独柱双层高架桥墩柱振动台试验研究Ⅱ:结构地震反应

Shaking Table Tests on Single-Column-Bent Double-Deck Viaduct Pier Model-Ⅱ:Structural Seismic Response

对独柱双层高架桥墩柱模型进行了模拟地震振动台试验,测试了结构水平向加速度、位移等反应数据,据此计算了墩底和墩身突变截面的地震弯矩,分析了结构损伤发展趋势。结果表明:独柱双层高架桥在水平方向的地震反应主要取决于对应方向前2阶振型贡献;墩柱开裂后,随调幅地震波的次第输入,结构损伤指标随关键自由度最大地震位移增长呈分段线性、梯级上升趋势,并在接近屈服前收敛为常数,此时墩柱截面有效刚度宜根据截面弯矩曲率关系分析确定。

On the shaking table a series of simulative seismic waves are input to simulate a single-column-bent double-deck viaduct pier model with structural seismic responses, including the horizontal accelerations and displacements, etc. The seismic bending moments at the column base and mutation section of pier are evaluated, and the developing trend of structural damage is analyzed. The results indicate that：the horizontal seismic response of single-column-bent double-deck viaduct mainly lies on the contributions from the first two free-vibration modes in the corresponding direction;during the ordinal input of amplitude-modulated seismic waves, damage index of the cracked structure increases piecewise linearly with magnification of the maximum seismic displacements along the key degrees of freedom, and levels off when the expected plastic hinge area approximates yielding state, then the column cross-section effective bending rigidity might be reasonably decided through sectional moment-curvature analysis.