The eccentric bracing system equipped with vertical links is capable of providing high levels of stiffness, strength and ductility, and therefore, can be efficiently used for seismic retrofit of existing structures. This study aims to investigate the seismic reliability of steel moment-resisting frames retrofitted by this system using a novel combined series–parallel system approach. The seismic response of 4, 8 and 12-storey steel moment-resisting frames (MRFs) are evaluated under a set of design basis earthquakes (DBE) before and after retrofitting intervention. Adopting an engineering demand parameter approach (EDP-Based) for reliability assessment and development of analytical models for the frames using systems consisting of the series–parallel elements are the major distinctions between the present study and the other similar works. To estimate the global reliability of the frames, first, the reliability of each storey is individually derived based on various probable damage levels for the lateral-load resisting members. Then, the seismic reliability of the frame is globally obtained by combining the reliability of each storey for different damage levels in the lateral load-resisting subsystems. The results indicate significant impact of this type of bracing system on improvement of the performance level and load-carrying capacity of the frames along with reduction of the lateral displacements. It is shown that application of the vertical links can reduce the maximum inter-storey drifts by at least 60%, while it leads to at most 17% increase in the base shear. All retrofitted frames exhibited a performance level higher than the Life Safety (LS) when subjected to the DBE hazard level records (earthquakes with return period of 475 years). At the same level of earthquake intensity, in the cases when the drift corresponding to the LS performance level is used as the target, the reliability of the retrofitted frames was improved by more than 90% compared to the original frames for all damage states developed in the vertical links.

配备垂直连杆的偏心支撑系统能够提供高水平的刚度，强度和延展性，因此可以有效地用于现有结构的抗震改造。这项研究的目的是使用新颖的串联-并联组合方法，研究该系统对钢制抗弯框架的抗震可靠性。在进行干预之前和之后，在一组设计基准地震（DBE）下评估4、8和12层钢制抗弯框架（MRF）的地震响应。采用工程需求参数方法（基于EDP）进行可靠性评估，并使用由串并联元素组成的系统开发框架分析模型，这是本研究与其他相似研究之间的主要区别。为了估计框架的整体可靠性，首先，基于抗侧向载荷构件的各种可能的损坏程度，分别得出各层的可靠性。然后，通过组合各层在侧向抗力子系统中针对不同损伤程度的可靠性，整体获得框架的抗震可靠性。结果表明，这种支撑系统对改善框架的性能水平和承载能力以及减少侧向位移具有重大影响。结果表明，竖向连接的应用可以使最大的层间漂移减少至少60％，而基础剪力最多增加17％。在接受DBE危险等级记录（地震的归还期为475年）后，所有翻新的框架都表现出高于生命安全（LS）的性能水平。在地震烈度相同的情况下，如果将与LS性能水平相对应的漂移作为目标，那么对于在2004年开发的所有损坏状态，改装框架的可靠性比原始框架提高了90％以上。垂直链接。