data of the classical open hole TTU standard model. The numerical wind tunnel of one-sided, double-sided, three-sided and four-sided open-hole four-slope buildings is established by discrete scheme and solving algorithm. Since the wind direction, the size of the entrance, the position of the entrance and the shape of the opening are used as the analysis parameters, the surface wind pressure distribution characteristics of 104 kinds of open-hole houses are simulated by numerical wind tunnel, and the wind pressure distribution of each partition is obtained. On this basis, the influence of the incoming wind direction, the size of the entrance, the position of the entrance, the shape of the entrance and the one-sided and multi-side holes on the wind pressure distribution on the surface of the house is analyzed and summarized. The wind load carrier type coefficient which can be used for the wind resistance design of enclosure members and the whole structure is put forward. The results show that the opening has a significant effect on the wind pressure distribution of the four-slope building, and the wind pressure coefficient of the roof is as high as-1.24 when opening holes on one side of the upwind surface. Enough attention should be paid to the design and use of the roof.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU312.1

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