中国古建筑木结构加固及其性能研究

发布时间：2018-04-05 04:29

本文选题：古建筑木结构　切入点：碳纤维布　出处：《西安建筑科技大学》2013年博士论文

【摘要】：古建筑木结构由于其独特的结构特性而具有优良的力学性能，使得像山西佛光寺大殿以及五台山南禅寺大殿这些经历千年风吹雨打和多次地震的典型古建筑物依然屹立于中华大地。然而，在漫长的历史岁月中，由于材料的老化、腐朽、虫蛀以及强震、战火、风雨侵蚀等自然力以及人为的破坏，再加上多年来对其保护不够重视、年久失修，使得这些现存古建筑木结构处于结构体系破坏、多种病害缠身、险情不断发展甚至潜伏坍塌的危险状态。因此，作为国家重点文化保护遗产的现存古建筑木结构建筑物，其修缮加固工作变得尤为重要。本文结合汶川地震后对现存古建筑木结构的震害调查，通过系统归纳和分类统计，对古建筑木结构的地基基础、梁柱和g揾1等构件、榫卯节点、整体稳定性以及围护结构在地震作用下的破坏情况及破坏原因、木材性能退化等进行了详细的分析和探讨；并针对结构不同的破坏情况，提出了相应的抗震加固方法。为了掌握古建筑木结构地震作用下的破坏过程及对应的破坏状态，对震后古建筑木结构的破坏程度做出合理的评估，基于燕尾榫柱架和g揾1铺作层低周反复荷载作用下的滞回特性和能量耗散原理，将燕尾榫柱架和g揾1铺作层看做两耗能构件，计算出其在低周反复荷载作用下的“抵抗破坏潜能”；根据古建筑木结构振动台试验，计算出各工况地震作用下每一耗能构件所耗散的能量；基于构件的“抵抗破坏潜能”和各工况下的地震耗能情况建立耗能构件在不同地震作用下的地震破坏评估模型，并借助于能量分配系数找出了各耗能构件破坏状态与整体结构破坏状态之间的关系，从而建立整体结构在不同地震作用下的破坏评估模型。应用该地震破坏评估模型，分别对燕尾榫柱架和g揾1铺作层以及整体结构进行构件地震破坏评估和整体结构地震破坏评估，所得到的破坏系数能较好地反映各构件以及整体结构在不同地震作用下的破坏状态。对按照宋代《营造法式》构造要求制作的古建筑木结构实体加固模型进行模拟振动台试验。选用三条地震波分别对结构模型的柱根、柱头、铺作、乳h?的位移、加速度响应、地震剪力以及榫卯节点的内力进行定量研究，并对结构的破坏形态、动力特性、扭转效应进行定性分析。研究结果表明：柱础的摩擦滑移、半刚性榫卯节点的转动以及g揾1铺作层的滑移使得结构模型地震响应大幅度减小，满足“小震不坏、中震可修、大震不倒”的设计要求；结构模型最大剪力沿高度的分布出现在柱架层或柱础层，并非一定出现在结构的柱础最低层；得出榫卯节点不同工况下的转动弯矩最大值；由于高振型的参与以及质量和刚度不均匀分布，结构模型在400Gal后出现明显的扭转。根据碳纤维布加固古建筑木结构力学性能，基于试验和理论分析，分别得出了能够体现碳纤维布加固古建筑木结构独特受力性能的各关键部位或构件的恢复力特性曲线；用Combine40弹簧单元、Combine39弹簧单元+Combine14弹簧单元以及Combine39弹簧单元简化模拟柱脚与础石间的摩擦滑移特性、半刚性榫卯及g揾1连接，建立整体结构的有限元计算模型。模态分析得出了结构模型的前十阶振型及自振频率。地震响应分析显示，随着地震动强度的增大，结构各层的最大位移值和加速度值逐渐增大，同时各层的动力放大系数越来越小，说明大震时半刚性榫卯连接的减震效果比中震和小震时的减震效果要好。殿堂式古建筑木结构由于其独特的构造特点而具有与现代建筑结构不同的抗震性能，现有的结构动力分析模型对于古建筑木结构不再适用。基于其水平地震作用下的受力性能及动力破坏形态，给出了关键构件的简化分析模型，将柱架简化为“摇摆柱”，将g揾1铺作层简化为“剪弯杆”；根据简化分析模型及整体结构质量分布情况，提出了单层殿堂式古建筑木结构的两质点“摇摆-剪弯”动力分析模型；结合构件试验以及动力学理论推导得到了动力分析模型不同受力状态下各参数的计算方法及适用范围，并与振动台试验结果进行对比。结果表明，提出的动力分析模型可以较好地反映单层殿堂式古建筑木结构在水平地震作用下的动力反应。最后，结合碳纤维布和扁钢加固燕尾榫节点在外荷载作用下的受力破坏性能，并根据试验破坏情况，，提出了碳纤维布和扁钢加固古建筑木结构燕尾榫节点的抗弯承载力计算公式，并给出了合理的加固设计建议，为古建筑木结构的修缮加固提供理论依据。
[Abstract]:Ancient timber structure has excellent mechanical properties due to its unique structural characteristics, such as the Shanxi Great Hall of Foguang temple and Mount Wutai nanchansi temple through the millennium and the typical earthquakes exposed to wind and rain of ancient buildings still standing in China. However, in the long years of history, due to material aging, decay, and moth earthquake, fire, wind and rain erosion and other natural and man-made destruction, plus years of its protection is not enough attention to the state of disrepair, the existing ancient wooden structures in the structure damage, disease ridden, development and even the danger lurking danger state collapse. Therefore, as the extant ancient wooden structures in the national key cultural heritage buildings, the repair work has become particularly important.
According to the Wenchuan earthquake disaster investigation of existing ancient timber structure, through the systematic induction and classification statistics, the foundation of ancient architecture, and made 1 g beam column element, mortise tenon joints, the overall stability and retaining structure damage under earthquake and the causes of damage and degradation properties of wood carried out a detailed analysis and discussion; and for the destruction of different structure, put forward the corresponding seismic reinforcement method.
In order to grasp the failure process and failure state corresponding to seismic wooden structure of ancient buildings under the effect, make a reasonable assessment of the earthquake damage of ancient timber structure, dovetail column frame and G can shop for 1 layer under low cyclic loading hysteretic behavior and energy dissipation principle based on the dovetail column frame and G can shop for 1 layer as two energy component, calculated under low cyclic loading "resistance failure potential"; according to the ancient timber structure shaking table test, calculate the earthquake under the action of each energy component by the dissipation of energy; the establishment of energy component seismic energy dissipation member resistance the potential damage and under different working conditions based on different earthquake damage assessment model, and based on the energy distribution coefficient was found between damage state and the overall structure of the energy component damage state, from The damage assessment model and establish the overall structure in different earthquake. The seismic damage assessment model, respectively. The dovetail column frame and G can shop for 1 layer and the overall structure of the component seismic damage assessment and the overall structure of seismic damage assessment, failure damage coefficient obtained can reflect each component and the overall the structure under different earthquake action.
