【摘 要】
:
我国现役钢筋混凝土结构常因各种不利因素出现劣损致使结构承载性能下降。因此,亟需寻求一种高效经济的补强加固方法。嵌入式加固技术(Near Surface Mounted,NSM)是一种新兴的结构补强手段,结合延性加固材料铝合金,相关专家学者提出了铝合金嵌入式补强钢筋混凝土结构方法。为研究嵌入式加固混凝土梁的抗弯性能,本文开展了7根嵌入式补强钢筋混凝土梁的静力试验研究,建立了基于界面力学模型的嵌入式加
【基金项目】
:
国家自然科学基金项目(51868073);
论文部分内容阅读
我国现役钢筋混凝土结构常因各种不利因素出现劣损致使结构承载性能下降。因此,亟需寻求一种高效经济的补强加固方法。嵌入式加固技术(Near Surface Mounted,NSM)是一种新兴的结构补强手段,结合延性加固材料铝合金,相关专家学者提出了铝合金嵌入式补强钢筋混凝土结构方法。为研究嵌入式加固混凝土梁的抗弯性能,本文开展了7根嵌入式补强钢筋混凝土梁的静力试验研究,建立了基于界面力学模型的嵌入式加固梁承载力计算方法,具体研究内容如下:(1)完成了嵌入式补强钢筋混凝土梁抗弯性能试验,对比研究加固筋种类、加固量对加固混凝土梁抗弯性能的影响,分析了加固梁的破坏模式及破坏过程。试验结果表明,铝合金筋加固混凝土梁相比GFRP筋/铝合金筋混合加固梁以及PSB筋加固梁有更好的变形能力;因高强铝合金与结构胶弹性模量存在差异,导致加固筋-混凝土界面成为加固体系中的薄弱环节,致使在不采取附加锚固的情况下加固梁仍未能避免发生剥离破坏。(2)根据裂缝间距对嵌入式加固混凝土梁沿纵向进行分段建立界面分析单元,结合已有界面粘结应力分布模型,确定每个单元的粘结应力分布情况,并考虑混凝土-加固筋界面相对滑移的影响,提出了界面剥离承载力计算模型;通过限定边界条件对界面粘结应力控制方程重新求解,提出了简化后的界面剥离承载力计算模型。收集了19根发生界面剥离破坏的嵌入式加固混凝土梁的试验数据,与三种嵌入式加固梁剥离承载力计算模型进行对比分析。结果表明,所建立的根据裂缝间距对加固混凝土梁沿纵向进行分段的界面剥离承载力预测模型与所提出简化剥离承载力预测模型均有较高的精度。(3)基于静力平衡条件和应变协调关系,提出了不同破坏模式下嵌入式加固钢筋混凝土梁正截面承载力计算方法。在纵筋屈服前,基于有效惯性矩法建立了预测混凝土加固梁截面弯曲刚度的计算方法;纵筋屈服后,基于刚度解析法提出了混凝土加固梁截面的二次刚度计算式,建立了嵌入式加固梁跨中挠度计算方法,提出了加固梁荷载-跨中挠度简化全过程分析模型,并通过已有试验数据与理论模型进行了对比验证,分析结果表明二者吻合良好。
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