【作者】 王林安；

【导师】 沈世钊； 樊承谋；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2006， 博士

【摘要】 古建筑木结构的体型一般很大,构件因横纹局压而产生过大的变形甚至严重破坏的现象非常普遍,这是其修缮加固中的关键问题,而且在应县木塔中尤为突出。应县木塔是参考唐代2~3层殿堂结构的建造经验,将殿堂依次叠合而成的高耸木结构,明、暗共9层,高67.31米。相对于一般殿堂结构,高度和自重的成倍增加,使木塔遇到前所未有的两项难题:其一是因自重增加,使承受上层柱轴向荷载的梁(普拍枋和梁栿）横纹局压应力成倍地超过设计强度而产生严重的压缩变形甚至劈裂,导致木塔整体竖向变位。其二是因高度增加,地震荷载作用下的安全可靠成为木塔整体结构的主要问题。由于木塔采用了唐代殿堂内、外分槽的结构形式,用两层柱圈构成筒体,并逐层加设了层高较低称为平坐的刚度加强层,再加上两圈柱子都由下至上向内倾斜对筒体形成环箍力,这些措施帮助木塔抵抗了多次强烈地震而未倒。但是,目前木塔残留的整体倾斜、层间侧移以及由木材横纹压缩引起的竖向压缩变形等都已达到严重影响其安全可靠的程度,所以,木材横纹局压增强加固问题亟待解决,以防突变。本文首先研究了木塔结构构造和残损情况,并结合木材的微观构造,探讨了横纹承压的传力机理和横纹承压强度设计值的确定方法。然后计算了木构件横纹局压的抗力作用效应比。分析发现,木塔底部几层普拍枋和梁栿(柱脚下的横梁)的横纹局压抗力作用效应比最小的仅有0.24,势必产生过大的变形,是引起木塔高度降低的主要原因,也是木塔当前最大的安全隐患。针对木材横纹局压的受力特点和加固目标,本文提出“插筋法”增强古建筑木构件的横纹局压承载力的技术,研究增强机理和加固后的力学性能,探讨制作工艺及在应县木塔中的应用问题。普拍枋的截面高度相对较小,横纹局压高应力区贯穿整个构件截面,采取棒材两端直接承压的技术;梁栿的截面高度较大,增强棒材一端承压,另一端没有直接承压面,靠棒材与木材之间的胶层摩擦传递荷载。普拍枋中增强棒材的受力形式相当于木材侧向弹性约束下的轴压问题,因而,先从理论角度分析了侧向弹性约束下棒材的计算长度系数的计算方法,进而求得其长细比和稳定承载力。然后设计了一系列试验验证了理论分析的正确性。同时还研究了木材边距、间距和端距对棒材稳定承载力的影响,计算求得木材边、端距的最小值。最后,通过钢筋增强木材横纹局压标更多还原

【Abstract】 Yingxian ancient wooden pagoda is a flat-form tall building, which was formed by the superposition of monolayer temples. The height of 67.31 meters made it encountered two unprecedented puzzles : Firstly, with the height increased whopping, wind resisting and aseismatic capability become the main question of the whole structure; secondly, because of the weight increased unconventionally, members of the lower 1~3 floors hold overloading perpendicular to grain and they brought large vertical deformation. It lead that the whole structure’s compress deformation developed sequentially.Yingxian Wooden pagoda has favorable aseismatic capability, as it used similar modern core-in-core structure, and fixed many batter brace make it become modern rigid reinforced floors in every hidden floor , and slope of bearing post made it that the level and uprightness frame integrate tightly. Under the deadweight, every structural floors form centripetal force. Those earthquake resistant measures resist many the strong destroy of earthquake in history.First of all, the structural characteristic and essential of damages were introduced. Secondly the efficiency factor of how much the compression stress perpendicular to grain is more than the design value was calculated. Thirdly, the main reason that members were made too large deformation and serious damage was pointed out. The key technologies that control wooden pagoda vertical compressive deformation were conducted. For the members that have high damnification and were lacking of bearing capacity need be replaced. Northeast larch that has high strength and corrosion resistance is the prime timber, but this timber is easy to crack, so their crack resistance need studied. Simplified result of Earthquake effects indicate that earthquake resistant capacity are obviously scarce and need to be reinforced.Secondly, Combining with the timber one-dimensional structural characters, the dissertation bring forward the technology that GFRP stick and steel bar reinforce the timber members whose compression perpendicular to grain have excess load and discuss the craftwork how to do the reinforced members. The更多还原