钢筋混凝土平面框架节点单元BCJ⁃5N

本文基于四根刚臂梁结合12个外接一维单元建立了钢筋混凝土框架节点单元，单元具有5个节点15个 自由度，称之为“BCJ-5N”单元．每个节点具有3个自由度，与普通梁单元一致，从而确保本单元适合于同普 通一维梁柱单元一起进行钢筋混凝土结构平面非线性分析．单元考虑了梁受力钢筋在框架节点内的黏结滑移作 用，并通过钢筋混凝土梁正截面强度设计建立了梁端弯矩与截面转角关系的骨架曲线，结合Lowes加载卸载模 型，组成了完整的静力、动力分析的框架节点单元，并将其移植到 ABAQUS通用分析平台上，通过对两跨三 层钢筋混凝土框架结构的滞回分析和三跨三层钢筋混凝土框架结构的动力分析两个算例，验证了本模型适合于 进行循环荷载和动力荷载作用下平面框架结构非线性响应分析．

Beam-Column Joint Element BCJ-5N for Reinforced Concrete Plane Frame

Based on four rigid beams combined with 12 one-dimension elements, a model is developed to represent the response of reinforced concrete beam-column joints under reserved cyclic and dynamic loading. The model is implemented as a five-node fifteen-degree-of-freedom element, named as BCJ-5N. The element has three degrees of freedom for each node, coinciding with the typical beam element, and is therefore appropriate for use with typical hysteretic beam-column line elements in twodimensional nonlinear analysis of reinforced concrete structures. The element includes bond-slid relation of beam bars. The bone curve of the moment-versus-rotation relation at the beam ends is established. Based on the Lowes' model for the unload-reload loading path, the complete frame joint elements for both static and dynamic analysis are established, and implemented into ABAQUS. Through two simulation examples, i.e., the hysteresis analysis of a two-span three-floor reinforced concrete frame, and the dynamic analysis of a three-span three-floor reinforced concrete frame, it is indicated that the proposed model is appropriate for use in simulating response of building joints under cyclic and dynamic loading