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加拿大一座已运营40年的4跨预应力混凝土简支C形梁桥受冲击荷载损坏,采用3层预应力碳纤维增强材料(CFRP)薄板进行加固。为研究预应力CFRP板锚固系统的可靠性和加固的有效性,进行锚固系统可靠性能的试验、理论和有限元分析。研究结果表明:锚固系统设计可靠;CFRP板的初始脱胶荷载稍低于目标预应力水平;牵引板端部应力集中明显,是导致脱胶的重要因素,建议在锚固设计中考虑牵引板端部的剪应力;加固后,桥梁抗弯、抗裂能力能恢复到未受损状态;相比受损状态,加固后边梁的挠度和内部预应力钢绞线应变都减小了5%;加固后各梁段间的荷载重新分配。AASHTO LRFD评估表明该桥加固后在设计车辆荷载下是安全的。
A 40-year-old 4-span prestressed concrete C-beam bridge in Canada that has been damaged for four years by impact load is reinforced with 3-layer prestressed carbon fiber reinforced plastic (CFRP) sheets. In order to study the reliability and reinforcement effectiveness of the prestressed CFRP plate anchoring system, the reliability, performance and anchorage system reliability of the anchorage system were tested. The results show that the design of anchorage system is reliable; the initial degumming load of CFRP board is slightly lower than the target prestress level; the stress concentration at the end of traction board is obvious, which is an important factor leading to degumming. After the reinforcement, the bending and cracking resistance of the bridge can be restored to the intact state. Compared with the damaged condition, the deflection of the reinforced side beam and the strain of the internal prestressing strand are reduced by 5% Section load redistribution. The AASHTO LRFD assessment shows that the bridge is safe to design under vehicle loads.