RC连梁损伤控制试验与分析研究

发布时间：2019-06-19 14:52

【摘要】：连梁作为剪力墙体系中主要抗侧力构件,是保证结构整体抗震性能的关键,多次震害结果表明小跨高比连梁通常发生剪切破坏,难以满足实际工程中对其强度和延性的要求。特别是一旦发生损伤,混凝土连梁很难修复,难以实现现代地震工程对功能可恢复性的要求。为了提升剪力墙结构体系的地震韧性,本文将消能减震装置装入连梁中,利用消能装置良好的耗能能力,有效提高连梁的抗震性能。本文首先进行了9个RC连梁试验,研究跨高比、交叉斜筋和楼板对连梁抗震性能的影响,结果表明RC连梁均受弯屈服,但最终破坏模式仍为剪切破坏和弯曲剪切破坏;交叉斜筋可以提高连梁抗剪承载力20%以上,楼板对连梁抗剪承载能力几乎无影响;交叉斜筋和楼板均可以提高连梁受弯屈服承载能力,但对连梁极限变形能力均无明显贡献。连梁的初始有效抗弯刚度集中在0.24EIg到0.3EIg之间,屈服时有效抗弯刚度基本在0.15EIg左右,连梁有效抗弯刚度折减程度大于规范值;随着加载位移增大,连梁和楼板部分相继损伤,不利于震后使用或修复。为了实现RC连梁的损伤控制,本文提出了一种在跨中设置带缝钢板阻尼器的消能连梁,并完成了4个与RC连梁相同跨高比试件的试验,最终破坏模式包含阻尼器弯曲单元撕裂破坏和锚固破坏两种,在弯曲单元撕裂破坏模式下,阻尼器超强系数达到2.5。连梁屈服剪力值与设计值误差在10%以内,阻尼器初始刚度试验值与设计值误差在15%以内,误差原因包含锚固部分变形、螺栓滑移和阻尼器间变形不协调等。同跨高比下消能连梁变形能力、累积耗能能力均大于RC连梁,阻尼器部分变形和耗能占消能连梁80%左右,可以有效控制混凝土部分和楼板的裂缝发展,试验后阻尼器可被快速更换。本文提出了消能连梁简化数值模型,采用简化方法模拟阻尼器的力学行为、混凝土连梁的弯曲和剪切,并在阻尼器之间加入协调单元模拟多组阻尼器之间的变形不协调行为。消能连梁的极限承载力和累积耗能的模拟结果与试验结果误差在10%以内,而初始刚度模拟结果误差达到20%以上,原因在于试验边界条件和数值模拟边界条件的区别所致。本文进一步对影响阻尼器屈服承载力和刚度的关键参数——跨度比、变形比和强度比——进行参数分析,结果表明过高或过低的取值对连梁承载力、耗能能力和阻尼器进入屈服时转角均不利,建议三个参数分别在0.3~0.4、0.6~0.7和0.6~0.7范围内选用。
[Abstract]:As the main anti-lateral force component in the shear wall system, the continuous beam is the key to ensure the overall seismic performance of the structure. In particular, once the damage occurs, the concrete connecting beam is difficult to repair, and the requirement of the modern seismic engineering to the function recoverability is difficult to realize. In order to improve the seismic toughness of the shear wall structure system, the energy dissipation and shock-absorbing device is put into the continuous beam, and the seismic performance of the continuous beam can be effectively improved by utilizing the good energy dissipation capability of the energy dissipation device. In this paper, nine RC beam-beam tests are carried out, and the effect of the cross-height ratio, the cross-diagonal bar and the floor slab on the seismic performance of the continuous beam is studied. The results show that the RC beams are both bent and yielding, but the ultimate failure mode is still the shear failure and the bending shear failure. The cross-inclined rib can improve the shear bearing capacity of the continuous beam by more than 20%, and the slab has little influence on the shear-bearing capacity of the connecting beam; the cross-inclined rib and the floor slab can improve the bending yield bearing capacity of the connecting beam, but have no obvious contribution to the limit deformation capability of the connecting beam. The initial effective bending stiffness of the continuous beam is in the range of 0.24 EIg to 0.3EIg, the effective bending stiffness at the time of yield is about 0.15 EIg, the effective bending stiffness of the continuous beam is greater than the specification value, and as the loading displacement is increased, the continuous beam and the floor part are damaged after the earthquake, which is not conducive to the post-earthquake use or repair. In order to control the damage of RC beam, a kind of energy dissipation and connecting beam with joint steel damper is proposed in this paper, and four test pieces with the same cross-height ratio as RC beam are completed, and the final failure mode includes two kinds of rupture and anchoring failure of the bending unit of the damper. In the break-up mode of the bending unit, the super-strong coefficient of the damper reaches 2.5. The error of the initial stiffness test value of the damper and the design value error is within 15%, and the error reason includes the deformation of the anchoring part, the bolt slip and the non-coordination of the deformation between the dampers, etc. The energy dissipation capacity of the energy dissipation and connecting beam at the same span is greater than that of the RC beam, the deformation and energy consumption of the damper account for about 80% of the energy dissipation and connecting beam, and the crack development of the concrete part and the floor slab can be effectively controlled, and the damper can be quickly replaced after the test. In this paper, a simplified numerical model of energy dissipation continuous beam is proposed, and the mechanical behavior of the damper and the bending and shearing of the concrete connecting beam are simulated by a simplified method, and the coordination unit is added between the dampers to simulate the deformation incoordination between groups of dampers. The simulation results of the ultimate bearing capacity and the accumulated energy consumption of the energy dissipation and connecting beam are within 10% of the experimental results, and the error of the initial stiffness simulation results is more than 20%, due to the difference between the test boundary conditions and the numerical simulation boundary conditions. The key parameters _ span ratio, deformation ratio and strength ratio of the yield bearing capacity and the stiffness of the damper are further analyzed. The results show that the value of too high or too low is unfavorable to the bearing capacity of the continuous beam, the energy dissipation capacity and the angle of the damper entering the yield. It is suggested that the three parameters are selected in the range of 0.3-0.4, 0.6-0.7 and 0.6-0.7, respectively.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU352.11;TU375

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