The French construction entity > ancient wooden structures produced by the shaking table test model according to the Song Dynasty. "Create a reinforcement of three seismic waves were selected column roots, the structural model of stigma, shop, milk H? Displacement, acceleration response, quantitative research of seismic shear and internal force of mortise and tenon joints, and the failure modes, the dynamic characteristics of the structure, the torsional effect is qualitatively analyzed. The results show that: the friction base, rotating semi-rigid mortise tenon joint and G can shop for 1 layer slip structure model which the seismic response is greatly reduced, to meet the" minor earthquake, repairable under moderate earthquake, design requirements the earthquake does not fall "; the structure model of the maximum shear in the column frame layer or the base layer along the height distribution, not necessarily appear in the lowest layer zhuchu structure; the tenon joints under different conditions the maximum moment due to high rotation; The participation of the vibration mode and the uneven distribution of the mass and stiffness, the structural model appears obviously torsional after 400Gal.
According to the mechanical properties of wooden structure of ancient buildings strengthened with CFRP, based on experimental and theoretical analysis, were obtained to reflect the CFRP ancient wooden structures by unique key positions of the force performance and restoring force characteristic curve; Combine40 spring unit, Combine39 unit and Combine39 unit +Combine14 spring spring spring element simplified simulation the friction characteristics of the column and base between semi-rigid, tenon and G make 1 connections, the overall structure of the finite element calculation model. The modal analysis obtained the structure model with ten modes and natural frequency. The seismic response analysis showed that with the increase of seismic intensity, and acceleration values gradually increase the maximum the displacement of each layer, and each layer of the dynamic amplification coefficient is more and more small, illustrate the shock absorption effect damping effect of semi-rigid mortise and tenon connection than moderate and small earthquakes when the earthquake occurs It's a good fruit.
Palace style of ancient wooden structure seismic behavior is different from modern building structures due to its unique structural characteristics, the model is no longer suitable for ancient wooden building. The existing structure dynamic analysis under horizontal earthquake force performance and dynamic failure mode based on the analysis for the simplified model of the key components of the column frame is simplified as a "swing column", will make the G shop for 1 layer simplified to "shear bending rod"; according to the simplified mass distribution model and the overall structure of the situation, put forward the monolayer hall style ancient timber structure of the two particle "swing and shear bending dynamic analysis model; combining component test and dynamic theoretical derivation the calculation methods of the parameters of dynamic analysis model under different stress state and scope, and compared with the results of shaking table test. The results show that the proposed dynamic analysis model can be used to It reflects the dynamic response of the single storey palaeo architectural wood structure under the horizontal earthquake.
Finally, combined with carbon fiber cloth and steel reinforcement dovetail joints in the external load damage performance, and according to the failure test, the bearing capacity calculation formula of flexural strengthening of ancient timber structure dovetail with CFRP and steel joints is put forward, and gives reasonable suggestions of strengthening design, provide a theoretical basis for the as the ancient wooden building repairs and reinforcement.

【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU366.2

【参考文献】