Abstract Retrofitting timber columns in traditional timber structures with a steel jacketed splice joint has advantages of aesthetic appearance and similar mechanic performance to the intact columns as compared to conventional simple splice columns. The axial compression behavior of such retrofitted splice columns has been studied experimentally in detail. However, there is still a lack of a calculation model for their axial compressive strength and general guideline for their design. The objective of this study is to establish a theoretical calculation model for this type of retrofitted splice columns. Firstly, a theoretical model for the axial compressive strength of splice columns retrofitted with a steel jacket is proposed considering the contact stresses at a splice joint and the relevant stability theory. Secondly, the buckling modes of splice columns and the actual stress distributions at the splice joints (i.e. the compressive stresses at the steel-timber and timber-timber interfaces) are thoroughly investigated. Finally, the theoretical model is validated by the experimental data and finite element analysis results with different splice parameters. Comparisons show that the theoretical calculations in terms of the bearing capacity and stability coefficient agree well with the experimental results. The proposed theoretical model is also shown to be suitable for predicting the axial compressive strength of a retrofitted splice column with the location of the splice from the column end ranging from 1/5 to 1/2 of the column length. The relative errors in the theoretical bearing capacities with respect to the finite element results are found to be less than that using the stability coefficient. From the analysis results, the length of the splice and the total length of the steel jacket are recommended to be in the range of 0.5~1.5 and 2~4.5 times of the column diameter, respectively. This proposed theoretical model can be applied in the retrofitting design of timber columns in historical timber structures, and it can also be applied in the development of new large-space timber structures where splice columns may be incorporated.

中文翻译：

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拼接改造细长木柱承载力的分析模型

摘要 在传统木结构中采用钢夹套拼接接头改造木柱，与传统的简单拼接柱相比，具有外观美观和与完整柱相似的力学性能的优点。已经通过实验详细研究了这种改造后的拼接柱的轴向压缩行为。然而，仍然缺乏其轴向抗压强度的计算模型和其设计的一般指南。本研究的目的是建立该类型改装拼接柱的理论计算模型。首先，考虑了拼接接头处的接触应力和相关的稳定性理论，提出了带钢护套改造的拼接柱轴向抗压强度的理论模型。第二，对拼接柱的屈曲模式和拼接接头处的实际应力分布（即钢-木材和木材-木材界面处的压应力）进行了彻底研究。最后，通过实验数据和不同拼接参数的有限元分析结果对理论模型进行了验证。比较表明，理论计算的承载力和稳定系数与试验结果吻合较好。所提出的理论模型也被证明适用于预测改装拼接柱的轴向抗压强度，其中拼接柱末端的拼接位置范围为柱长的 1/5 到 1/2。发现理论承载力相对于有限元结果的相对误差小于使用稳定性系数的误差。从分析结果来看，接头长度和钢套总长度建议分别在柱径的0.5~1.5倍和2~4.5倍范围内。该理论模型可应用于历史木结构中木柱的改造设计，也可应用于可采用拼接柱的新型大空间木结构的开发。