圆钢管再生混凝土轴压短柱对比试验研究

Comparative experimental research on recycled aggregate concrete filled steel tubular columns subjected to axial compression

对不同截面形式和不同混凝土类型的6根圆钢管混凝土试件进行试验研究,并对其轴力-纵向应变全过程进行模拟,其中截面形式有圆实心、圆套圆中空夹层、圆套方中空夹层3种,混凝土类型包括普通混凝土和再生混凝土(再生粗骨料取代率为50%)两类。结果表明:截面形式对圆钢管再生混凝土试件的弹性模量、轴压强度和后期延性有一定影响;在达到极限承载力之前,两种混凝土类型的圆钢管混凝土试件的轴压刚度及外钢管的横向应变发展规律基本相同;在达到极限承载力之后,圆钢管再生混凝土试件的延性和后期承载能力均不如相应的圆钢管普通混凝土试件;有限元计算得到的试件的极限承载力和前期刚度与试验结果吻合较好。

A comparative experimental research was conducted to investigate the mechanical properties of 6 concrete filled steel tubular（ CFST） columns with different types of cross sections and concrete types under axial compression. The whole process of axial force-longitudinal strain was simulated. The section types include CFST with circular section,concrete filled double-skin steel tube（ CFDST） with circular hollow section（ CHS） as both inner and outer tubes and CFDST with square hollow section（ SHS） as the inner tube and CHS as the outer tube. Two types of concrete were normal concrete and recycled aggregate concrete,and the replacement ratio of recycled coarse aggregates was 50%. The research results show that the section type has some effect on elastic modulus,axial compressive strength and ductility of recycled aggregate concrete filled steel tubular（ RACFST） columns. Before the load reaches the ultimate load,the axial stiffness and the regulation of development of lateral strain of outer tubes of CFST and RACFST are roughly similar. After the load reaches the ultimate load,the ductility and the bearing capacity of RACFST are not as good as those of CFST columns with the same section type. The bearing capacity and axial stiffness in the early stage calculated by the finite element method were in good agreement with those measured by test. The calculated results and test results were verification to each other.