钢支撑加固RC框架抗连续倒塌试验与数值模拟研究

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振动与冲击 ›› 2022, Vol. 41 ›› Issue (5) : 173-181.

论文

翁运昊1,李治2,邓小芳1,钱凯1,2

作者信息 +

Tests and numerical simulation for anti-progressive collapse of RC frame reinforced with steel braces

WENG Yunhao1, LI Zhi2, DENG Xiaofang1, QIAN Kai1,2

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文章历史 +

摘要

为研究钢支撑对RC框架抗连续倒塌性能的加固效应，在实验室制作了2榀RC平面子框架试件，并对其中1榀框架通过钢支撑进行加固，采用pushdown加载方式研究钢支撑对RC框架破坏模式和抗倒塌承载能力的影响。试验结果表明：钢支撑可以提高峰值荷载超过122 %，其承载能力随拉杆的断裂而突然下降；由于压杆在加载初期就发生严重的平面外屈曲破坏，故仅对试件的初始刚度有影响，对峰值荷载作用很小。为进一步量化拉杆与压杆的加固贡献，通过商用有限元软件LS-DYNA进行精细有限元分析。有限元结果进一步验证了试验结果：采用角钢加固RC框架，压杆在加载初期容易发生平面外屈曲，对结构抗力影响不大，抗力提升主要由拉杆提供；通过拓展分析发现：采用防屈曲支撑加固可以显著提升压杆对结构抗力贡献，如压杆使用方钢管混凝土截面比L形截面峰值荷载提升超过42.8%。

Abstract

To study the strengthening effects of steel bracing on progressive collapse resistance of RC frames, two planar RC beam-column sub-frames were tested in laboratory. One of the specimens is strengthened by steel braces. Pushdown loading method is used to study the effects on failure mode and load resisting capacity. Experimental results indicated that steel brace can upgrade the first peak load by 122 %. The decrement of load resisting capacity is due to fracture of the tensile braces. The out-of-plane buckling of the compressive brace become very severe in the beginning stage. Therefore, it only affects the initial stiffness of the specimen and little effects on load resisting capacity of the specimen. Then, Commercial finite element (FE) software LS-DYNA is utilized to further quantify the strengthening contribution from the tensile and compressive braces. The FE model confirmed the experimental results that the compressive brace made by angle steel will become severe buckling in the beginning stage and thus, it has little effect on the structural resistance and the load resistance mainly attributed into the tensile braces; Buckling-restrained brace could significantly increase the contribution of the compressive brace for load resistance; If concrete infilled square section replaces the L-shaped section, the load resisting capacity could increase by 42 %.

导出引用

翁运昊1,李治2,邓小芳1,钱凯1,2 . 钢支撑加固RC框架抗连续倒塌试验与数值模拟研究[J]. 振动与冲击, 2022, 41(5): 173-181

WENG Yunhao1, LI Zhi2, DENG Xiaofang1, QIAN Kai1,2. Tests and numerical simulation for anti-progressive collapse of RC frame reinforced with steel braces[J]. Journal of Vibration and Shock, 2022, 41(5): 173-181

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