为促进建筑工业化和住宅产业化，提高框架-支撑结构体系的抗震性能，提出了部分包覆钢-混凝土组合（partially encased composite， PEC）支撑。对3个采用PEC支撑的PEC框架试件和1个采用钢支撑的PEC框架试件进行了低周往复加载试验，研究了各试件的破坏模式、初始刚度、极限承载力、耗能能力等指标。结果表明：PEC框架与PEC支撑之间协同工作性能良好；相较于纯钢支撑，PEC支撑更具优势，初始刚度提升了24%~41%、极限承载力提升了29%~36%，耗能能力提升了7%~17%。基于试验结果，采用ABAQUS软件进行非线性有限元分析，还原了试件的局部屈曲和整体失稳等几何非线性行为，有限元模拟与试验得到的屈服荷载和峰值荷载的误差均小于10%，表明该模型可以较准确地模拟试件的承载特性。有限元分析结果表明：PEC支撑会先于框架梁和柱进入塑性阶段，符合预期的结构破坏顺序；在钢支撑节点腹板两侧浇筑混凝土或增设钢板加劲肋均能有效抑制此处发生应力集中和钢板局部屈曲。

To promote construction industrialization and improve the seismic performance of moment resisting frames with concentrically brace， a new type of partially encased composite （PEC） brace is proposed. Low-cyclic reversed loading tests were carried out on three PEC braces and one steel brace. Failure modes， hysteretic curves， initial stiffness， bearing capacity， ductility and energy dissipation capacity were studied. The results show that the PEC frame and the PEC brace cooperate well as the two structural seismic lines. And compared to the steel brace， three PEC braces are improved in initial stiffness by 24%-41%， bearing capacity by 29%-36% and energy dissipation capacity by 7%-17%， indicating that PEC braces have excellent seismic performance. Based on the results of the experiment， the nonlinear finite element analysis was carried out by ABAQUS software. The geometric nonlinear behaviors such as local buckling and global buckling are observed in finite element models， and the results such as peak load and yield load are in good agreement with the experimental results （the error is within 10%）. The finite element analysis shows PEC braces yield earlier than the PEC frame， which is the expected failure sequence. Additionally， the stress concentration and local buckling of joint of brace can be effectively inhibited by setting concrete or stiffeners on the web.