薄壁方形钢管再生块体混合短柱破坏形态分析

Analysis on failure modes of thin-walled square steel stub columns filled with demolished concrete lump

为揭示方形钢管再生块体混合构件的受力性能及破坏机理,对薄壁方形钢管再生块体混合短柱的荷载-变形曲线进行全过程分析;并以轴压破坏形态为切入点,从钢管宽厚比、核心混凝土强度、加劲肋等套箍系数因素对试件破坏形态的影响进行了分析。研究结果表明:在破坏阶段不带肋试件呈软化特性,带肋试件呈加劲特性;薄壁方形钢管再生块体混合短柱的主要破坏形态为试件中部腰鼓形压皱破坏,核心组合混凝土试件中再生块体先在块体卵石与旧混凝土界面产生裂缝,随后卵石被压碎而发生破坏;随套箍系数的增大,钢管对核心混凝土约束作用增强,则趋于腰鼓形破坏,反之发生剪切形破坏。通过研究建立薄壁方形钢管再生块体混合短柱的破坏模型。

In order to reveal the mechanical property and failure mechanism of square steel stub columns filled with demolished concrete lump, analysis the whole process of load-deformation curves of thin-walled square steel stub columns filled with demolished concrete lump, and to axial compression failure modes as the entry points, the influence of failure modes of specimens are analyzed from the steel tube width-thickness, the core strength of concrete, stiffener and other hoop coefficient factors.The research results show that during in destruction no ribbed stiffener specimens show softening behavior and ribbed stiffener specimens show strengthen phenomenon; The main failure modes of thin-walled square steel stub columns filled with demolished concrete lump is that middle of the specimen is drum-type crushed damage, in the core combination of concrete recycled concrete Lump is first occurred cracks and in the interface of lump pebbles and old concrete,then pebbles are crushed and produce damage;With the increasing of the hoop coefficient, the constraint of steel tube is enhanced for core concrete, the specimens are tend to be drum-type damage, on the contrary, tend to occur shear-shaped damage.Through this study is to establish the failure model of thin-walled square steel stub columns filled with demolished concrete lump.