PVA-FRCC中长柱抗震性能与损伤分析

Seismic Performance and Damage Analysis of PVA-FRCC Medium-Length Columns

以剪跨比、配筋率和轴压比为研究变量,对7根聚乙烯醇纤维增强水泥基复合材料(PVA-FRCC)中长柱(以下简称PVA-FRCC柱)进行拟静力试验,研究了地震作用下试件的裂缝形态、变形、耗能和抗损伤能力。结果表明:PVA-FRCC柱具有优良的裂缝控制能力和卸载后裂缝闭合能力;PVA-FRCC具有较好的延性、较强的变形和耗能能力,其弹塑性极限位移角最大可达1/13;剪跨比较大的试件虽承载力较低,但由于PVA纤维的增韧作用,试件达到峰值荷载后具有优良的耐受变形能力和抗损伤能力;当配筋率提高时,柱的承载力、变形和抗损伤能力均提高;增大的轴压比明显降低了试件的变形、耗能和抗损伤能力。当PVA纤维体积分数为1%时,具有较小轴压比和适中剪跨比与配筋率的PVA-FRCC柱综合性能最优。本文提出的改进Park-Ang损伤模型符合边界条件,且反映的损伤发展趋势与试验现象相符,可较好地评价PVA-FRCC柱的损伤状况。

The pseudo-static test of 7 PVA-FRCC medium-length columns(hereinafter PVA-FRCC columns)was carried out with the shear span ratio,reinforcement ratio,and axial compression ratio as the research variables,and the crack morphology,deformation,energy consumption,and laser damage resistance of PVA-FRCC medium-length columns under seismic action were investigated.The results show that PVA-FRCC columns exhibit excellent crack control ability and closure ability after unloading,as well as remarkable ductility,deformation,and energy consumption capacity,with a maximum elastic-plastic limit displacement angle of 1/13.Specimens with higher shear span ratios have lower bearing capacity,while the reinforcing effect of PVA fibers endows superior deformation resistance and damage resistance after peak load.Furthermore,an increasing of reinforcement ratio leads to improve bearing capacity,deformation,and damage resistance of the PVA-FRCC columns,while an increasing of the axial compression ratio significantly reduces deformation,energy consumption,and damage resistance of specimens.PVA-FRCC columns with a smaller axial compression ratio and an appropriate shear span ratio and reinforcement ratio exhibit optimal performance when the PVA fiber volume fraction is 1%.To evaluate the damage status of PVA-FRCC columns,an improved Park-Ang damage model is proposed,which well satisfies the boundary conditions and reflects the trend of damage development which consistent with experimental results.