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为了研究高温后钢筋再生混凝土梁的受力性能,以再生粗骨料取代率、历经最高温度、混凝土强度、剪跨比为变化参数,设计了34个试件(其中高温后试件26个,常温对比试件8个)进行静力加载试验。观察了试件的破坏过程及其破坏形态,得到了烧失率、荷载-挠度曲线、截面应变分布、峰值荷载、峰值挠度等受力性能指标,分析各参数对其承载能力、挠度、延性、损伤等的影响。同时,对高温后钢筋再生混凝土梁受弯及受剪承载力的计算公式进行了推导。研究结果表明:高温后钢筋再生混凝土梁的破坏形态与其在常温下的相似,根据剪跨比的不同,发生了剪切斜压破坏和弯曲破坏;高温后试件的烧失率在0.44%~8.95%之间,随着温度和取代率的提高,烧失率逐渐增大;高温后钢筋再生混凝土梁的剩余承载力、峰值挠度及延性均不低于高温后普通钢筋混凝土梁;随着取代率的增大,承载力和延性呈先提高后降低的趋势,峰值挠度和损伤则逐渐增大;温度越高,承载力、峰值挠度和延性越低,损伤越重;剪跨比的增大使其承载力降低,峰值挠度增大;提高混凝土强度,能有效提高高温后再生混凝土梁的承载力,减小其峰值挠度。
In order to study the mechanical behavior of reinforced concrete beams after high temperature, 34 samples (including 26 samples after high temperature, Room temperature contrast test pieces 8) static load test. The destructive process and failure mode of the specimens were observed. The mechanical properties of the specimens such as the burning loss rate, load - deflection curve, cross - sectional strain distribution, peak load and peak deflection were obtained. The influence of various parameters on the bearing capacity, deflection, ductility, Damage and other effects. At the same time, the formulas for calculating the flexural and shear capacity of reinforced concrete beams after high temperature are deduced. The results show that the failure mode of RC beams after high temperature is similar to that at normal temperature. The shear baroclinic failure and bending failure occur under different shear-span ratios. The loss after burning at high temperature is between 0.44% 8.95%. With the increase of temperature and substitution rate, the burning loss rate gradually increases. The residual capacity, peak deflection and ductility of reinforced concrete beams after high temperature are not lower than that of common reinforced concrete beams after high temperature. With the substitution of The bearing capacity and the ductility increase first and then decrease, the peak deflection and damage increase gradually. The higher the temperature is, the lower the bearing capacity, the peak deflection and the ductility are, and the heavier the damage is. The greater the shear span ratio is The bearing capacity decreases and the peak deflection increases. Increasing the concrete strength can effectively increase the bearing capacity of regenerated concrete beams after high temperature and reduce the peak deflection.