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通过15根薄壁方钢管再生混合柱在定常轴力和水平往复荷载作用下的拟静力试验,研究了废弃混凝土取代率、钢管壁厚、轴压比等参数对试件抗震性能的影响。基于新、旧混凝土的组合强度,根据国内外钢管混凝土结构的设计标准以及基于ABAQUS的纤维梁单元模型,对试件的水平承载力进行了计算分析。研究表明:废弃混凝土取代率在0～40%之间变化对试件的初始抗侧刚度、钢管局部屈曲、破坏位移、负刚度段行为、等效黏滞阻尼系数、滞回曲线形状影响有限,但再生混合柱的水平承载力总体上比全现浇柱有所降低;当钢管壁厚在1.78～5.50 mm之间变化时,随钢管壁厚增加试件并未表现出更好的变形能力;在钢管壁厚仅1.78 mm(宽厚比168.5)的情况下,轴压比0.4的再生混合柱的破坏位移角可达1/35,满足我国现行抗震规范的层间位移角限值要求;采用5部现行标准计算薄壁方钢管再生混合柱的水平承载力可获得与同条件全现浇柱相当的安全性;横截面积和用钢量相同时,薄壁方钢管再生混合柱的抗震性能优于钢筋混凝土柱。研究发现,薄壁方钢管再生混合柱应用于中、低轴压比(实际轴压比小于0.4)的情况是可行的。
Quasi-static tests of 15 thin-walled square steel tube hybrid columns under constant axial force and horizontal reciprocating load are carried out to study the influence of the parameters such as the replacement ratio of waste concrete, the wall thickness of steel pipe and the axial compression ratio on the seismic performance of the specimens. Based on the combined strength of new and old concrete, the horizontal bearing capacity of the specimens was calculated and analyzed according to the design standards of CFST structures at home and abroad and the fiber beam element model based on ABAQUS. The results show that the effect of the replacement ratio of waste concrete between 0% ~ 40% on the initial lateral stiffness, local buckling, failure displacement, negative stiffness section, equivalent viscous damping coefficient and shape of hysteresis curve is limited, However, the horizontal bearing capacity of the regenerated hybrid column is generally lower than that of the full cast-in-situ column. When the wall thickness varies from 1.78 to 5.50 mm, the specimen does not show better deformability with the increase of wall thickness. When the wall thickness of steel pipe is only 1.78 mm (width to thickness ratio of 168.5), the failure displacement angle of regenerative mixing column with axial compression ratio of 0.4 can reach 1/35, which meets the requirements of the limit of interlayer displacement of the current seismic code in our country. The current standard calculation of the horizontal bearing capacity of the thin-walled square steel tube mixed column can obtain the same safety as that of the cast-in-situ concrete column under the same condition. The seismic performance of the thin-walled square steel tube mixed column is better than that of the reinforced concrete column . The results show that it is feasible to apply the thin-walled square steel tube hybrid column to middle and low axial compression ratio (the actual axial compression ratio is less than 0.4).