【作者】 刘小根；

【导师】 包亦望；

【作者基本信息】 中国建筑材料科学研究总院 ， 材料学， 2010， 博士

【摘要】 玻璃幕墙越来越广泛应用于高层建筑,是现代建筑重要组成部分。然而,伴随着玻璃幕墙使用量的增多及服役年限的增加,玻璃幕墙的质量问题越来越突出,幕墙玻璃突发破裂或坠落事故时有发生,严重威胁着人们的生命财产安全。因此,如何现场检测及监测既有玻璃幕墙服役健康状态,确立一套评估玻璃幕墙可靠性标准受到材料界和工程界科研人员的普遍重视,也是保障玻璃幕墙在使用中预防灾害发生,减少经济损失所迫切需要解决的核心问题。玻璃幕墙的结构失效,材料失效将影响其安全性能,而功能失效又会加速其结构与材料失效。基于此,本文重点研究了玻璃幕墙支承体系结构与材料失效及幕墙玻璃面板功能失效的在线检测理论与安全评估新技术,具体完成了如下研究工作内容:(1)提出了通过振动测试方法获得幕墙玻璃的固有频率来识别玻璃幕墙支承结构松动损伤及其结构胶的老化程度。试验室研究了四边夹支及隐框玻璃幕墙在其支承结构体系出现松动、老化和损伤后幕墙玻璃的固有频率变化规律。试验结果表明了四边夹支幕墙玻璃板的固有频率随其边界支承松动而不断衰降,且分布在低于玻璃边界四边固支和高于四边简支对应的频率约20%的区间内;随着结构胶老化时间增长,因结构胶对玻璃粘结强度不断降低,表现为幕墙玻璃板的固有频率变化率也不断增大。根据试验结果,结合矩形薄板边界约束与其动态参数关系,本文建立起了一套以幕墙玻璃板固有频率变化来评价玻璃幕墙支承结构松动损伤及玻璃脱落风险的标准,由于幕墙玻璃板固有频率是一个比较容易获得的动态特性参数,因此,该方法是一种现场检测既有玻璃幕墙安全性能的简便方法。(2)针对幕墙中空玻璃密封性能失效及外片脱落等质量事故问题,首先直接根据中空玻璃内外片玻璃两面承受的气体压差导致的变形求出中空层体积变化,并结合中空层气体理想状态方程,精确地计算了外载及环境因素影响下中空玻璃内外片变形及应力分布大小,解决了环境温、压差给中空玻璃带来的附加应力和变形理论定量计算这一问题,也为幕墙中空玻璃承载能力验算、工程安全应用及密封层失效在线检测技术提供理论指导。根据中空玻璃中空层气体泄漏前后中空玻璃承载变形性能的变化,提出了采用在中空玻璃面板中心施加集中荷载,通过观测中空玻璃内外片变形量的大小来评价中空玻璃中空层的密封性能,实现了在线检测幕墙中空玻璃中空层密封性能。(3)为满足建筑幕墙用安全型真空玻璃的开发及工程应用推广之需要,研究了安全型真空玻璃结构优化设计及应用所必须涉及的力学基础理论。根据真空玻璃结构特点,建立了力学模型,分析了真空玻璃在大气压作用下支撑应力分布特征及计算公式。针对真空玻璃在工程应用中的强度设计关键问题,研究了均布载荷下真空玻璃弯曲失效特性及影响因素,给出了幕墙用真空玻璃强度计算公式。通过上述研究,为安全型真空玻璃结构与强度设计及其工程应用提供了理论基础。另外,提出了基于光弹法和动态法在线检测真空玻璃的真空度,建立起了应力光弹斑痕变化及真空玻璃固有频率与真空玻璃真空度之间的关系,为幕墙真空玻璃真空度失效提供了简便在线检测方法。更多还原

【Abstract】 Glass curtain wall is widely used in high building, and becomes one of the most important parts of modern structures. With the increase of total amounts and service life, spontaneous breakage or falling down of curtain wall glass in service have been frequently reported, and resulted in a lot chaos, causing economic loss or even serious disaster. Therefore, the methods of damages detection, risk prediction and safety evaluation of a curtain-wall system, have attracted great attention of materials scientist and structure engineer. Furthermore, it is also urgent to ensure the safety of glass curtain wall and to prevent calamitous accident.Failure of structure and materials may influence the safety performance of the curtain wall glass seriously, and the failure in the function of the curtain wall glass may accelerate structure and materials failure. In this work, therefore, the focuses are put on the on-site detection technique of structure failure under different support systems, and function failure of the glass in the glass curtain wall. The primary research works and obtained results are as follows:(1) A vibration method is proposed to predict the loosening extent of the support structure and aging extent of the structure sealant based the natural frequency changes of the curtain wall glass. A relationship between the frequency changes and the reliability of the glass curtain wall with various supports were established by experiment. The results indicate that there exist an upper limit and lower limit for the measured natural frequencies of a glass fixed at four sides. The upper lower limit is about 20% higher than the frequency of the simply supported plate with the same size, and the upper limit is nearly 20% below that of the clamped supported plate. Aging tests of the structure sealant in concealed frame glass curtain wall exhibit an interesting phenomenon that the natural frequencies of the glass declined with the increasing aging time. Based on the obtained results, an evaluation criterion was developed to evaluate the reliability of the glass curtain wall via the changes of the measured frequency. Since frequency measurements can be cheaply acquired, the approach could provide an inexpensive assessment technique for glass curtain wall.(2) The quality problems of insulating layer failure and outer panel fall down of the insulating glazing have attracted great attention from us. In this thesis, based on the ideal gas equation and the quantity of volume changes in the insulating gas layer, the deformation and stresses distribute in the insulating glazing due to wind load, ambient temperature and pressure difference were calculated quantitatively. Thus, the quantitative calculation of deformation and stresses in the insulating glazing due to ambient temperature and pressure difference were realized. It also provides an approach for safety application, failure detection and checking the bearing capacity of the insulating glazing. Because the stiffness of the insulating glazing is changed after the failure of insulating layer, accordingly, a detection method is proposed by measuring the deflection of the inner and outer glass panels or the distance between both panels under given a concentration load at the central of the glass pane to identify the sealing performance of insulating glass.(3) In order to meet the needs of development and application of the vacuum glazing, strength theories and optimization design of the vacuum glazing were studied. Based on the structural characteristics of the vacuum glazing, the mechanical models were established and the stresses distribution in the vacuum glazing caused by atmospheric pressure was calculated. The strength behavior of the vacuum glazing and influencing factors were investigated by using uniform load test on the glass plate. The calculation formula of the resistance to wind load and strength design factors of the glass were given. Furthermore, the photo-elastic method and dynamic method were put forward to detect the vacuum degree of the vacuum glazing. It was discovered the photoelasticity figure and natural frequency of the plate depend on the vacuum degree of the vacuum glazing.更多还原