预应力高强钢绞线网加固钢筋混凝土板的试验研究

采用新型张拉锚固系统对钢绞线网施加预应力,研究预应力水平值对板加固效果的影响规律。对3块不同预应力水平加固板、1块非预应力加固板和1块对比板进行抗弯试验研究。试验结果表明:较对比板,预应力加固板的承载力、截面刚度大幅度提高,裂缝宽度明显减小;较非预应力加固板,其开裂荷载显著提高,屈服荷载、极限荷载、截面刚度均有提高,裂缝宽度减小;随预应力水平的提高,加固效果、钢绞线强度的利用率明显提高。对钢绞线的预应力损失进行分析,提出预应力加固板承载力的计算公式,计算结果与试验值吻合良好,可作为预应力钢绞线抗弯加固混凝土板理论分析和设计的参考。预应力高强钢绞线加固技术解决了非预应力加固方法钢绞线应变滞后、发生剥离破坏、高强度利用率低等缺点,是一种主动高效的加固技术,具有较高的推广应用价值。

Experimental study of reinforced concrete slabs strengthened with prestressed high strength steel wire mesh

The performance of reinforced concrete slabs strengthened with high strength steel wire mesh at different prestress levels of a new tension and anchor system is studied.Three slabs reinforced with high strength steel wire mesh at different prestress levels were tested and compared with one original reinforced concrete slab and one non-prestressed reinforcement slab.Test results show that the load-bearing capacity and the exural stiffness of the slabs strengthened with prestressed steel wire mesh were greatly improved and the crack width was obviously reduced if compared with the original slab.Comparing with the non-prestressed reinforcement slab,the load-bearing capacity and the flexural stiffness of the slabs strengthened with prestressed steel wire mesh were increased,the cracking load was significantly increased,and crack width decreased.By raising the prestress level of steel wire mesh,the reinforcement effect and the efficiency of utilizing the steel wire strength was improved.The prestress loss of steel wire was analyzed,and formulas were proposed to predict the load-bearing capacity of reinforced concrete slabs strengthened with different prestress levels of steel wire mesh.The theoretical results agree well with the experimental ones,and can be used for theoretical analysis and design of prestressed steel wire mesh for strengthening concrete structures.The prestressed steel wire reinforcement technology is an effective reinforcement technique,because it can resolve the defects of strain lag,peeling of the strengthened layer and the low level of utilizing the strength of steel wire.