竹质构件耐水性及其桥梁结构状态监测与评估

发布时间：2018-01-19 06:24

本文关键词： 竹质构件耐水性监测与评估胶层开裂承载能力衰变　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文依托国家林业公益性行业科研专项重大项目“大跨度竹质工程构件制造关键技术研究与示范”(201204701)。在21世纪“低碳、环保、经济和可持续发展”的背景下,随着重组竹技术的深入与完善,竹材来源广泛,以及其质轻、高强、韧性好、生态环保等优点突出,现代竹质桥梁将广泛修建,不仅适用于人行景观桥,还适用于部分车形桥,得到了空前发展。然而,针对竹(木)桥梁监测与评估处于初始研究阶段,本文具有重要的研究意义和必要性。本文研究了重组竹构件(抗剪、弯、压试件)的耐水性和层间胶开裂对竹梁强度、刚度的影响,并在此基础上,结合丰都某竹桥的具体特征,建立了该桥的监测与评估系统,讨论了监测系统中监测指标的选择、采集与评定,运用AHP-变权理论的综合评估方法来评定结构状态等级,为管养决策提供依据。本文主要研究如下:①以重组竹构件为研究对象,研究了抗剪、抗压及抗弯试件的耐水性试验,分析得到不同构件的破坏形式,其含水率随浸水时间的吸水方程,以及力学特性随浸水时间或含水率变化的耐水性衰变方程。②层间胶开裂是重组竹材主要缺陷之一。利用大型通用有限元软件abaqus模拟10种胶开裂形式对抗弯竹梁的影响分析,从而得到不同位置不同胶开裂长度对其强度、刚度及承载能力的衰减变化。③基于监测系统与传感器的概念和相关准则,建立了竹质桥梁结构的监测系统,提出了监测系统中数据采集方法,并对监测指标进行分类和评定,其中不能直接评定的指标选用适当函数进行无量纲化处理。根据丰都某竹桥的服役环境及结构特征,确定了几项现场监测项目。④基于AHP-变权理论的综合评估体系框架,建立了丰都某竹桥状态评估的层次结构模型,运用变权理论,整体反映所有构件的工作状态,特别是权重较小构件,即次要构件,使评价结果更加符合实际、更加合理。
[Abstract]:This paper relies on the national forestry public welfare industry special scientific research project "the research and demonstration of key technology of large-span bamboo engineering component manufacturing" (201204701). In 21th century, "low carbon, environmental protection". Under the background of economy and sustainable development, with the deepening and perfection of reconstituted bamboo technology, bamboo has a wide range of sources, as well as its advantages of light weight, high strength, good toughness, ecological environmental protection and so on, modern bamboo bridges will be widely built. It is not only suitable for pedestrian landscape bridges, but also suitable for some vehicle-shaped bridges. However, the monitoring and evaluation of bamboo (wood) bridges is in the initial stage of research. This paper is of great significance and necessity. This paper studies the effects of water resistance of reconstituted bamboo members (shear, bending and compression specimens) and interlayer adhesive cracking on the strength and stiffness of bamboo beams. According to the specific characteristics of a bamboo bridge in Fengdu, the monitoring and evaluation system of the bridge is established, and the selection, collection and evaluation of monitoring indexes in the monitoring system are discussed. The comprehensive evaluation method of AHP- variable weight theory is used to evaluate the structural state grade and to provide the basis for the management decision. This paper mainly studies the shearing resistance of the reconstituted bamboo components as follows: 1. Water resistance tests of compressive and flexural specimens were carried out. The failure modes of different components were analyzed and the water absorption equation of water content with immersion time was obtained. One of the main defects of reconstituted bamboo is the water-resistant decay equation .2 of mechanical properties, which varies with soaking time or moisture content. Ten kinds of adhesive cracking shapes are simulated by abaqus, a large scale general finite element software. The effect of the formula on the bending bamboo beam is analyzed. Thus, the attenuation and variation of strength, stiffness and bearing capacity of different adhesive crack length in different positions are obtained. 3. Based on the concept of monitoring system and sensor and related criteria, the monitoring system of bamboo bridge structure is established. The method of data acquisition in the monitoring system is put forward, and the monitoring indexes are classified and evaluated. The indexes which can not be directly evaluated are dimensionless according to the service environment and structural characteristics of a bamboo bridge in Fengdu. Based on the AHP- variable weight theory, a hierarchical structure model of a bamboo bridge state evaluation in Fengdu is established, and the variable weight theory is used. The whole reflects the working state of all the components, especially the smaller weight components, that is, the secondary components, which makes the evaluation results more realistic and reasonable.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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