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对2个足尺钢筋混凝土平板无梁楼盖试件进行了抗火试验,测量了火灾作用下板的平面内(水平)位移和平面外(竖向)位移等,考察了板的约束反力变化,分析了混凝土板沿厚度的温度分布以及钢筋的温度变化。结果表明:单面受火的钢筋混凝土板沿厚度的温度呈非线性分布,温度梯度随时间的增长而快速增大,并且毛细孔水和凝胶水等水分的存在使混凝土在100℃时产生了升温水平段;水分不仅影响了混凝土的升温,还使受火混凝土产生爆裂,含水率太高时板将因混凝土的爆裂而导致破坏;柱上板带和跨中板带的约束反力均产生了显著变化,柱上板带的约束反力由第4 min时的8.2 kN/m下降到试验结束时的2.7 kN/m,跨中板带则由第4 min时的4.5 kN/m下降到接近0;平板无梁楼盖的板顶裂缝最终形成对角呈双曲线形,与传统塑性铰线理论的柱附近局部屈服线模式一致。
Fire resistance tests were carried out on two specimens of full-thickness reinforced concrete slab-free floor slabs. The in-plane (horizontal) displacements and out-of-plane (vertical) displacements of the slabs under fire were measured. Changes, the temperature distribution along the thickness of the concrete slab and the temperature change of the steel slab are analyzed. The results show that the temperature of the reinforced concrete slab subjected to fire on one side is non-linearly distributed along the thickness, and the temperature gradient increases rapidly with the increase of time. The presence of water such as capillary water and gel water causes the concrete to be produced at 100 ° C The water temperature not only affects the concrete temperature but also causes the burst of fire-affected concrete. When the water content is too high, the concrete will burst and the plate will be destroyed. The confining reaction force of both the upper plate and the middle plate With a significant change, the confining reaction force of the strip on the column decreased from 8.2 kN / m at 4 min to 2.7 kN / m at the end of the experiment, and that of the mid-plate decreased from 4.5 kN / m at 4 min To close to 0; finally, the plate crest of the slab-free slab floor is hyperbolic, which is consistent with the local yield line model near the traditional plastic hinge theory.