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

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.