纤维布加固墩接木柱轴压试验

Experimental study on axial compression characteristics of spliced wood columns strengthened with FRP sheets

为探究外包纤维增强复合材料(FRP)加固墩接木柱的加固效果和工作机制,考虑不同纤维布和不同墩接方式等因素影响,开展10根墩接木柱的轴压加载试验。对比分析3种FRP布(AFRP,BFRP,CFRP)、4种不同墩接方式(巴掌榫、刻半榫、抄手榫和直榫)下加固柱的破坏模式和力学性能。结果表明:未采用FRP布加固的传统墩接柱表现为拼接缝木材开裂和开裂后的墩接区木材压屈折断,而FRP布加固后,墩接区整体性良好,破坏主要发生在墩接口,表现为木材压溃和纤维布褶皱;传统墩接柱承载力仅恢复至42%~69%,刚度恢复至43%~65%;FRP布加固后,轴压承载力可恢复至完好木柱的75%~100%,刚度可恢复至66%~107%,延性提升24%~96%,加固柱轴压性能和变形能力得到有效的恢复或提高,且刚度退化不明显;此外,有限元仿真得到的荷载位移曲线及力学指标与试验结果吻合良好。FRP加固墩接木柱的轴压力学性能良好,可为传统木结构建筑的修缮和木柱的墩接加固提供借鉴和参考。

In order to explore the reinforcement effect and working mechanism of spliced wood columns strengthened by fiber reinforced polymer,the axial compression tests of 10 reinforced wood columns were carried out considering the influence of different fiber sheets and splicing methods.The failure modes and axial compressive properties of reinforced columns under three kinds of FRP sheets(AFRP,BFRP,CFRP)and four kinds of splicing methods(tenon joint,keban tenon joint,mortise joint,straight tenon joint)weree compared and analyzed.The results indicated that the traditional pier jointed columns without FRP reinforcement show the cracking of jointed timber and local buckling fracture after cracking.However,after FRP reinforcement,the integrity of the pier joint area is good,while the failure mainly occurred at the interface between the upper and lower piers,which was manifested as wood crushing and fiber cloth folding.The bearing capacity and stiffness of unconstrained pier joints were only recovered to 42%-69% and 43%-65% respectively.After the FRP reinforced pier was connected to the wooden column,the axial compression capacity can be restored to 75%-100% of the intact wooden column,the stiffness can be restored to 66%-107%,the ductility can be improved by 24%-96%,and the axial compression bearing capacity and deformation capacity of the wooden column can be effectively restored or improved.In addition,the stiffness degradation was not obvious.The load displacement curves and mechanical properties obtained by simulation were in good agreement with the experimental results.In conclusion,the spliced timber columns reinforced by FRP sheets had good mechanical properties,which can provide reference for the repair of traditional timber structures and the splicing of wooden columns.