L型截面高层建筑风荷载特性及其优化设计研究

发布时间：2018-02-17 03:10

本文关键词： 高层建筑风洞试验风压分布风荷载风致响应数学模型相干函数优化设计　出处：《湖南大学》2015年博士论文　论文类型：学位论文

【摘要】：随着科学技术水平的发展和城市用地的日益紧张，高层建筑物逐渐向更高、更轻、更柔的趋势发展，高层建筑物的体型也更加复杂。作为高层建筑结构设计和幕墙设计的控制性因素，风荷载及其结构优化设计是超高层建筑结构设计不可忽视的重要问题。然而，现有的风荷载研究主要针对方形或矩形截面高层建筑物，对于平面不规则高层建筑物的研究相对匮乏。本文首先以某L型截面高层建筑的工程案例为研究背景，对其表面风压分布及风荷载特性进行了分析；为进一步得到具有普适性的规律，对一系列L型截面高层建筑开展了不同工况的刚性模型风洞试验研究，并基于试验结果对L型截面高层建筑的风荷载特性进行了深入的研究；最后，利用最优准则法对L型截面高层建筑的风荷载进行了优化设计研究。主要的研究工作包括：对CAARC高层建筑标准模型分别开展了刚性模型测压试验和高频动态天平测力试验研究。给出了测压试验管路频响函数的修正方法和风压时程采集信号的平滑处理方法。通过与不同风洞研究机构的试验结果进行比较，验证了湖南大学建筑与环境风洞试验室的试验设备、流场模拟、数据采集及处理技术的可靠性。同时，结合测压试验结果，建立了适用于CAARC高层建筑标准模型的顺风向、横风向及扭转向层风荷载的功率谱经验公式。研究了某L型截面高层建筑风压分布及风荷载特性。利用瞬态风压积分法推导了适用于主体结构抗风设计的整体体型系数。对负压区的测点脉动风压概率分布特性进行了分析，证明采用高斯分布对极值风压进行估算并不合理。风致响应和等效静力风荷载的分析结果表明：位移响应只需考虑第一阶模态的影响，加速度响应至少需要考虑前三阶模态的影响；顺风向的静力等效风荷载由平均风荷载控制，横风向的静力等效风荷载由惯性风荷载控制。对比研究了新、旧荷载规范的风振系数计算结果与风洞试验结果，指出新规范的风振系数比旧规范有所提高，风洞试验的风振系数结果在建筑物底部比新规范值小，随着高度的增加，逐渐增加并超过规范值。在4种典型地貌条件下，完成了8种不同几何尺寸的L型截面高层建筑刚性模型的同步测压试验，并根据试验结果对L型截面高层建筑表面风压分布特性进行研究，讨论了风向角、湍流强度、厚宽比、高宽比、测点高度等因素对平均风压和脉动风压分布的影响。总结了L型截面高层建筑在典型风向角下各立面的风荷载体型系数。对L型截面高层建筑表面测点脉动风压的功率谱特性和相干性进行了研究。利用偏度-峰度检验法，给出了L型截面建筑表面测点非高斯性区域的划分标准，并基于广义极值分布理论，对峰值因子进行了合理的估算。研究了L型截面高层建筑的三分力系数和基底力矩系数，确定了风荷载作用的最不利风向角，并对最不利风向角下的三分力系数和基底力矩系数功率密度谱进行了讨论。以厚宽比和地貌类型为基本变量，利用最小二乘法分别建立了适用于L型截面高层建筑顺风向、横风向及扭转向风荷载的数学模型，同时建立了顺-扭、横-扭风荷载的相干函数的数学模型，并采用算例对风荷载数学模型的可靠性和精确性进行了验证。基于虚功原理和瑞利商原理，建立了以梁、柱、剪力墙构件的截面尺寸为设计变量、建筑物的自重为目标函数、建筑物的风致响应为约束条件的L型截面高层建筑抗风优化设计数学模型。根据Kuhn-Tucker条件，对优化设计过程中采用的最优准则法进行了详细的推导。通过算例对该高层建筑抗风优化设计方法的有效性和经济性进行了验证，结果表明：优化设计后，，建筑物的整体刚度显著提高，总重量比优化前降低了18.1%，横风向等效静力风荷载减小约为9.03%。本文以风洞试验为主，结合理论分析详细研究了L型截面高层建筑的风荷载特性及其抗风优化设计。研究成果可为L型截面高层建筑的抗风设计、优化设计及荷载规范相关条文的修订提供参考依据。
[Abstract]:With the development of science and technology level and the increasingly tense of urban land use , high - rise buildings gradually move towards higher , lighter and more flexible trend , and the shape of high - rise buildings is more complicated . Based on the comparison between the test results of different wind tunnel research institutions , the reliability of the test equipment , flow field simulation , data acquisition and processing technology of the wind tunnel test room of the building and environment of Hunan University is verified . At the same time , the empirical formula of the power spectrum of the wind direction , the transverse direction and the torsional direction layer wind load applied to the CAARC high - rise building standard model is established by comparing the test results with the different wind tunnel research institutions . The wind pressure distribution and wind load characteristics of a high - rise building with L - shaped cross - section are studied . The integral type coefficient suitable for the design of the main body structure is derived by the transient wind pressure integral method . The results of the wind - induced response and the equivalent static wind load show that the wind - vibration coefficient of the new criterion needs to be controlled by the average wind load , and the static equivalent wind load of the wind tunnel is controlled by the inertia wind load . The wind - vibration coefficient of the wind tunnel test is smaller than the old standard , and the wind - vibration coefficient of the wind tunnel test is smaller than the new specification value , and the wind - vibration coefficient is gradually increased and exceeds the specification value with the increase of height . In this paper , the influence of wind load on average wind pressure and fluctuating wind pressure in high - rise building with L - shaped cross section is studied under the condition of four typical geomorphologic conditions . The influence of wind direction angle , turbulence intensity , thickness - width ratio , height - width ratio and height of measuring point on average wind pressure and fluctuating wind pressure distribution is discussed . The three - component force coefficient and the base moment coefficient of the L - shaped cross - section high - rise building are studied , the most unfavorable wind direction angle of the wind load is determined , and the three - component force coefficient and the foundation moment coefficient power density spectrum at the most unfavorable wind direction angle are discussed . Based on the principle of virtual work and Rayleigh quotient , a mathematical model of wind resistance optimization of high - rise building with beam , column and shear wall is established . Based on wind tunnel test , the wind load characteristics and wind resistance optimization design of high - rise buildings with L - shaped section are studied in detail by combining theoretical analysis .

【学位授予单位】：湖南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU973.213

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