一种栓筋连接的装配式RC框架结构抗倒塌分析

为研究一种外包钢管栓筋连接的装配式钢筋混凝土框架结构的抗倒塌性能,完成了3根足尺装配式整体式长柱试验。首先使用有限元软件SAP2000中的多段线性塑性连结单元提出了一种简化的装配式柱模型,模拟出了该柱-柱节点,并与试验结果比较。然后采用抽柱法对一栋6层外包钢管栓筋连接的装配式框架结构和现浇框架结构进行连续倒塌分析,分别抽除首层角柱、首层长边中柱、首层短边中柱、首层内柱四种工况,得到了抽柱后的关键构件内力、位移时程曲线;最后通过Pushdown曲线分析装配与现浇结构的倒塌机制。研究结果表明:多段线性塑性连接单元较好地模拟了装配式柱-柱节点,模拟值与试验值比较吻合;在设计荷载作用下,四种工况中内柱的破坏对装配结构影响最大,其位移比现浇结构大了72.2%;在抗力曲线中发现,角柱破坏时是装配结构梁机制的承载力最低的情况,比现浇结构小了25.4%,内柱破坏时是装配结构悬链线机制的承载力最低的情况,比现浇结构小了33.1%。最终得出需要加强装配结构的内柱和边柱及其相邻梁构件的截面尺寸和配筋,以及外包钢管的厚度来提高其刚度,本文可为此类装配式结构的后续工程应用提供一种抗倒塌设计参考。

Analysis of collapse resistance of prefabricated RC frame structure with reinforcement connection

To study the progressive collapse of a prefabricated reinforced concrete frame structure (PRCS) with steel tube bolted connection, three full-scale prefabricated long columns were tested. First, a simplified prefabricated column model was proposed by using the multi-stage linear plastic connection element in SAP2000. The column-column joint was simulated and compared with test results. Then, a six-story PRCS connected by steel tube bolted bars and a six-story cast-in-place reinforced concrete frame structure (CRCS) were analyzed by removing column method. Four working conditions were removed, namely, the corner column, the long side middle column, the short side middle column, and the inner column of the first floor. The internal force and displacement time history curve of key components were obtained after removing the columns. Lastly, the collapse mechanisms of PRCS and CRCS were analyzed through Pushdown curves. Results show that the multi-stage linear plastic connection element well simulated the prefabricated column-column joint, and the simulation value was consistent with the test value. Under design load, the failure of the inner column had the greatest impact on the PRCS, and its displacement was 72.2% larger than that of the CRCS. By analyzing the Pushdown curves, it was found that when the corner column was damaged, the bearing capacity of the PRCS under beam mechanism was the lowest, which was 25.4% less than that of CRCS, and the lowest bearing capacity was 33.1% less than that of CRCS when the inner column was damaged. Finally, the section size and reinforcement of the inner and side columns and their adjacent beam members that are needed to be strengthened, as well as the thickness of the outer steel tube, were obtained to improve their rigidity. Therefore, this paper can provide reference for the collapse resistance design of the subsequent engineering application of such prefabricated structures.