钢—木螺栓连接木结构框架火灾反应试验研究

发布时间：2018-04-04 16:18

本文选题：钢-木螺栓连接　切入点：木结构框架　出处：《东南大学》2016年硕士论文

【摘要】：木结构建筑在我国的发展拥有悠久的历史,近年来,随着我国经济的迅猛增长,建筑结构形式的发展日趋多元化,绿色环保、舒适健康的建筑需求使得木结构建筑再次成为建筑领域的热点。在我国的既有建筑中,存在大量具有历史价值和文化价值的古木建筑,与此同时,木结构也因纹理美观、材料环保可再生而被广泛运用于新建建筑中。据统计资料显示,近年来我国建筑火灾的发生呈增多的态势,火灾具有极大的危害性,造成大量的财产损失和人员伤亡。我国现存的诸多木结构建筑都不可避免地面临着火灾的威胁,然而,木结构抗火在我国的研究尚处于初级阶段,虽然已有部分学者开展了相关的试验与理论研究,但远不能满足木结构发展和应用的需求。在防火设计方面,我国现行规范中有关木结构防火的相关规定主要参考欧美发达国家规范制定,缺乏基于我国研究人员科研成果的运用。鉴于上述情况,加强木结构建筑抗火性能的研究具有重大的意义。本文以钢-木螺栓连接木结构框架为研究对象,开展了火灾试验研究和有限元软件ABAQUS平台上的火灾环境下模型热-力耦合分析,主要内容可分为以下几个部分：(1)从木材的炭化机理、炭化速度和木结构火灾下的力学性能等角度,总结和回顾国内外学者在木结构抗火性能研究领域的主要工作与成果。(2)以有限元软件ABAQUS为平台,采用温度场-结构场顺序耦合分析方法对既有试验进行模拟,通过试验结果与计算结果的对比验证了该分析方法的有效性。(3)以现代木结构常用的钢填板螺栓连接T型节点为考察对象进行参数分析,通过有限元软件ABAQUS计算分析了火灾条件下,持荷水平、螺栓直径和螺栓边距对节点的破坏模式与耐火极限的影响。结果表明,持荷水平的增大、螺栓直径的增大以及螺栓边距的减小均会导致耐火极限的降低。(4)以钢-木螺栓连接木结构框架为试验对象,进行了1榀常温下静载试验和3榀高温下耐火极限试验,考察了持荷水平、隅撑设置对木结构框架破坏模式与耐火极限的影响。结果表明,降低试件持荷水平和增加隅撑均为提高试件耐火极限的有效途径；增设隅撑改变了原木框架的内力分布,减小了跨中弯矩和梁端剪力,从而延缓了梁端剪切破坏的发生。(5)以钢-木螺栓连接木结构框架为考察对象进行有限元模拟,分析了整体框架在火灾条件下的结构响应和内力变化情况。(6)结合国内外木结构设计规范,针对木结构的抗火设计提出建议,采用“折减截面法”对《木结构设计手册》中常温下的承载力计算公式进行适当转化,获得了火灾条件下梁、柱构件与螺栓连接的承载力计算公式。
[Abstract]:Wood structure architecture has a long history in our country. In recent years, with the rapid growth of our economy, the development of building structure forms is becoming more and more diversified, green environmental protection.The comfortable and healthy building demand makes the wooden structure architecture become the hot spot in the field of architecture again.Among the existing buildings in China, there are a large number of ancient wooden buildings with historical and cultural values. At the same time, wood structures are widely used in newly built buildings because of their beautiful texture and environmentally renewable materials.According to statistical data, the occurrence of building fires in our country is increasing in recent years, fire has great harm, resulting in a large number of property losses and casualties.Many existing wood structure buildings in China are inevitably facing the threat of fire. However, the study of wood structure fire resistance in China is still in the primary stage, although some scholars have carried out relevant experiments and theoretical studies.But far from meeting the demand of wood structure development and application.In the aspect of fire prevention design, the relevant regulations on fire prevention of wood structure in the current code of our country mainly refer to the norms of developed countries in Europe and the United States, and lack the application based on the scientific research results of Chinese researchers.In view of the above situation, it is of great significance to study the fire resistance of wood structure buildings.In this paper, the steel-wood bolted timber structure frame is taken as the research object, the fire test research and the thermal-mechanical coupling analysis of the model under the fire environment on the finite element software ABAQUS platform are carried out.The main contents can be divided into the following parts: 1) from the perspective of the carbonization mechanism of wood, the carbonization speed and the mechanical properties of wood structures under fire,This paper summarizes and reviews the main works and achievements of domestic and foreign scholars in the field of wood structure fire resistance. Based on the finite element software ABAQUS, the existing tests are simulated by the sequential coupling analysis method of temperature field and structure field.The validity of the analysis method is verified by comparing the test results with the calculated results. The parameter analysis is carried out with the steel stud bolted T-joints commonly used in modern wooden structures as the object of investigation.The effects of load holding level, bolt diameter and bolt edge distance on the failure mode and fire resistance of joints under fire conditions were analyzed by finite element software ABAQUS.The results show that the increase of load holding level, the increase of bolt diameter and the decrease of bolt edge distance will lead to the decrease of fire resistance limit.A static load test at room temperature and three fire limit tests at high temperature were carried out. The effects of load holding level and corner bracing on the failure mode and fire resistance limit of wood frame were investigated.The results show that reducing the load holding level and increasing the corner brace are the effective ways to increase the fire resistance limit of the specimen, and the addition of corner brace changes the internal force distribution of the log frame and reduces the bending moment in the span and the shear force at the end of the beam.Thus delaying the occurrence of shear failure at the end of the beam. (5) taking the steel-wood bolted timber structure frame as the object of investigation, the finite element simulation is carried out.The structural response and internal force variation of the whole frame under fire condition are analyzed. (6) combined with the design code of wood structure at home and abroad, some suggestions for the fire resistant design of wood structure are put forward.The formula for calculating the bearing capacity of beams, columns and bolts under fire condition is obtained by properly transforming the formula of bearing capacity under normal temperature in the Design Manual of Wood structures by using the method of "reduced Section method", and the formula for calculating the bearing capacity of beams, columns and bolts under fire conditions is obtained.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU398.6;TU352.5

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