【作者】 曾毅恒；

【导师】 赵基达； 宋涛；

【作者基本信息】 中国建筑科学研究院 ， 结构工程， 2008， 硕士

【摘要】 张弦拱(拱架)是拱(拱架)与悬索通过撑杆连接组合而成的新型结构体系,索与拱(拱架)的水平反力互为平衡,结构轻巧,具有优良的受力性能。自上世纪90年代以来,张弦拱(拱架)已开始应用于多项大跨度公共建筑。随着此类结构应用的增多,其对应的结构性能研究需要进一步的深化。目前针对张弦拱(拱架)所做的研究主要是以有限元分析为基础,通过静力、动力的分析计算,得出一些有用的结论。但是,目前对张弦拱(拱架)缺乏系统地理论研究,对该结构体系的受力机理还缺乏足够的了解,没有一个连续化的分析方法与计算公式。这不仅使得一些通过有限元计算分析所得到的结论缺乏理论上的支持,也不利于张弦拱(拱架)的工程设计。本文从张弦拱(拱架)的受力机理出发,通过理论分析与模型试验,系统地研究了张弦拱(拱架)的静力、动力性能,并对张弦拱(拱架)在设计、施工中所遇到的问题提出了相关建议。本文的工作主要包括以下几个方面:概述了张弦梁体系的发展过程,通过其构件组成,几何形状与受力特征对张弦梁进行了分类,介绍了国内外研究人员在张弦拱(拱架)的相关领域所进行的工作,阐述了研究这类结构的相关意义,并介绍了目前国内外著名的张弦拱(拱架)结构工程。本文的研究工作主要针对张弦拱(拱架)展开。通过引入各种假设,将张弦拱(拱架)简化为一连续化体系,推导其在均布荷载作用下以及活荷载半跨分布下的位移、内力计算公式、及预应力张拉阶段的位移、内力计算公式。根据分析结果提出了预应力、结构矢跨比、垂跨比以及拱(拱架)截面抗弯刚度的合理取值建议。进行了模型试验以验证理论分析公式的正确性,并深化了对此结构的认识。模型试验的内容包括:张弦拱(拱架)张拉阶段的位移、内力反应;在均布荷载作用下模型的位移、内力反应;在活荷载半跨分布下模型的位移、内力反应;在均布荷载作用下模型的极限承载能力检验。试验目的主要包括:将试验结果、有限元分析、简化计算公式进行对比,确定有限元方法以及简化公式的适用性;从试验结果中总结出张弦拱(拱架)的受力特征,并通过简化计算公式进行解释,提出理论依据;对张弦拱(拱架)的破坏机理以及对应的极限承载力进行考察。以连续化假设为基础,推导了张弦拱(拱架)自振频率的简化计算公式。同时,进行了模型试验并采集了张弦拱(拱架)模型的前4阶自振频率及其对应振型,将试验实测结果与有限元分析以及简化公式计算相对比,验证有限元方法和简化计算公式的适用性。通过对试验结果的分析,总结出张弦拱(拱架)的自振特征,并利用简化计算公式对试验所得出的结果从理论上进行了解释与论述。更多还原

【Abstract】 Beam string structure, which is formed with arch and string with the connection of members in compression, is a new type space-structure. For beam string structure the horizontal forces of arch and string are equal to each other, so the structure is light and handy, and has good behavior under different load conditions. Since the 1990s, beam string structure has been widely used in many public buildings with long span. With the number of beam string structures increased, the performance of this structure need to identified more clearly. Now, with FEM method, researchers has made static analysis、dynamic analysis, got some useful conclusions. Although FEM method plays an important in research, bearing mechanism of beam string structure is not very clear, a simplified formula based on continuous hypothesis has not been derived yet. Without simplified formula, it is very hard to explain the conclusions got by FEM method theoretically. Meanwhile, in conceptual design, designers can not choose the structure parameters easily, or make judgments for some important behavior.This dissertation is devoted to the force mechanic of beam string structure. By theoretical analysis and modal experiment, we analyze the static behavior and the dynamic behavior systematically. For the problem raised in designing and construction, we also make some useful suggestion. This dissertation contains following parts:Generalize the developing process of beam string structure, classify different types of beam string structure by components geometry and mechanics characteristics, introduce research productions in related field, expound the meanings of research, and introduce some famous beam string structures.The main research work focus on the beam string structure. By making continuous hypothesis, beam string structure can be treated as a continuous system. We deduct the simplified formula to calculate displacement and force under uniformly distributing load and live load half span distribution; the simplified formula to calculate displacement and force corresponding the tensioning stage, and propose the reasonable value of prestress, rise span ratio, height span ratio and moment of inertia of arch. Design modal experiment to deep the understanding of beam string structure. The process of modal experiment contains follow parts: the displacement and force response in tensioning stage; the displacement and force response under uniformly distributing load; the displacement and force response under live load half span distribution; the ultimate bearing capacity experiments under uniformly distributing load. The purpose of these experiments is: compare different results(modal experiment、FEM method、simplified formula), conclude the suitability of FEM method and simplified formula; conclude the mechanics characteristic by analyzing the experiment result, and explain these conclusions by the simplified formula; analyze the failure mechanism and the ultimate bearing capacity of beam string structure.Based on the continuous hypothesis, deduct the simplified formula of the free vibration. Meanwhile, make modal experiment and test the former 4 orders natural frequency, compare different result(modal experiment、FEM method、simplified formula), conclude the suitability of FEM method and simplified formula. By analyze the experiment result, conclude the free vibration characteristics of beam string structure, explain and expand the conclusion by simplified formula.更多还原