【作者】 赵杰林；

【导师】 白绍良； 傅剑平；

【作者基本信息】 重庆大学 ， 结构工程， 2003， 硕士

【摘要】 连梁是联肢剪力墙结构中的重要构件，它是墙肢之间传力的纽带，其线刚度是影响联肢墙侧向刚度以及墙肢中内力的关键因素之一，而且是抗震联肢墙结构耗散地震能量的首选部位。一方面由于建筑上的需要，小跨高比连梁时有所见；另一方面，在框架-剪力墙和框架-核心筒结构中，因其中的剪力墙和核心筒承担大部分水平荷载，故有必要选用跨高比偏小的连梁以保证所需的侧向刚度。但是，小跨高比连梁属于两端被约束，反弯点在跨中的反对称弯曲深梁，其受力和变形规律不同于一般深梁。试验研究表明，在抗震联肢墙中对这类连梁若再用常规框架梁的抗震设计方法进行设计已无法避免其过早发生剪切破坏，从而无法满足结构对它的延性要求。至今国内外仍未找到一种既方便施工，又能保证剪切失效出现在连梁达到所需的位移延性之后的有效配筋方案。在刚完成的我国新一轮结构设计规范修订中，小跨高比连梁的抗震设计方法是被关注的重点问题之一，并在《建筑抗震设计规范》、《混凝土结构设计规范》和《高层建筑混凝土结构技术规程》的协调会上作过认真讨论，但因试验研究工作尚不够充分，未能取得一致意见。在这一背景下，《高层建筑混凝土结构技术规程》（JGJ3-2002）为了满足工程设计需要，对小跨高比连梁在没有充分试验结果的情况下，仍采用降低最大作用剪力和提高箍筋用量的设计方法（虽然这种方法已被国外试验证明在跨高比小于1.50的连梁中是肯定不能保证延性要求的），而《混凝土结构设计规范》（GB50010-2002）则把这部分内容继续留作空缺。 针对工程设计中这一急待解决的重要问题，本论文作者所在的研究组对小跨高比连梁进行了系列试验研究。其中首先通过硕士研究生张彬彬的试验研究工作，进一步证实《高层建筑混凝土结构技术规程》（JGJ3-2002）提出的设计方法不能满足抗震基本要求；同时查明，国内外已提出的某些施工可以接受的改进配筋方案仍未达到较满意的延性性能。在总结已有配筋方案的基础上，本论文作者所在研究组提出了一种工程适用性好的配筋方案，即在传统配筋基础上加设对角斜筋和上、下两组“L”形筋组成的菱形斜筋的方案。经硕士研究生曹云峰四个接近足尺构件的低周交变加载试验，证实这种配筋形式小跨高比连梁（跨高比为1.0）具有良好的延性及塑性耗能能力。 为了进一步深入研究工作，本论文的工作集中于以下两个方面： ①通过5个接近足尺构件的试验进一步查明：1)抗剪能力上限提高到V_u=0.2f_cbh₀或更高的可能性；2)连梁箍筋和纵向构造筋同时减小到最小构造配筋量的可能性；3)不同对角斜筋与菱形斜筋比例对这类小跨高比连梁性能的影响；重庆大学硕士学位论文4)混凝土强度等级对这类小跨高比连梁性能的影响;5)将这一配筋方案应用到跨高比为0.8和1.25情况下的有效性。 ②国外学者近年来提出，对于剪切效应明显的“非贝努利区”或“干扰区”可以用较简单的“压杆一拉杆模型”（the strut一and一tie model）作为受力分析的有效“宏观模型”（macro model）。小跨高比连梁属于这类区域。但本文连梁配筋构造特殊，因此，本文任务在于尝试对这种配筋方案的深连梁用上述模型来模拟其受力性能。 试验结果表明:①在抗剪能力上限提高到vu二0.2必h0和箍筋与纵向构造筋减至最低构造数量的条件下，这类配筋方式的连梁仍具有不小于5 .0的位移延性，且耗能能力良好:②在跨高比为0.8一1.25的范围内，连梁都依然保持上述良好性能;③配筋比例应以对角斜筋为主，一组“L”形斜筋用量与单向对角斜筋用量的比值宜控制在0.35一0.55的范围内;④通过对曹云峰的试验与本文试验的综合分析，表明CZ于C45的混凝土强度等级都是可用的，未发现混凝土强度在这一范围内偏高或偏低时可能带来什么不利影响。 对比分析结果表明，本文所提出的适用于这类配筋方式的压杆一拉杆模型能对连梁受力性能作有效模拟。 这类连梁的设计方法宜在进一步积累跨高比为1.25一2.5的连梁试验结果后统一提出，菱形斜筋在连梁中的受力机理和作用也有待用更多试验来验证。更多还原

