平屋盖风荷载与等效静风荷载解析方法研究

发布时间：2018-11-01 16:06

【摘要】：大跨平屋盖结构是一种常见的屋盖形式,工程中应用广泛,风荷载是该类结构设计中的主要控制荷载之一。现行规范GB.50009中抗风设计条文给出的主要是针对高层、高耸等仅考虑第一阶振型的结构形式的风荷载计算方法,而对大跨平屋盖结构没有明确给出相关规定,已有研究主要采用参数化方法研究该类结构风振响应与等效静风荷载,但对地貌和平屋盖建筑形状的影响考虑不充分。本文选择三类地貌、三种长宽比平屋面模型,通过风洞实验研究屋面风荷载特性,旨在确定脉动风广义力谱的模型,同时在广义力的基础上推导等效静风荷载的解析公式,分析不同参数对等效静风荷载的影响规律。本文主要完成了以下几方面工作:(1)通过风洞实验系统研究了地貌、长宽比对平屋面风荷载特性:平均风压、脉动风压、极值风压、风压谱的影响,并分析了各荷载特性之间的联系。(2)研究不同地貌、建筑长宽比下屋面各点风压谱和广义力谱特征,与来流速压谱进行对比分析,并得到屋盖广义力谱的拟合公式。(3)利用广义力谱拟合公式和频域分析方法得到平板类平屋盖风振响应解析表达形式,并分析了地貌、建筑长宽比对共振响应和背景响应的影响。(4)根据结构风振响应特性,选择惯性力法推导得到等效静风荷载的解析公式,将其分为平均风压系数和等效静风荷载脉动风压系数两部分,研究地貌和建筑长宽比对等效静风荷载的影响,并给出了脉动等效风压系数峰值C的解析公式,工程应用时,可以根据C的解析公式快速准确地确定平屋盖的设计用风荷载标准值。
[Abstract]:Long-span flat roof structure is a common type of roof, which is widely used in engineering. Wind load is one of the main control loads in the design of this kind of structure. The wind-resistant design provisions in the current GB.50009 code mainly focus on the calculation method of wind load for high-rise buildings, such as tall buildings, which only consider the first order vibration modes, but there are no specific provisions for long-span flat roof structures. The parametric method is mainly used to study the wind-induced vibration response and equivalent static wind load of this kind of structures, but the influence of geomorphological and roof shapes is not fully considered. In this paper, three types of geomorphology and three kinds of aspect ratio roof models are selected to study the characteristics of roof wind load through wind tunnel experiments, in order to determine the model of generalized force spectrum of pulsating wind, and at the same time to derive the analytical formula of equivalent static wind load on the basis of generalized force. The influence of different parameters on the equivalent static wind load is analyzed. The main work of this paper is as follows: (1) the effects of geomorphology and aspect ratio on wind load characteristics of flat roof are studied by wind tunnel experiment: average wind pressure, pulsating wind pressure, extreme wind pressure, wind pressure spectrum. The relationship between load characteristics is analyzed. (2) the characteristics of wind pressure spectrum and generalized force spectrum at various points under different geomorphology and ratio of length to width of building are studied and compared with the pressure spectrum of coming velocity. The fitting formula of generalized force spectrum of roof is obtained. (3) using generalized force spectrum fitting formula and frequency domain analysis method, the analytical expression of flat roof wind-induced vibration response is obtained, and the geomorphology is analyzed. The influence of aspect ratio on resonance response and background response. (4) according to the characteristics of wind-induced vibration response of structure, the analytical formula of equivalent static wind load is derived by the inertial force method. It is divided into two parts: average wind pressure coefficient and equivalent static wind load pulsating wind pressure coefficient. The influence of geomorphology and building aspect ratio on equivalent static wind load is studied, and the analytical formula of peak value C of pulsating equivalent wind pressure coefficient is given. According to the analytical formula of C, the standard value of wind load for the design of flat roof can be determined quickly and accurately.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU312.1

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