钢管高强再生混凝土叠合柱轴压性能

Axial compression behavior of high-strength recycled concrete filled steel tubular composite columns

以混凝土种类、钢管截面形状和方钢管内是否设置十字形拉结筋为主要变化参数,完成了2个钢管高强普通混凝土叠合柱(CFSTRCC)和3个钢管高强再生CFSTRCC轴心受压试验,研究了钢管高强再生混凝土叠合柱与钢管高强普通混凝土叠合柱轴心受压性能差异。研究结果表明,钢管高强再生混凝土叠合柱损伤发展过程和破坏形态与钢管高强普通混凝土叠合柱相似,钢管高强再生混凝土叠合柱承载力较高,耗能能力较强,但外围钢筋混凝土剥落程度严重,延性较差。在方钢管内设置十字形拉结筋后,拉结筋增强了方钢管对核心混凝土的约束,延性得到显著改善,承载力和耗能亦提高显著,同时峰值荷载对应更大的峰值应变,材料利用更充分。在钢管截面积相等、材料强度接近的条件下,内置圆钢管的CFSTRCC与内置方钢管的CFSTRCC相比,具有更高的承载能力和耗能能力,表现出更好的延性。根据国内外相关规程对26个钢管再生CFSTRCC进行轴压承载力计算,结果表明CFSTRCC轴压承载力计算结果与实测结果吻合较好。

To study the difference of the axial compressive performance of recycled concrete composite columns and ordinary concrete composite columns,the experiments of two high-strength ordinary concrete-filled steel tube reinforced concrete columns(CFSTRCC)and three high-strength recycled CFSTRCC were conducted under axial loading.The concrete type,cross-sectional shape of the steel tube and whether the cross-shaped tie bars were set or not in the square steel tube were chosen to be the main parameters.The experimental results show that the damage development process and failure modes of recycled concrete specimens are similar to those of normal concrete specimens.The bearing capacity and energy dissipation capacity of recycled concrete specimens are higher than those of the ordinary concrete specimens.However,it has serious spalling of concrete and poor ductility.When the set cross-shaped tie bars were installed in the square steel tube,the ductility has been significantly improved,and the bearing capacity and energy consumption have also been significantly increased due to the tie bar enhancing the restraint of the square steel tube to the core concrete.Meanwhile,the peak load corresponds to a larger peak strain,so the materials are more fully utilized.Under the condition of the steel tube equal cross-sectional area and close material strength,CFSTRCC with circular steel tube has higher bearing capacity,better deformation ability and stronger energy dissipation capacity than CFSTRCC with square steel tube.According to the relevant domestic and foreign regulations,the ultimate bearing capacity of 26 recycled CFSTRCC from this paper and other references were calculated.The results show that the calculation results for the axial compression bearing capacity of CFSTRCC are in well agreement with the experiment results.