【Abstract】 Coupling beams are important elements in coupled walls. They are ligaments for passing force between single shear walls, and their linear stiffness is one of the key factors of affecting lateral stiffness of coupled walls and the internal forces in coupled walls , furthermore they are the first position for earthquake energy dissipation in seismic coupled walls. On the one hand, coupling beams with small aspect ratio are sometimes used due to architectural requirement; on the other hand, because shear walls in frame-shear walls and frame-tube structures bear most horizontal forces, coupling beams with small aspect ratio need be chosen to guarantee lateral stiffness required. However, for small span-to-depth ratio coupling beams are counter flexural deep beams restrained at their two ends and points of contraflexure at the center of the span, the rules of their carrying forces and deformation are not like common deep beams. If these kinds of coupling beams in seismic coupled walls are designed with seismic design methods of the normal frame beams, test investigation shows that they can’t avoid to occur shear failure very early, so that their ductility demand can’t be satisfied to the structure. So far domestic and foreign researches have not yet found out an effective reinforcement arrangement scheme for convenient construction and guaranteeing the occurrence of shear failure after coupling beams attaining displacement ductility required. Seismic design method of coupling beams with small aspect ratio was one of important problems catching notice at the newly revising structure design codes just completed, and it was discussed seriously at the harmonizing meeting of China Code for Seismic Design of Structures, China Code for Design of Concrete Structure and The Code for Design of Reinforced Concrete High-rise Structure. However, because of the insufficiency of experimental research, unanimous opinions were not obtained. At this background, though coupling beams with the small ratio of the span to depth have no sufficient test results, in order to satisfy the needs of engineering design, The Code for Design of Reinforced Concrete High-rise Structure (JGJ3-2002 ) still adopt the design method of decreasing the maximum shear force and increasing the quantity of stirrups. But in China Code for Design of Concrete Structures (GB 50010-2002) the content of seismic design methods for these kinds of coupling beams continue to be blank.Aiming at this important problem to be urgently settled in engineering design, the research group in which the author of this thesis is have carried out a series of testinvestigations on coupling beams with small aspect ratio. Firstly, the Master Zhang Binbin’s tests further verified that the design methods brought forward by The Code for Design of Reinforced Concrete High-rise Structure (JGJ3-2002) can not satisfy basic seismic requirement. At the same time, our research group find that some acceptable improved reinforcement arrangement scheme in domestic and foreign researches can not attain satisfying ductility performance.At the basis of the summary of reinforcement arrangement scheme already put forward, our research group brings forward a reinforcement arrangement scheme having good applicability in engineering, namely the reinforcement arrangement scheme of adding the diagonal bars and rhombic inclined bars on the basis of traditional reinforcement. The long period cyclic tests of four specimens near to sufficient dimension made by the Master Cao Yunfeng prove that the reinforcement arrangement scheme can obtain favorable displacement ductility and plastic energy dissipation capacity for the coupling beams with the small aspect ratio of 1.0.To go deep into the research further, this thesis concentrates on the two aspects following:(1)The author of this thesis carries out the long period cyclic test of five specimens near to sufficient dimension to further verify: 1) the probability that the upper limit of shear-resistant ability increases to Vu = 0.2fcbh0 or higher;更多还原