酸性大气环境下锈蚀钢框架结构振动台试验研究

SHAKING TABLE TEST OF CORRODED STEEL FRAME STRUCTURE UNDER ACIDIC ATMOSPHERE ENVIRONMENT

为研究酸性大气环境下锈蚀钢框架结构的整体抗震性能,设计了2个不同锈蚀程度(S1、S2)的5层空间钢框架结构。利用气雾腐蚀箱对酸性大气环境进行人工模拟并对S2进行加速腐蚀(S1未锈蚀作为对比)。分别对2个结构进行振动台试验,测定了不同锈蚀程度钢框架结构的动力特性及加速度、位移、应变反应和破坏特征,研究了钢框架结构的地震响应随钢材锈蚀程度增大的变化规律。试验结果表明:锈蚀对整体结构的影响主要表现为:结构自振频率下降7.46%~9.76%,阻尼比、位移、应变增大,加速度反应、剪力响应明显降低;S1与S2的破坏形式基本相同,均为钢框架梁端部发生局部屈曲破坏,S2塑性变形程度较S1增大;8度多遇时,S1、S2地震响应相差不显著,随地震强度的增大,两者地震响应差异越明显;研究成果可为进行锈蚀钢框架的安全性评估提供试验支持。

In order to study the seismic performance of corroded steel frame structures under the acidic atmosphere environment, two five-layer steel frame structures （S1, S2）with different corrosion ratios were designed. The test of $2 was implemented accelerated corrosion by aerosol corrosion box （S 1 as the contrast test with no corrosion）, and then shaking table tests were carried out. The dynamic properties, acceleration, displacement, stain responses and failure characteristics of two structures were obtained. The rules of seismic performance of steel frame structures with different degree of steel corrosion were also studied. The results reveal the effect of corrosion on the structure, as natural frequency of the structure is decreased by 7.46%-9.76%, while the damping ratio, displacement, and strain increase and the acceleration and shear force reduce. The failure mode of S 1 and S2 is similar, as the structure has local bucking failure modes at end of beams, and the degree of plastic deformation of S2 is larger than that of S 1. Under the frequent earthquake with an intensity of 8, the seismic response of S2 and S 1 is similar, as the difference of seismic response between two structures is more obvious with the increase of the seismic intensity. The research results can provide experimental support for the safety assessment of corroded steel frame.