自密实自应力矩形钢管混凝土柱抗震性能试验研究

为研究不同长宽比对自密实自应力矩形钢管混凝土柱抗震性能的影响,本试验制作三根不同长宽比的试件,并分别从试件的荷载-位移滞回曲线、骨架曲线、延性、耗能及刚度退化来综合分析自密实自应力矩形钢管混凝土柱的抗震性能.研究结果表明:角部焊缝过早的撕裂是导致试件承载力急剧下降的根本原因,因此在今后工程应用中,应特别重视对角焊缝质量的保证;随着试件长宽比的增加,滞回曲线的饱满程度有所减小,说明试件长宽比越大,在试验过程中越容易受剪力或滑移的影响;随着试件长宽比的增加,最大水平承载力提高,其中试件ZJGC-2较ZJGC-1提高约7%,ZJGC-3较ZJGC-1提高了近17%,极限位移则有所减小,长宽比越大,对应试件的骨架曲线后期下降段越明显;随着试件长宽比的增加,对应的位移延性、耗能能力均有下降的趋势,刚度退化越来越明显.由试件破坏形态可以发现,长宽比大的试件首先出现角焊缝撕裂现象,进而使试件承载力和刚度急剧降低,因此为保障自密实自应力矩形钢管混凝土柱的位移延性及抗震性能,需对结构的长宽比做出明确的规定.

Seismic Performance of Self-compacting Self-stressing Concrete-filled Rectangular Steel Tubular Column

In order to research the influence of different length-width ratio on seismic behavior of self-compacting self-stress rectangular steel tube concrete column,three specimens with different length-width ratio were fabricated in this experiment, and the seismic performance of self-compacting self-stress rectangular steel tube concrete column was analyzed respectively from the load displacement hysteresis curve,skeleton curve,ductility,energy dissipation and stiffness degradation.The result shows that the premature tearing of the fillet weld is the fundamental cause of the sharp decrease in the bearing capacity of the specimen,Therefore,in the future engineering applications,particular attention should be paid to the quality assurance of fillet welds.With the increase of the length-width ratio of specimens,the degree of fullness of the hysteretic curve decreases,which shows that there is some shear force or slip effects in the specimens with large aspect ratio during the test.With the increase of the length-width ratio of the specimen, the maximum horizontal bearing capacity is improved, in which the specimen ZJGC-2 is increased by about 7% compared with the ZJGC-1, the ZJGC-3 is increased by nearly 17%, the limit displacement is decreased,the larger the aspect ratio is, the more obvious the late fall of the skeleton curve of the corresponding specimen.With the increase of the length-width ratio of specimens,there is a downward trend in the displacement ductility and energy dissipation capacity of corresponding specimens, and the stiffness degradation is more and more obvious.It can be found from the specimen failure form that the specimen with large length-width ratio firstly appears the tear of the fillet weld, which makes a sharp decreases to the bearing capacity and stiffness of the specimen, therefore, in order to ensure that the self-compacting self-stress rectangular steel tube concrete column has enough deformation ability,it is necessary to define the length-width ratio of the section clearly.