一般大气环境下低剪跨比RC框架梁抗震性能试验研究

EXPERIMENTAL RESEARCH ON ASEISMIC BEHAVIORS OF RC FRAME BEAMS OF LOW SHEAR SPAN RATION IN GENERAL ATMOSPHERIC ENVIRONMENT

为研究一般大气环境下受酸雨侵蚀RC框架梁的抗震性能,在人工气候模拟实验室对7个剪跨比为2.5的RC框架梁试件进行人工模拟酸雨环境(PH=3.0)加速侵蚀试验,随后对其进行拟静力试验,得到不同钢筋锈蚀程度和配箍率下框架梁抗震性能的衰减规律。结果表明:酸雨侵蚀初期,酸化深度较小时,钢筋尚未锈蚀,试件的承载力、刚度、延性和耗能能力略有增加;酸雨侵蚀后期,酸化深度接近钢筋表面时,钢筋开始锈蚀,且锈蚀程度随酸化深度的增大不断加重;随钢筋锈蚀率的增大,试件的强度、刚度、延性和耗能能力均发生不同程度的退化,表现为构件的承载力和变形能力下降;锈蚀程度相近时,随着配箍率的减小,试件的承载力和刚度不断减小,延性和变形恢复力也逐渐降低,抗震能力变弱。

To investigate aseismic behaviors of RC frame beams corroded in the common environment of acid rain, 7 RC frame beam specimens with shear span ratio of 2.5 were subjected to accelerated corrosion by simulated acid environment with PH=3.0. And then their quasi-static tests were carried out, thusly the failure modes and aseismic degradation characteristics of RC frame beams were obtained under different stirrup ratios and reinforcement corrosion ratios. The results reveal that：when acid depth is small in early acid erosion, steel is still not corroded, and the bearing capacity, stiffness, ductility, and energy dissipation of specimens increase slightly. Reinforcement begins to rust when acid comes near to steel surface with the aggravation of acid corrosion degree and the corrosion degree becomes worse with the increase of acid depth. The strength, stiffness, ductility and energy dissipation of frame beams were degraded with the raising of corrosion ratio of steel. Moreover, with the decrease of the stirrup ratio, the bearing capacity and stiffness of the specimen decreases continuously when in similar corrosion degree, and ductility and deformation restoring force is also gradually reduced, which indicates that its aseismic ability is becoming weak.