UHPC双柱式桥墩抗震性能敏感性分析

Parametric Analysis of Seismicity of Two-Column UHPC Piers

为研究超高性能混凝土(UHPC)双柱式桥墩抗震性能的参数敏感性,选取经过模拟验证的UHPC材料本构模型,采用Abaqus软件建立桥墩有限元模型,基于Pushover分析法分析纵筋配筋率、钢筋强度、钢纤维掺量和轴压比对UHPC桥墩抗震性能的影响规律,并与普通混凝土(NSC)桥墩进行对比。结果表明:在相同的纵筋配筋率和钢筋强度条件下,UHPC可降低桥墩塑性损伤强度,减小损伤区域,UHPC桥墩的最大墩底抗剪承载力是NSC桥墩的2倍以上,具有更好的抗震性能;纵筋配筋率和钢纤维掺量的增加对UHPC桥墩的最大墩底抗剪承载力及延性性能有明显的提升,纵向配筋率的影响更明显;提高钢筋强度可显著提升桥墩的最大墩底抗剪承载力,但对延性性能的影响较小;增大轴压比可提高桥墩的最大墩底抗剪承载力,但也会降低桥墩的延性性能。

In this paper,the parametric sensitivity of seismicity of two-column ultra-high performance concrete(UHPC)pier is studied.A constitutive model of UHPC material that has been numerically verified is selected,and a finite element model of the two-column UHPC pier is developed in Abaqus to analyze the influences of longitudinal reinforcement ratio,reinforcement strength,steel fiber content and axial compression ratio on the seismic performance of UHPC pier,using the Pushover method.The data of normal strength concrete(NSC)pier are taken for comparison.It is shown that under the same longitudinal reinforcement ratio and reinforcement strength,UHPC can reduce the plastic damage degree and damage scale of the pier,the maximum pier-bottom shear strength of UHPC pier is over two times of that of the NSC pier,indicating superior seismicity.Increasing the longitudinal reinforcement ratio and steel fiber content results in significant improvement of the maximum pier-bottom shear strength and ductility,where the influence of the longitudinal reinforcement ratio is more notable.Increasing the reinforcement strength leads to remarkable increase of the maximum pier-bottom shear strength,but minimal variation of the ductility of the pier.Increasing the axial compression ratio can improve the maximum pier-bottom shear strength of the pier,but likely to cause decreased pier ductility.