考虑不均匀腐蚀影响的钢筋混凝土桥墩抗震性能研究

RESEARCH ON SEISMIC PERFORMANCE OF REINFORCED CONCRETE BRIDGE PIERS CONSIDERING INFLUENCE OF NONUNIFORM CORROSION

对于剪跨比较小的钢筋混凝土桥墩,近海环境下的腐蚀可能会改变结构破坏形态,研究箍筋纵筋同时腐蚀对抗震性能的影响十分必要。采用电化学加速腐蚀方法制备了4个剪跨比为2、不同腐蚀程度的桥墩,通过振动台试验研究腐蚀对桥墩抗震性能的影响。在地震激励作用下,对桥墩的破坏形态、自振周期、阻尼比、加速度和位移响应、累积残余位移及地震耗能能力等方面进行了分析。试验结果表明:随着地震强度的增大,腐蚀构件的耗能能力降低,抗震性能退化明显;无腐蚀桥墩的最终破坏形态是弯曲破坏,而腐蚀程度较为严重的桥墩在加载后期表现为纵筋过早屈服,部分箍筋无法为试件提供足够的抗剪承载能力,试件最终呈现出弯剪破坏形态。

For reinforced concrete piers with relatively small shear spans, corrosion in the offshore environment may change the structural damage form. It is necessary to study the effect of simultaneous corrosion on seismic properties. Four bridge piers with a shear span ratio of 2 and different degrees of corrosion were prepared by electrochemical accelerated corrosion methods. The effect of corrosion on seismic performance of bridge piers is studied by a shaking table test. Under the action of seismic excitations, the failure mode, natural vibration period,damping ratio, acceleration, and displacement response, accumulated residual displacement and seismic energy dissipation capacity of the bridge pier were analyzed. The results show that: as the earthquake intensity increases,the energy dissipation capacity of corroded components decreases, and the seismic performance degrades significantly. The ultimate damage form of non-corrosion piers is bending failure. The piers with more severe corrosion appear to yield prematurely in the later stage of loading. Some stirrups could not provide sufficient shear load capacity for the specimen. The specimen finally showed a bending-shear failure form.