可靠度论文：基于可靠度要求的木材强度设计值确定

1、. 可靠度论文：基于可靠度要求的木材强度设计值确定【中文摘要】木材强度设计值的准确性及连接的可靠性直接影响木结构的安全,因而需要科学合理地确定进口规格材和层板胶合木的强度设计指标及正确地评估连接的可靠性。我国木结构设计规范GB50005-2003基于美国已有规格材的强度设计指标,按相同荷载作用下美国与我国木结构设计获得相同截面尺寸的原则,即软转换方法,给出了进口北美规格材的强度设计指标。正在制定的胶合木结构技术规范实际上也按软转换方法给出了我国目测分等与机械弹性模量分等层板胶合木的强度设计指标。本文对目前采用的软转换方法的可行性进行了评估,发现其不足之处是认为美国木结构设计规范与我国规范具有相

2、同的可靠度要求。本文以进口加拿大规格材为例,分别采用JC法与MC法验算了我国木结构设计规范规定的进口北美规格材强度设计值的可靠性;采用同样的方法对目测分等与机械弹性模量分等层板胶合木的强度设计值进行了验算。结果表明,我国木结构设计规范及胶合木结构技术规范给出的强度设计值偏高,不能满足我国建筑结构可靠度设计统一标准GB50068-2001的要求。因此有必要重新确定这类木结构用材的强度设计值。本文给出了相应的确定方法,以供修编相关规范参考。我国对于木结构节点连接可靠性的研究还处于初期阶段,本文给出了螺栓连接S、m及类屈服模式的功能函数,然后对其可靠性进行了评估,为木结构节点连接可靠性的研究提供了参

3、考。【英文摘要】The accuracy of design values for wood and the reliability of connections affect the safety and reliability of timber structures. It is, therefore, necessary to specify the strength design values of imported dimension lumber and glued laminated timber and to to evaluate the reliability of co

4、nnections in a scientific and reasonable way. Based on the existing strength design values of American dimension lumber,the Code for Design of Timber Structures (GB50005-2003) specified the strength design values by using soft conversion method,which means to obtain the same cross-section size of wo

5、od member by GB50005-2003 and American National Design Specification under the same design loads. Technical code of glued laminated timber structures which is being developed uses the similar method as dimension lumber to determine the strength design values of glued laminated timber made of visuall

6、y stress-graded laminations and mechanically modulus-graded laminations. In this study, the feasibility of the soft conversion method is assessed. The results showed that the shortcoming of the current conversion method is that the U.S. standards and the Chinese code have the same reliability requir

7、ements for timber structures.In this paper, the imported Canadian dimension lumber is taken for examples, and the JC and MC method are used to evaluate the reliability of imported North American dimension lumber based on the strength design values given in the Code for Design of Timber Structures. T

8、he same methods are also used to evaluate the reliability of Glulam made of visually stress-graded laminations and mechanically modulus-graded laminations, based on the strength design values given in the Technical Code Glued Laminated Timber Structures.It is found out that the strength design value

9、s given in both codes are so large that do not satisfy the requirment of The Unified Code for Reliability Designof Building Structures GB50068-2001. It is useful to re-establish the strength design values of dimension lumber and Glulam based on the target reliability index specified in China, thus t

10、o provide reference for compiling and revising of the related codes.Study of the reliability of connections in timber structures in China is still in an early stage. In this study, the performance function of bolted connections with failure modes ofs、m andare presented, and the reliability of the co

11、nnections is evaluated . This can provide reference for future study.【关键词】可靠度 规格材 层板胶合木 木结构连接【英文关键词】reliability dimension lumber glued laminated timber (Glulam) wood connection【目录】基于可靠度要求的木材强度设计值确定 摘要 4-5 Abstract 5 第1章 绪论 8-24 1.1 引言 8-9 1.2 木结构用材及连接 9-18 1.2.1 规格材 9-12 1.2.2 层板胶合木 12-15 1.2.3 木结构的

12、连接 15-18 1.3 课题背景 18-19 1.4 国内外相关课题研究现状 19-23 1.4.1 工程结构设计方法 19-20 1.4.2 可靠度的计算方法 20-21 1.4.3 木结构的可靠性 21-23 1.5 本文的主要工作 23-24 第2章 可靠度理论及在木结构中的应用 24-38 2.1 引言 24 2.2 可靠度的基本原理 24-26 2.2.1 结构的极限状态 24 2.2.2 结构的功能函数 24-25 2.2.3 结构的可靠性与可靠指标 25-26 2.3 可靠度的计算方法 26-30 2.3.1 JC 法 26-29 2.3.2 Monte Carlo 模拟抽样法

13、（MC 法） 29-30 2.4 可靠度理论在木结构中的应用 30-36 2.4.1 木结构的抗力与荷载分析 30-33 2.4.2 木结构的功能函数 33-36 2.5 MATLAB 语言 36-37 2.6 小结 37-38 第3章 进口北美规格材强度设计值的计算 38-61 3.1 引言 38 3.2 进口北美规格材强度设计值的可靠度评估 38-42 3.3 进口北美规格材强度设计值的调整建议 42-59 3.3.1 C、C、C、C 等级规格材 42-56 3.3.2 其它等级规格材 56-59 3.4 小结 59-61 第4章 层板胶合木强度设计值的计算 61-73 4.1 引言 61 4.2 胶合木结构技术规范确定强度设计值方法的探讨 61-63 4.3 层板胶合木强度设计值的可靠度评估 63-66 4.4 层板胶合木强度设计值的调整确定 66-72 4.4.1 基于最小可靠指标 66-68 4.4.2 基于平