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大型张拉膜结构更新改造施工关键技术

Research on Key Technologies for Large-scale Tensioned Membrane Replacement Construction

  • 摘要: 随着城市建筑更新需求日益增长,张拉膜结构因材料老化导致的更换工程成为行业难题。亟需建立一套无损、安全、绿色的快速更换技术体系。本研究针对大型张拉膜无损更换技术瓶颈,对钢结构采用“2+2+4”翻新工艺,即两次脱漆、两次打磨、四层涂装。高空作业施工过程使用8 mm钢丝绳生命线安全系统与17道防护网及混合升降式高空作业车组成的三维防护体系,确保施工过程安全。采用汽车吊分级牵引的无损拆膜技术,以25 t汽车吊(主臂18.7 m)分级牵引,针对最不利工况,即吊装重物、配重与吊车两个支腿成一条直线,吊装重物最大重量为2.8 t,吊装半径16 m,通过力学模型分解支腿荷载(Nmax=13.76 t),核算地基承载力(22 kPa),验证其小于混凝土路面及路基设计承载力(700 kPa、200 kPa),确保吊装安全。按钢帽→边缘桅杆(25 t汽车吊临时牵引)→膜材→中间桅杆→骨架的顺序拆除,避免结构损伤。在广州海洋馆2340 m2膜结构更换工程实践中,实现83 d高效施工(较传统工艺缩短41%),骨架材料回收率100%(钢结构全复用),废旧膜材回收率达85%,综合成本节约23%。符合绿色施工要求,验证了该技术体系在保障高空作业安全、维持结构力学平衡及提升施工质量等方面的显著成效,为类似工程提供了重要参考。

     

    Abstract: With the increasing demand for urban architectural renewal, the replacement projects of tensioned membrane structures due to material aging have become a tough challenge in the industry. There is an urgent need to establish a non-destructive, safe and green technical system for rapid replacement. This study targets the technical bottleneck in the non-destructive replacement of large-scale tensioned membranes and applies a “2+2+4” refurbishment process to the steel structure—namely, two stages of paint removal, two stages of grinding, and four layers of coating. During high-altitude operations, a three-dimensional protection system composed of an 8mm steel wire rope lifeline safety system, 17 protective nets, and hybrid lifting aerial work vehicles is utilized to ensure construction safety. An innovative non-destructive membrane removal technology with graded traction by mobile cranes is employed, which adopts a 25 tons mobile crane (18.7 m main boom) for graded traction. For the most unfavorable working condition where the hoisted load, counterweight, and two outriggers of the crane are in a straight line – involving a maximum hoisted load of 2.8 tons with a lifting radius of 16 meters – the outrigger load is decomposed through mechanical modeling (Nmax=13.76 tons), and the foundation bearing capacity is calculated (22 kPa). It is verified that this bearing capacity is less than the design bearing capacity of the concrete pavement and subgrade (700 kPa, 200 kPa), so as to ensure lifting safety. The dismantling is carried out in the sequence of steel cap → edge mast (temporarily pulled by 25 tons mobile cranes) → membrane material → middle mast → framework to avoid structural damage.In the practical application of the 2340 m2 membrane structure replacement project at the Guangzhou Oceanarium, efficient construction was completed in 83 days (41% shorter than traditional processes), with a 100% recovery rate of skeleton materials (full reuse of steel structures) and an 85% recovery rate of waste membrane materials, achieving a 23% reduction in comprehensive costs. It meets the requirements of green construction, verifying the significant effectiveness of this technical system in ensuring high-altitude operation safety, maintaining structural mechanical balance, and improving construction quality, thus providing important references for similar projects.

     

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