Rebar slippage in reinforced concrete (RC) elements results in concrete expansion, large cracks, and consequently, early deterioration of strength as well as premature stiffness degradation, particularly in the inelastic energy dissipating zones. Although design standards prescribe different minimum concrete compressive strength, seismic evaluation and retrofit standards, and guidelines permit the use of provisions regarding bond strength and bar slippage issues regardless of the minimum specified concrete strength postulated in design standards. To better understand the seismic behavior of special moment-resisting (SMR) beams exhibiting fixed-end rotation resulting from the rebars inelastic elongation and slip, quasi-static cyclic tests were performed on eight full-scale SMR beams. The chosen beams have longitudinal reinforcement ratios of 0.84% (Type-1) and 1.26% (Type-2) with a shear-span to depth ratio of 6.14 and detailed following the provisions of ACI-318-19. Two specimens were prepared for each reinforcement ratio using concrete with compressive strengths equal to 2000 psi (14 MPa, M14) and 3000 psi (21 MPa, M21). The specimens were tested under cyclic displacement protocols, exhibiting flexure yielding that was followed by diagonal shear cracking and, ultimately, bond failure at the beam–block interface. It is even though the beams fulfill the requirements of ACI 318-19 for steel bars embedment and end hooks for anchorage. Force–displacement hysteretic response curves were obtained revealing pinching behavior in the cyclic response. Both types of beams deformed up to maximum chord rotations of 5.22% and 5.73% in case of beams with M14 and M21 concrete, respectively, and experienced cover concrete crushing at the compressed toe. Representative numerical models were assembled implementing fiber-section force-based inelastic beam elements. Additionally, lumped inelastic rotational springs were added to the model for fixed-end rotation. A tri-linear moment-rotation hysteretic response curve has pinching behavior was used to simulate the reduction in re-loading stiffness. This was verified with the measured response of tested beams; excellently simulates the hysteretic response. Moreover, to examine the seismic response of a total structural system regarding these findings, several response history analyses were performed on capacity-designed five-story frames to demonstrate the importance of modeling beam element fixed-end rotation for predicting the story drift demands subjected to different earthquake ground motions. It was found that despite the bar-slip phenomenon the beams developed their yield capacities; however, the response of the frame was subjective depending on the characteristics of input motions, particularly the valleys and hills of the spectral shape.

钢筋混凝土（RC）单元中的钢筋滑移会导致混凝土膨胀，大裂缝，并因此导致强度的早期降低以及刚度的过早降低，特别是在非弹性耗能区。尽管设计标准规定了不同的最小混凝土抗压强度，但抗震评估和翻新标准以及准则允许使用关于粘结强度和钢筋滑移问题的规定，而与设计标准中假定的最小规定混凝土强度无关。为了更好地理解由钢筋的非弹性伸长和滑移引起的具有固定端旋转的特殊抗弯矩（SMR）梁的抗震性能，对8个全尺寸SMR梁进行了准静态循环试验。所选梁的纵向钢筋比率为0。84％（Type-1）和1.26％（Type-2）的剪切跨度与深度之比为6.14，并按照ACI-318-19的规定进行详细说明。使用抗压强度等于2000 psi（14 MPa，M14）和3000 psi（21 MPa，M21）的混凝土，针对每种配筋率准备了两个试样。样品在循环位移方案下进行了测试，表现出弯曲屈服，接着是斜向剪切开裂，最终在梁-块界面处发生粘结破坏。即使梁满足ACI 318-19的钢筋嵌入和锚固端钩的要求。获得了力-位移滞后响应曲线，揭示了循环响应中的收缩行为。在使用M14和M21混凝土的情况下，两种类型的梁的最大弦旋转量分别达到5.22％和5.73％，并在压缩脚趾处经历了覆盖混凝土的破碎。组装了具有代表性的数值模型，以实现基于纤维截面力的非弹性梁单元。此外，将集总的非弹性旋转弹簧添加到模型中以进行固定端旋转。具有收缩行为的三线性矩-旋转磁滞响应曲线被用来模拟重新加载刚度的减小。测量的测试光束响应证实了这一点。出色地模拟了磁滞响应。此外，要针对这些发现检查整个结构系统的地震响应，在容量设计为五层的框架上进行了几次响应历史分析，以证明建模梁单元固定端旋转对于预测不同地震地面运动引起的故事漂移需求的重要性。结果发现，尽管出现了滑移现象，但光束仍具有屈服能力。但是，帧的响应是主观的，具体取决于输入运动的特征，尤其是频谱形状的波谷和波峰。