基于FBG应变测量的古建筑木梁变形监测方法  

A deformation monitoring method of ancient wooden beam based on FBG strain measurement

作　　者：姜绍飞[1] 唐伟杰[1] 吴铭昊 沈圣[1] 张鹰[2] 

机构地区：[1]福州大学土木工程学院,福建福州350116 [2]福州大学建筑学院,福建福州350116

出　　处：《地震工程与工程振动》2016年第6期198-206,共9页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51278127;51278123;51678156)~~

摘　　要：针对传统测量方法在古建木梁实际变形监测中存在的不足,本文基于光纤布拉格光栅(FBG)应变测量技术结合构造函数法提出一种古建筑木梁挠度变形监测的新方法。该方法考虑了木梁两端榫卯连接半刚性支座、支座沉降和原木梁截面不规则三个因素,推导了应变测量结合构造函数法的古建木梁挠度计算公式;建立有限元仿真模型,得到所提方法在木梁监测中的最优传感器布设数量,并探讨了在实际工程中的适用范围;通过对木构架梁进行了静力加载试验来验证该方法的有效性,并分析支座沉降与截面不规则对挠度变形的影响程度。研究结果表明,本文所提的方法适用于半刚性支座的木梁,能够消除支座沉降与截面不规则的影响;该方法适合用于跨高比大于20的在役古建筑木梁挠度监测,仅需在5个位置布设FBG应变传感器即可满足精度的要求;支座沉降相对于截面不规则而言,其对挠度变形影响较大,且影响程度与加载模式无关。In order to overcome the drawbacks of traditional measurement methods in the monitoring of ancient wooden beams, the paper proposes a new deformation monitoring method for ancient wooden beams based on fiber Bragg grating （FBG） strain measurement technique and the constructor method. More specifically, this proposed method takes three factors into account, i. e. , semi-rigid support located in mortise and tenon connection, support settlement and the irregular cross section of original wooden beams, and a formula is derived and presented for ana- lyzing the deflection of ancient wooden beams. A finite element model （FEM） is built to analyze the scope of appli- cation of the proposed method in engineering; meanwhile, the proper number of sensors is recommended. Besides, the proposed method is validated by static loading test conducted on beams of a wooden frame, and the influence degree of support settlement and irregular cross section on the deformation is analyzed. The results show that the method is applicable to the ancient wooden beams of semi-rigid support, and the effect of support settlement and the irregularity of cross section can be eliminated. Moreover, the method can be applied to the deformation monitoring of ancient wooden beams whose span-depth ratios are larger than 20, and the accuracy can be met by arranging only5 FBG strain sensors in the proper places. The influence on the deformation of settlement is larger than that of irreg- ular cross section, which is irrelevant to loading modes.

关 键 词：古建木梁 构造函数法 变形监测 跨高比 FBG应变传感器 

分 类 号：TU366.2[建筑科学—结构工程]