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提出外套方钢管自密实混凝土加固钢筋混凝土方形截面柱的复合加固方法。通过对8根加固柱试件(其中1根为增大截面法加固钢筋混凝土方形截面柱试件、7根为复合加固法加固钢筋混凝土方形截面柱试件)和2根未加固钢筋混凝土方形截面柱试件进行轴心受压试验,研究不同加固方法、钢管壁厚、后浇自密实混凝土强度和加载方式对加固柱力学性能的影响。结果表明:采用外套方钢管自密实混凝土复合加固法能显著提高原柱的承载力和延性;在用钢量基本相同的情况下,复合加固柱试件的承载力和延性均高于增大截面法加固柱试件;随着钢管壁厚的增大,复合加固柱试件的承载力和延性都显著增大;随着后浇混凝土强度的提高,复合加固柱试件的承载力有所增大,但延性显著下降;采用钢管与混凝土全截面受压加载方式的复合加固柱试件的延性和承载力略小于仅混凝土受压加载方式和上端仅混凝土受压、下端全截面受压加载方式的复合加固柱试件。在试验研究的基础上,建立了外套方钢管自密实混凝土复合加固钢筋混凝土方形截面短柱轴压承载力计算式,计算结果与试验结果吻合良好。
The composite reinforced method of reinforced concrete square section columns with self-compacting concrete filled steel tubes is proposed. Eight reinforced columns (one of them is a square column specimen reinforced by reinforced concrete with an enlarged section method, and seven square column specimens reinforced by a composite reinforcement method) and two square sections of unreinforced reinforced concrete The axial compression tests were carried out on the column specimens to study the effects of different reinforcement methods, the wall thickness of steel pipe, the strength of post-poured self-compacting concrete and the loading method on the mechanical properties of reinforced columns. The results show that the bearing capacity and ductility of the self-compacting concrete-filled square steel tube can significantly increase the bearing capacity and ductility of the original column. When the amount of steel is basically the same, the bearing capacity and ductility of the composite reinforced column specimens are higher than those of the enlarged section With the increase of steel pipe wall thickness, the bearing capacity and ductility of the composite reinforced column specimens increased significantly. With the increase of the strength of post-cast concrete, the bearing capacity of the composite reinforced column specimens increased But the ductility decreased significantly. The ductility and bearing capacity of the composite reinforced columns subjected to full load of steel tube and concrete were slightly less than that of the concrete-only compressive loading and compression of the upper concrete only, Of composite reinforcement column specimens. On the basis of the experimental study, the calculation formula of the axial bearing capacity of reinforced concrete square column with self-compacting concrete filled steel tube is established. The calculated results are in good agreement with the experimental results.