Abstract This paper presents an experimental and numerical investigation on the bearing behavior of multi-bolt high strength steel connections in single bolt line. Three grades of high strength steel with nominal yield stress of 550 MPa, 690 MPa and 890 MPa were used to fabricate thirty lap connections with two or three bolts. It is found that the deformation capability of high strength steel plate near bolt hole is sufficient to meet the deformation demand of compatibility in multi-bolt connection even with an intended bolt hole misalignment of 2 mm for M24 high strength bolt. The comparison with Eurocode3 and AISC 360-16 is conducted. When no partial or safety factors are considered, the original formulae of Eurocode3 already has sufficient safety while AISC 360-16 gives unsafe predictions. Numerical models were established and verified by test results. With the obtained results, the full-range distribution of internal load among different bolts can be divided into four stages. Features for each stage are summarized and the effect of bolt hole misalignment on the distribution pattern is evaluated. Numerical analysis results indicate that, behavior of an individual bolt in multi-bolt connection may be influenced by surrounding bolts. The formation of critical yielding band between different bolts may explain this influence. Based on the experimental and numerical analyses, this paper proposed a new ultimate bearing resistance model for multi-bolt connections. The proposed model is capable of describing the nonlinearity in the ultimate bearing resistance of multi-bolt connection and achieves improved predicting accuracy compared to classical models.

中文翻译：

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多螺栓高强钢连接的承载性能

摘要 本文对单螺栓线中多螺栓高强度钢连接的承载性能进行了实验和数值研究。使用公称屈服应力为 550 MPa、690 MPa 和 890 MPa 的三个等级的高强度钢，用两个或三个螺栓制造三十个搭接连接。研究发现，即使M24高强螺栓预期螺栓孔错位2mm，螺栓孔附近高强度钢板的变形能力也足以满足多螺栓连接兼容的变形需求。进行了与 Eurocode3 和 AISC 360-16 的比较。在不考虑部分或安全因素的情况下，Eurocode3 的原始公式已经具有足够的安全性，而 AISC 360-16 给出了不安全的预测。建立数值模型并通过试验结果进行验证。根据所得结果，可以将不同螺栓之间的内载荷全范围分布分为四个阶段。总结了每个阶段的特征，并评估了螺栓孔错位对分布模式的影响。数值分析结果表明，多螺栓连接中单个螺栓的行为可能会受到周围螺栓的影响。不同螺栓之间临界屈服带的形成可以解释这种影响。基于实验和数值分析，本文提出了一种新的多螺栓连接极限承载阻力模型。