钢筋混凝土梁板子结构在边柱失效下的连续倒塌试验研究

发布时间：2018-08-08 18:00

【摘要】：现有钢筋混凝土(RC)框架结构的抗连续倒塌研究主要针对梁-柱框架骨架,关于楼板对结构抗连续倒塌性能影响的试验研究和理论分析相对缺乏。实际上梁和楼板组成的楼盖系统作为一个整体结构体系共同抵抗连续倒塌,楼板对框架连续倒塌的破坏机理、失效模式、以及抗力/变形发展规律均产生重要影响。本文针对RC框架结构边柱失效这一典型连续倒塌失效模式开展了试验和理论研究,主要工作包括:(1)设计了5个1/3缩尺的试件,包括4个梁-板子结构试件和1个纯框架梁试件,通过静力加载试验研究了RC框架结构边跨区域楼盖系统的连续倒塌破坏过程。(2)分析了试件的抗力/变形和关键截面应变的发展规律,结合典型试验现象,研究了边跨区域梁-板子结构的倒塌破坏机理以及不同倒塌阶段的抗倒塌机制。在小变形阶段,边跨区域楼盖系统主要依靠梁-板的抗弯能力以及压拱效应提供倒塌抗力,其中抗弯贡献主要来自于两个方向(边缘方向和垂直边缘方向)的框架梁及其附近一定宽度内的楼板;受边跨区域约束条件和不均匀变形的影响,压拱效应仅发生在靠近边缘的梁和部分楼板。在大变形阶段,楼盖系统的倒塌抗力由梁-板内钢筋的悬链线拉力提供,且受不均匀变形的影响,靠近边缘框架梁的板内钢筋的拉力贡献更大。(3)对比分析了纯框架梁试件与梁-板子结构试件,发现楼板显著提高了框架梁的抗连续倒塌承载力,梁-板子结构试件的梁机制峰值承载力比相同截面尺寸的梁试件提高约1.5倍,悬链线峰值承载力提高约1倍。(4)研究了不同设计参数(板厚、梁高以及抗震设防烈度)对梁-板子结构连续倒塌抗力的影响。研究表明,梁机制承载力主要受梁截面高度及配筋率影响,增大梁高可以显著提高梁机制峰值承载力;悬链线机制承载力主要受截面配筋面积影响,与截面尺寸无关,增大梁内配筋面积可以显著提高悬链线峰值承载力。(5)提出了边跨区域梁-板子结构悬链线机制承载力的理论计算方法,与试验结果对比,证明了该方法具有良好的计算精度。利用试验结果检验了现有连续倒塌规范中的拉结强度法,指出了现有设计方法的不足。提出了改进的拉结强度法,试验验证表明该方法安全可靠且具有一定的承载力储备,适用于工程设计。
[Abstract]:The research on the continuous collapse of reinforced concrete (RC) frame structure is mainly focused on the beam-column frame skeleton. The experimental study and theoretical analysis on the influence of floor slab on the continuous collapse performance of the structure are relatively lacking. In fact, the floor system composed of beams and slabs, as an integral structure system, has an important influence on the failure mechanism, failure mode, and resistance / deformation development of the frame as a whole. In this paper, an experimental and theoretical study has been carried out on the typical continuous collapse failure mode of RC frame structure. The main works are as follows: (1) five specimens with 1 / 3 scale are designed, including four beam-plate substructure specimens and one pure frame beam specimen. The continuous collapse and failure process of RC frame structure with side span area floor system is studied by static loading test. (2) the development law of resistance / deformation and critical cross section strain of RC frame structure is analyzed, combined with typical experimental phenomena. The collapse failure mechanism of beam-plate structure with side span and the mechanism of anti-collapse in different collapse stages are studied. In the small deformation stage, the lateral span area floor system mainly depends on the beam-slab bending ability and the compression arch effect to provide the collapse resistance. The flexural contribution mainly comes from the frame beam with two directions (edge direction and vertical edge direction) and the floor slab in a certain width around it, which is affected by the constraint condition of the side span region and the inhomogeneous deformation. Arch compression effect only occurs near the edge of the beam and part of the floor. In the large deformation stage, the collapse resistance of the floor system is provided by the catenary tension of the beam-slab reinforcing bar, and is affected by the uneven deformation. The tensile force contribution of the steel bar near the edge frame beam is greater. (3) comparing the pure frame beam specimen with the beam-plate structure specimen, it is found that the floor slab significantly improves the continuous collapse bearing capacity of the frame beam. The peak bearing capacity of beam mechanism of beam-plate structure specimen is about 1.5 times higher than that of beam specimen with the same cross section size, and the peak bearing capacity of catenary is about 1 times higher than that of beam specimen with the same cross-section size. (4) different design parameters (plate thickness) are studied. The influence of beam height and seismic fortification intensity on continuous collapse resistance of beam-plate structure. The results show that the bearing capacity of the beam mechanism is mainly affected by the beam section height and the reinforcement ratio, the peak bearing capacity of the beam mechanism can be significantly increased by increasing the beam height, and the bearing capacity of catenary mechanism is mainly affected by the section reinforcement area, which has nothing to do with the section size. The peak bearing capacity of catenary can be significantly increased by increasing the reinforcement area of beam. (5) the theoretical calculation method of catenary mechanism of beam-plate structure with side span is proposed, and compared with the experimental results, it is proved that this method has good calculation accuracy. The test results are used to test the tensile strength method in the existing continuous collapse codes, and the shortcomings of the existing design methods are pointed out. An improved tensile strength method is proposed. The test results show that the method is safe and reliable and has a certain bearing capacity reserve, which is suitable for engineering design.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375;TU312.3

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