The purpose of this study is to evaluate the structural behavior of concrete‐filled steel tube (CFT) column to H‐beam connections with vertical through‐plate through full‐scale experiments and examine retrofit methods using the finite element method to improve the connection performance. For this purpose, monotonic loading tests were performed on three full‐scale specimens with varying thickness of vertical through‐plate. The experiments showed that the specimens suffer from a brittle failure due to the stress concentrations and residual stresses at the welds before the beams reach their plastic moment capacity. A series of sectional analyses were conducted to evaluate the effects of the thermally induced residual stresses due to welding and then the strain concentrations in the welded connection were estimated by comparing the experimental maximum strain and the analytical mean strain values. Based on these results, a retrofit model for reinforcing a stiff plate on the upper flange of the beam was proposed and analyzed to reduce the stress concentrations in the welded connection. The results showed that using the proposed retrofit approach, the stress concentration at the connection between the vertical through‐plate and the top flange is reduced by 72%, and the strength of the connection is increased by 70%, which is 10% higher than the analytical plastic moment capacity of the beam.

中文翻译：

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钢管混凝土柱与H型钢连接的垂直通孔的实验和数值研究

这项研究的目的是通过全尺寸实验评估钢管混凝土（CFT）柱与带有垂直通孔的H型钢连接的结构性能，并研究使用有限元方法进行改造的方法，以改善连接性能。为此，对三个全尺寸试样（具有不同的垂直通孔厚度）进行了单调加载测试。实验表明，由于在梁达到塑性矩承载力之前，焊缝处的应力集中和残余应力而使试样遭受脆性破坏。进行了一系列的截面分析，以评估由于焊接引起的热诱导残余应力的影响，然后通过比较实验最大应变和分析平均应变值来估算焊接连接中的应变浓度。基于这些结果，提出了一种加固梁上凸缘上的刚性板的改造模型，并进行了分析，以减少焊接连接中的应力集中。结果表明，使用建议的改造方法，垂直通孔板和顶部法兰之间的连接处的应力集中降低了72％，连接强度提高了70％，比原来的高出10％梁的分析塑性弯矩能力。提出了一种加固梁上凸缘上的刚性板的改造模型，并进行了分析，以减少焊接连接中的应力集中。结果表明，使用建议的改造方法，垂直通孔板和顶部法兰之间的连接处的应力集中降低了72％，连接强度提高了70％，比原来的高出10％梁的分析塑性弯矩能力。提出了一种加固梁上凸缘上的刚性板的改造模型，并进行了分析，以减少焊接连接中的应力集中。结果表明，使用建议的改造方法，垂直通孔板和顶部法兰之间的连接处的应力集中降低了72％，连接强度提高了70％，比原来的高出10％梁的分析塑性弯矩能力。