拆撑对高层悬挑转换桁架结构内力的影响
|
摘要
高层悬挑转换桁架结构因受力特殊,施工阶段通常需在悬挑端设置临时支撑,而临时支撑在最终拆除时结构会发生内力重分布。以珠海横琴保利国际广场二期工程为例,介绍其拆撑施工技术,根据施工实际状态建立有限元分析模型,对拆撑过程进行了数值模拟,并与施工监测数据进行了对比。结果表明:拆撑过程中,桁架层悬挑端的实测竖向变形规律与模拟结果相符,实测数据均小于理论值,且最大值不超过3 mm,由此反映出悬挑转换桁架结构刚度较大,且拆撑过程安全可控。在此基础上,对悬挑结构的临时支撑拆撑敏感性进行了分析,包括:支撑反力的敏感性和支撑点位置的敏感性,得出:拆撑过程中某一支撑点失效后,邻近支撑的支撑反力会发生较大变化,尤其是反力较大和位于角部的支撑的敏感性较高。因此拆撑过程中应采取有效措施确保拆撑施工的安全。
The high-rise cantilevered structure with transfer-truss needs to set the temporary supports on cantilevered sides during construction process because of the complexity of loads,and redistribution happens during the removing temporary support process. Taking the second phase project of Hengqin Poly International Square in Zhuhai as an example,the removing temporary support construction technique was introduced. The finite element analysis model was established according to the condition of the construction site,and the removing temporary support process was numerically simulated. Compared with the monitoring results,it showed that the monitoring vertical displacements,which were less than the theoretical values and no more than 3 mm,was consistent with the simulation results.Therefore,the stiffness of cantilevered structure with transfer-truss was large enough as well as the removing temporary support process was safe and controllable. Based on this,the removing sensitivity of the support reaction and position were analyzed. It showed that after the failure of one support in the removing process,the support reactions of the closer supports changed greatly,especially the supports with bigger reaction force or located at the corner had higher sensitivity. Therefore,effective measures should be taken to ensure construction safety in the removing temporary support process.
The high-rise cantilevered structure with transfer-truss needs to set the temporary supports on cantilevered sides during construction process because of the complexity of loads,and redistribution happens during the removing temporary support process. Taking the second phase project of Hengqin Poly International Square in Zhuhai as an example,the removing temporary support construction technique was introduced. The finite element analysis model was established according to the condition of the construction site,and the removing temporary support process was numerically simulated. Compared with the monitoring results,it showed that the monitoring vertical displacements,which were less than the theoretical values and no more than 3 mm,was consistent with the simulation results.Therefore,the stiffness of cantilevered structure with transfer-truss was large enough as well as the removing temporary support process was safe and controllable. Based on this,the removing sensitivity of the support reaction and position were analyzed. It showed that after the failure of one support in the removing process,the support reactions of the closer supports changed greatly,especially the supports with bigger reaction force or located at the corner had higher sensitivity. Therefore,effective measures should be taken to ensure construction safety in the removing temporary support process.
引文
[1]李惠,周峰,朱焰煌,等.国家游泳中心钢结构施工卸载过程及运营期间应变健康监测及计算模拟分析[J].土木工程学报,2012(3):1-9.
[2]蒋金生,叶可明.上海新国际博览中心钢桁架结构的施工及临时支承拆除的卸载过程分析[J].建筑结构学报,2006,27(5):118-122.
[3]何伟,何容,李晓克.洛阳天堂塔转换钢桁架临时支撑卸载有限元模拟与施工设计[J].施工技术,2014(8):65-69.
[4]石开荣,吕俊锋,姜正荣,等.高层悬挂结构卸载分析与监测[J].华南理工大学学报(自然科学版),2017(8):110-119.
[5]XIE W,REN L.Simulation Calculation over Removing Process of Temporary Supports for Large-Span Cantilever Steel Structure[C]∥Civil Engineering and Urban Planning 2012.Yantai:ASCE,2014:568-572.
[6]北京迈达斯技术有限公司.MIDAS Gen工程应用指南[M].北京:中国建筑工业出版社,2012.
[2]蒋金生,叶可明.上海新国际博览中心钢桁架结构的施工及临时支承拆除的卸载过程分析[J].建筑结构学报,2006,27(5):118-122.
[3]何伟,何容,李晓克.洛阳天堂塔转换钢桁架临时支撑卸载有限元模拟与施工设计[J].施工技术,2014(8):65-69.
[4]石开荣,吕俊锋,姜正荣,等.高层悬挂结构卸载分析与监测[J].华南理工大学学报(自然科学版),2017(8):110-119.
[5]XIE W,REN L.Simulation Calculation over Removing Process of Temporary Supports for Large-Span Cantilever Steel Structure[C]∥Civil Engineering and Urban Planning 2012.Yantai:ASCE,2014:568-572.
[6]北京迈达斯技术有限公司.MIDAS Gen工程应用指南[M].北京:中国建筑工业出版社,2012.