Peng Jun, Wang Dan-Dan, Kang Shao-Bo, Zhou Shu-Rong
Department of Civil Engineering, Chongqing Vocational Institute of Engineering, Chongqing 402260, China.
School of Civil Engineering, Chongqing University, Chongqing 400045, China.
Materials (Basel). 2023 Jul 31;16(15):5370. doi: 10.3390/ma16155370.
The bond between a steel reinforcement/rod and glulam plays a crucial role in the resistance and deformation capacity of timbers joints. Existing studies provide different bond-slip models for reinforcements and rods with different anchorage lengths, in which the relationship between local bond stress and global bond behaviour cannot not be established. This study presents a unified analytical method for predicting the bond-slip behaviour of ribbed bars and threaded rods along the grain using a local bond-slip model of reinforcement at the elastic and post-yield stages. In the analytical method, equilibrium, compatibility, and constitutive models for reinforcement and rods are considered. The method is verified using test data of rebars and rods with different anchorage lengths. Comparisons between the experimental and calculated results suggest that the analytical method yields reasonably good predictions of the load-slip relationship and failure mode. Furthermore, the embedment lengths required for yield and the ultimate strengths of the reinforcement and rods along the grain are determined by assuming uniform bond stress distributions over the elastic and post-yield steel segment. The average bond stress over the entire anchorage length is calculated and compared with existing equations. Design recommendations for anchorage lengths are proposed for ribbed bars and threaded rods glued in glulam.
钢筋/杆与胶合木之间的粘结在木材节点的抗力和变形能力中起着关键作用。现有研究针对不同锚固长度的钢筋和杆提供了不同的粘结-滑移模型，但其中局部粘结应力与整体粘结行为之间的关系尚未建立。本研究提出了一种统一的分析方法，利用钢筋在弹性和屈服后阶段的局部粘结-滑移模型来预测带肋钢筋和螺纹杆沿木纹方向的粘结-滑移行为。在该分析方法中，考虑了钢筋和杆的平衡、协调和本构模型。利用不同锚固长度的钢筋和杆的试验数据对该方法进行了验证。试验结果与计算结果的比较表明，该分析方法能对荷载-滑移关系和破坏模式给出较为合理的预测。此外，通过假定弹性和屈服后钢材段上粘结应力分布均匀，确定了沿木纹方向钢筋和杆屈服所需的埋入长度以及极限强度。计算了整个锚固长度上的平均粘结应力，并与现有公式进行了比较。针对胶合在胶合木中的带肋钢筋和螺纹杆，提出了锚固长度的设计建议。
