Abstract The joints with glued-in steel rods are efficient joints in the design of timber structures, due to their high stiffness, strength and fire resistance. The ductile behaviour of joints can be achieved through designing the yielding of steel rods prior to wood failure. In practice, the joints are generally with multiple rods rather than single rod. In the case of multiple glued-in rods, the yielding of single rod is designed as prior failure by using mild steel rod, and the load-carrying capacity of joints is expected to be equal to the yield capacity of single rod multiplied by the number of rods. However, the actual pull-out capacity of single rod in timber joints with multiple glued-in rods can be less than that in timber joints with a single glued-in rod, due to the group effect of glued-in rods. Thus, the brittle failure of pull-out of rods can still occur prior to the yielding of steel rods in timber joints with multiple glued-in rods, though the yielding of single rod is designed as prior failure. The pull-out capacity of multiple rods can generally be considered as the pull-out capacity of single rod multiplied by the effective number of rods instead of the actual number of rods. Therefore, it is necessary to determine the effective number of rods in the case of pull-out of rod. This paper presented an experimental investigation on joints composed of multiple glued-in steel rods (two and four rods with different rod spacing) in glued-laminated timber with the pull-out failure mode. The actual experimental results combined with those from literatures, were used to analyze the influence of main factors, e.g. rod diameter, slenderness ratio of rods, number of rods and rod spacing to diameter, on the effective number of rods. Afterwards, based on these main factors, an empirical expression of the effective number of rods was derived. Finally, a model of load-carrying capacity for timber joints with multiple glued-in rods was proposed. The load-carrying capacity of timber joints with multiple rods should be calculated as the minimal value between yielding capacity of a single rod multiplied by the number of rods and pull-out capacity of a single rod multiplied by the effective number of rods. The proposed model is capable of predicting the failure mode and load-carrying capacity for multiple rods.

中文翻译：

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多根胶合钢棒平行于纹理加载的木材接头的承载能力

摘要 粘钢接头具有较高的刚度、强度和耐火性，是木结构设计中的有效接头。接头的延展性可以通过在木材破坏之前设计钢筋的屈服来实现。在实践中，接头通常是多杆而不是单杆。在多根胶合杆的情况下，采用低碳钢杆将单杆屈服设计为先失效，预计接头承载能力等于单杆屈服能力乘以数量杆。但是，由于胶条的群效应，多条胶合木节的单杆实际拉拔能力可能小于单条胶合木节的实际拉拔能力。因此，尽管单杆的屈服被设计为在先失效，但在多根胶合木杆的木材接头中，在钢杆屈服之前仍然会发生杆拔出的脆性破坏。多杆的拔出能力一般可以认为是单杆的拔出能力乘以有效杆数而不是实际杆数。因此，有必要在拉杆的情况下确定有效的杆数。本文对胶合层压木材中多根胶粘钢棒（两根和四根不同棒间距的棒）组成的接头进行了拉拔破坏模式的实验研究。结合实际试验结果，结合文献，分析了杆径、直径等主要因素的影响。杆的长细比、杆数和杆间距与直径、有效杆数有关。随后，基于这些主要因素，推导出有效杆数的经验表达式。最后，提出了多胶合杆木材接头的承载能力模型。多杆木材节点的承载能力应按单杆屈服能力乘以杆数与单杆抗拔能力乘以有效杆数之间的最小值计算。所提出的模型能够预测多杆的失效模式和承载能力。推导出有效杆数的经验表达式。最后，提出了多胶合杆木材接头的承载能力模型。多杆木材节点的承载能力应按单杆屈服能力乘以杆数与单杆抗拔能力乘以有效杆数之间的最小值计算。所提出的模型能够预测多杆的失效模式和承载能力。推导出有效杆数的经验表达式。最后，提出了多胶合杆木材接头的承载能力模型。多杆木材节点的承载能力应按单杆屈服能力乘以杆数与单杆抗拔能力乘以有效杆数之间的最小值计算。所提出的模型能够预测多杆的失效模式和承载能力。多杆木材节点的承载能力应按单杆屈服能力乘以杆数与单杆抗拔能力乘以有效杆数之间的最小值计算。所提出的模型能够预测多杆的失效模式和承载能力。多杆木材节点的承载能力应按单杆屈服能力乘以杆数与单杆抗拔能力乘以有效杆数之间的最小值计算。所提出的模型能够预测多杆的失效模式和承载能力。