【作者】 李小伟；

【导师】 赵均海；

【作者基本信息】 长安大学 ， 结构工程， 2009， 博士

【摘要】 古建筑是历史上科学文化、政治经济、艺术特征的实物载体,代表着一定历史时期的物质与精神文明。抢救国家和人类重要文物艺术的责任感和使命感,激发了广大建筑、艺术、考古、结构等领域学者研究古建筑的热情。近20年来,在结构领域,古建筑木构架的抗震机理以及力学性能研究已经引起了很多学者重视,并作了一系列有益的开拓工作,这些工作非常难能可贵。虽然如此,还有许多研究领域有待于研究：例如,古建筑历史价值较大的宫式建筑基本上都是多跨的,目前,对于多跨木结构抗震性能研究还较少；倒梯形燕尾榫卯的连接性能研究刚刚开始,近代木结构常用的上下等宽燕尾榫卯的半刚性连接力学模型还没有完全建立；用于木结构力学分析的方法还有待于改进。针对以上几个问题,根据历史文献记载,确定了宋代分心斗殿堂的结构原型,宋代分心斗殿堂是一种双跨古建筑木结构,常常用于建筑群的正门。这种结构是多跨木结构的一种,它的构造相对简单,通过这种结构力学特征和工作性能的研究,可以为多跨木结构的后继研究工作奠定基础。以宋代分心斗八架椽殿堂木构架为原型,制作了3榀1：4木构架缩尺模型,模型的榫卯,按照马炳坚先生的《中国古建筑木作营造技术》中记载的上面大、下面小、外面窄、里面宽的倒梯形燕尾榫卯制作方法制作。根据古建筑木构架与柱础、柱顶的连接条件,对试件的边界条件和加载方式进行了合理假定,对所制作的3榀木构架试件进行了拟静力实验。分析了双跨木构架的滞回曲线、骨架曲线,骨架曲线的强度、刚度退化特征,分析了双跨木构架的耗能能力,确定了双跨木构架的骨架曲线模型,根据多线型枢纽点Pivot模型,提出了适合于木结构的修正双线型枢纽点滞回模型和修正多线型枢纽点滞回模型。木结构的节点连接是弱节点榫卯连接,对于木结构,实验时作动器力的示值与P-△效应产生的二阶水平力处于一个量级,当位移较大时,忽略P-△效应,将会使分析结果误差较大。提出了基于等效框架的虚拟荷载法和基于等效框架的D值法,这些分析方法主要适用于分析半刚性连接框架,可以考虑结构非线性和整体二阶效应,用这些分析方法所得的结果与实验结果吻合较好。对木构架半刚性节点的弯矩一转角关系进行了深入研究,确定了节点连接弯矩与节点连接刚度、柔度的计算公式；节点连接相对转角与位移关系的计算公式,位移与节点连接刚度、柔度的计算公式。确定了节点弯矩—连接相对转角的双线型模型和幂函数模型。通过计算机模拟验证了节点连接弯矩—连接转角幂函数模型用于计算机分析的适用性。测试了双跨木构架的模态参数,根据幅频峰值法和实频、虚频峰值法,计算了双跨木构架的一阶模态频率和一阶模态阻尼比,对计算结果进行了深入分析。更多还原

【Abstract】 Ancient building represented science, culture, politic, economic and art in historic period, and could reflected material and cultural progress. The senses of responsibility and mission of protecting and rescuing those human relics arouse the enthusiasm for historic building of researchers in architecture, art, archaeology and structure areas. In past 20 years, quite a few scholars were coming to study the seismic mechanism and mechanical performance hidden in Chinese ancient timber structure, and doing some excellent pioneering workings. Still, many problems were remained to be studied. Traditional multi-span timber structures remain largely unexplored until current days. It is recorded in the book of Construction Technique in Chinese Traditional Timber Structure written by Ma BingJian that the cross-section of traditional dovetail looks like an upside down trapezoid (wide on the top side, and narrow at the bottom side). This inverted trapezoid dovetail is expected to be studied. Besides, the mechanical model of semi-rigid connector for ordinary tenon with rectangular cross-section is still not built up. The analysis approaches used to wooden structures are not yet excellent.Fen-Xin-Dou palace built in Song Dynasty is double span wooden structure, and used for the main entrance of ancient buildings. Double-span timber structure is a special sort of multi-span timber structures, and its details are simpler than other multi-span structures. Research on the structure can lay the groundwork for subsequent studies of multi-span wooden structures.Based on Fen-Xin-Dou palace built in Song Dynasty, three scaled model with the ratio of 1:4 are built, and its connector is made as inverted trapezoid dovetail. According to the realistic connection condition at the bottom and top of column, the text makes rational assumptions about the boundary conditions and loaded modes for the test samples, and reports the results of pseudo-static tests of the three samples.The samples made of either steel or concrete, rather than timber, have larger capacities resisting lateral force and lower ductility. For these samples, the overall P-A effects induced by structural displacement are only the test values of actuator of 1/20～1/10 in test process, thus, we can neglect the overall P-△effects in analyzing test values, and the errors resulted by the simplification will be small. But the second order lateral force induced by overall P-△ effects of timber structure, with semi-rigid joggle joint, is 0.3～3.5 times of the test values of actuator. When lateral displacement of structure is relatively larger, the lateral force by P-△effects occupies the leading position, so, P-△effects should be concern in dealing with the test results of wooden samples.Both virtual load and D-value method based on equivalent portal frame are presented. Those methods take the non-linear effect and overall P-△effects into consideration, and are validated with a broader range of test results. They can be more incorporated into frame analysis with semi-rigid joints for predicting system response.Formulas are obtained, such as relationships between connectional moment and stiffness, between connectional moment and flexibility, between lateral displacement and relative angle of wedge joint, between lateral displacement and connectional stiffness in joints, and between lateral displacement and connectional flexibility in joints. Besides, both double-line and power functional model between connectional moment and relative angle in joints are decided. Based on multi-linear pivot hysteresis model, both revised bi-linear and multi-linear pivot hysteresis model are presented. The power function representation between connectional moment and relative angle in joints is validated with the results of a number of computer imitations, and is suited to estimate the responses of semi-rigid timber frame.Mode parameters of 3 double span wooden structures were tested. Besides, based on both methods of the amplitude-frequency peak value and of the real-frequency and imaginary-frequency peak value, fundamental frequencies and fundamental mode damping ratios of tested samples were estimated.更多还原