摘要:
摘 要：双钢板-混凝土组合墙（SCS墙）已在超高层建筑、核电站等重要工程中得到应用，其在全生命周期内遭受偶然、极端荷载作用下的性能值得关注。鉴于火灾与爆炸通常同时发生，而高温会显著降低钢材和混凝土的力学性能，从而导致结构构件的抗爆性能严重退化。为此，本文采用ABAQUS有限元软件建立了120个火灾-爆炸耦合作用下SCS墙分析模型。首先，基于已有的火灾下耐火极限试验和常温下爆炸试验对有限元模型进行验证；其次，分析了火灾-爆炸耦合作用下SCS墙工作机理，重点研究了受火时间、爆炸当量、含钢率、材料强度、钢筋连接间距与轴压比对抗爆性能的影响规律；最后基于等效单自由度模型提出了火灾-爆炸耦合作用下SCS墙跨中最大挠度的预测公式。研究结果表明：SCS墙在火灾与爆炸耦合作用下主要表现为整体受弯破坏；随着受火时间增加，受火面钢板耗能占比降低，背火面钢板的塑性变形逐渐成为墙体的主要耗能机制；受火时间、爆炸当量与钢材强度对火灾下SCS墙抗爆性能影响明显，而混凝土强度影响较小；基于等效单自由度模型提出的计算公式可较好预测火灾与爆炸耦合作用下SCS墙的跨中最大挠度。
Abstract:
Abstract: Steel-concrete-steel composite walls (SCS walls) have been applied in high-rise buildings and nuclear power plants. Its performance under accidental and extreme loads during the whole life cycle deserves attention. Considering that fires and explosions often occur simultaneously, and that the mechanical properties of steel and concrete significantly deteriorate at high temperatures, leading to serious degradation of blast resistance of structural members. In this context, a total of 120 finite element (FE) models of SCS walls under combined fire and explosion were established using ABAQUS software. First, the FE models were verified based on existing fire resistance tests and explosion tests at room temperature on SCS walls. Then, the blast resistance mechanism of SCS walls was analyzed, and the influences of key parameters, including fire duration, explosion charge, steel plate ratio, material strength, tie bars spacing and axial compression ratio on the explosion resistance were investigated. Finally, based on the single-degree of freedom method, the formulas were proposed to predict the maximum deformation of SCS walls under combined fire exposure and explosion. The results show that SCS walls primarily exhibit overall bending failure under coupled fire exposure and explosion. With the increase of fire duration, the energy dissipation contribution of the steel plate on the fire-exposed side decreases, and the plastic deformation of the steel plate on the non-fire-exposed side gradually becomes the main energy dissipation component. Fire duration, explosion charge and steel strength significantly affect the blast resistance of SCS walls under fire conditions. When exposed to fire for 90 minutes, the maximum mid-span deformation decreases by approximately 22%, as the steel yield strength increases from 235MPa to 460MPa. However, the influence of the concrete strength is minor. The maximum deformation of SCS walls can be reasonably predicted by the proposed formulas based on the single-degree of freedom method under coupled fire exposure and explosion.
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