蠕变对弦支胶合木穹顶结构受力性能的影响研究

发布时间：2018-03-24 15:09

本文选题：弦支胶合木穹顶结构　切入点：静力性能　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：弦支胶合木穹顶结构是基于单层胶合木网壳和张拉整体结构的一种合理的新型大跨度钢木混合结构。下部张拉体系提高了结构的整体刚度和稳定性,并且改善了上部胶合木网壳的受力,减小了结构周边支承的作用。由于木材的蠕变特点突出,弦支胶合木穹顶结构表现出与弦支钢穹顶结构不同的结构受力性能,本文重点研究胶合木材料的蠕变对结构静力性能的影响和对弦支胶合木穹顶结构施工过程中结构性能的影响,力图寻找合适的施工方法和确定结构的预应力张拉程序。主要工作如下:首先以弦支胶合木穹顶结构的典型算例为例,将该结构和相同几何参数的单层球面网壳的静力性能进行对比,研究弦支胶合木穹顶结构的静力性能。分析结果表明,与单层网壳结构相比,弦支穹顶结构可推迟结构发生蠕变屈曲的临界时间。结构的变形随蠕变的发展变化较为明显。蠕变对结构的影响主要体现在节点竖向位移上,结构的最大节点竖向位移在第50年可达到初始位移的3.8~4.6倍。蠕变对结构杆件内力也有一定程度的影响,网壳肋杆内力有一定程度的减小,环杆内力有一定程度的增大。蠕变对支座反力影响甚微,支座反力几乎不随蠕变变形的发展而改变。然后,对不同跨度的弦支胶合木穹顶结构进行考虑蠕变情况下的参数分析。通过改变矢跨比、撑杆高度、布索方式和预应力大小等结构参数,研究了结构参数对结构的静力性能的影响规律。主要包括节点竖向位移、支座反力和杆件内力等方面的对比分析,给出考虑材料蠕变情况下对于不同结构参数的合理的建议取值范围,40~60m跨度的弦支胶合木穹顶结构矢跨比取1/8~1/6较好,环索预应力取值在200~250MPa能较好改善结构受力,下部布索方式宜连续。最后,对弦支胶合木穹顶结构的施工张拉过程进行了模拟。对比分析了不同张拉顺序和不同张拉方案对施工过程的影响,并进一步分析了蠕变对施工张拉过程的具体影响。分析结果表明,由外圈到内圈张拉环索并考虑外三环环索由外到内依次超张拉25%、15%和10%的施工方案较为合理,希望可为以后弦支胶合木穹顶结构的工程施工提供借鉴和参考。
[Abstract]:The chord supported glued wood dome is a reasonable new type of large-span steel-wood hybrid structure based on single-layer glued wood reticulated shell and tensioning integral structure. The lower tensioning system improves the overall stiffness and stability of the structure. It also improves the force of the upper glued wood reticulated shell and reduces the function of the peripheral support of the structure. Because of the outstanding creep characteristics of the wood, the structure of the plywood dome is different from that of the steel dome. This paper focuses on the influence of creep of glued wood material on the static performance of the structure and on the structural performance during the construction of the plywood dome structure. The main work of this paper is as follows: firstly, taking the typical example of the plywood dome structure as an example, we try to find a suitable construction method and determine the prestress tensioning program of the structure. The static performance of this structure is compared with that of single-layer spherical reticulated shell with the same geometric parameters, and the static performance of the chord supported glued wood dome is studied. The results show that compared with the single-layer reticulated shell, the static behavior of the structure is compared with that of the single-layer reticulated shell. The critical time of creep buckling of the structure can be delayed. The deformation of the structure changes obviously with the development of creep. The influence of creep on the structure is mainly reflected in the vertical displacement of the joints. The maximum vertical displacement of the structure can reach 3.84.6 times of the initial displacement in the fiftieth year. The creep also has a certain degree of influence on the internal force of the structural member, and the internal force of the reticulated shell ribbed rod decreases to a certain extent. The internal force of the ring rod increases to a certain extent. The creep has little effect on the reaction force of the bearing, and the reaction force of the bearing almost does not change with the development of creep deformation. The parameter analysis of the chord supported glued wood dome structure with different span is carried out under the condition of considering creep. By changing the structural parameters such as the ratio of rise-span, the height of bracing rod, the way of cabling and the size of prestress, etc. The influence of structural parameters on the static behavior of the structure is studied, including the comparative analysis of the vertical displacement of the joints, the reaction force of the bearing and the internal force of the member, etc. Under the condition of considering the creep of materials, the reasonable suggestion for different structural parameters is given. The rise-span ratio of the chord supported plywood dome structure with 40m span and the ratio of 1 / 8 / 1 / 6 is better, and the prestress value of the ring cable can better improve the stress of the structure in 200~250MPa. In the end, the construction tension process of the chord plywood dome structure is simulated. The effects of different tension sequences and different tensioning schemes on the construction process are compared and analyzed. The concrete influence of creep on the construction tensioning process is further analyzed. The results show that the construction scheme from outer ring to inner ring tensioning cable and taking into account the outer three ring cables overstretch 25% and 10% respectively from outside to inside is more reasonable. It is hoped that it can be used for reference and reference for the engineering construction of the chord branch glued wood dome structure in the future.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU399

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