摘要:
在已有装配式混凝土框架结构的基础上,提出了一种新型装配式不对称混合连接节点(PPEFF节点)。此节点梁纵筋呈不对称设置,仅在梁上部设置耗能钢筋,节点在满足较高施工效率的同时,在梁柱接触面上设置抗剪钢筋,提高了梁柱接触面承载力,保证了结构在节点预应力意外失效后的安全性。为了研究抗剪钢筋的配筋率大小对PPEFF节点抗震性能的影响,结合低周往复荷载试验与ABAQUS有限元软件模拟分析,重点从节点承载能力、耗能性能、刚度退化与自复位能力4个方面分析抗剪钢筋的配筋率大小对节点抗震性能的影响。研究发现:PPEFF节点具有较好的抗震性能,且抗剪钢筋的配筋率增大,能提升节点承载力、刚度、耗能能力。但抗剪钢筋的设置,提高了节点的截面刚度,在一定程度上抑制了节点的自复位能力,从而违背预压装配式节点自复位能力较强的初衷。因此,建议PPEFF节点中抗剪钢筋的配筋率宜设置为0.3%~0.5%。同时提出PPEFF节点梁柱接触面承载力计算式,并通过试验数据与模拟数据验证梁柱接触面承载力计算式的适用性。
Abstract:
Based on the existing prefabricated concrete frame structure, the paper proposed a new type of prefabricated asymmetric hybrid connection joint (PPEFF joint). The longitudinal reinforcement of the beam of this joint was arranged asymmetrically, and only energy-dissipating steel bars were installed on the upper part of the beam. While the joint meets high construction efficiency, shear steel bars were installed on the contact surface of the beam and column, which improved the bearing capacity of the contact surface of the beam and column, so as to ensure the safety of the structure after the accidental failure of the joint prestress. In order to study the influence of the reinforcement ratio of shear steel bars on the seismic performance of PPEFF joints, the paper combined low-cycle reciprocating load test and ABAQUS finite element software simulation analysis, focusing on bearing capacity of joint, energy-dissipating capacity, stiffness degradation and self-restting capacity, etc. The influence of the reinforcement ratio of shear steel bars on the seismic performance of joints was analyzed from these four aspects. Through the research in this paper, it was found that the PPEFF joint had better seismic performance, and the increase in the reinforcement ratio of the shear steel bars would increase the joint bearing capacity, stiffness, and energy dissipation capacity. However, the setting of shear reinforcement improved the section stiffness of the joint and inhibited the self-resetting capacity of the joint to a certain extent, which violated the original intention of the self-resetting capacity of the pre-compressed assembled joint. Therefore, it was recommended that the reinforcement ratio of shear steel bars in PPEFF joints should be set to 0.3% to 0.5%. At the same time, the calculation formula for the bearing capacity of the beam-column contact surface of the PPEFF joint was proposed, and the applicability of the calculation formula for the bearing capacity of the beam-column contact surface was verified through the test data and the simulation data.
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