Li Yong, Yu Zijie, Liu Yongqian
The Key Laboratory of Roads and Railway Engineering Safety Control, School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China.
Materials (Basel). 2023 Mar 20;16(6):2476. doi: 10.3390/ma16062476.
Using steel plates attached with epoxy resin adhesive to strengthen prestressed reinforced concrete bridges has become a common method to increase bearing capacity in engineering because of the simple technology, low cost and good strengthening effects. The strengthening method of steel plates has been gradually applied to repair damaged bridges in practical engineering. After a cross-line box girder bridge was struck by a vehicle, the steel bars and concrete of a damaged girder were repaired and strengthened by steel plates, and then the ultimate bending bearing capacity was studied through a destructive test. The results of the destructive test were compared with those of an undamaged girder to verify the effect of the repair and strengthening of the damaged girder. The results showed that the actual flexural bearing capacity of the repaired girder strengthened by steel plates was 1.63 times the theoretical bearing capacity, 36.7% more than that of the damaged girder and 95.3% of that of an undamaged girder. The flexural cracking moment of the repaired girder strengthened by steel plates reached 66.3% of that of the undamaged girder. The maximum crack width decreased by 24.6%, and the maximum deflection increased by 2.7%, compared with the undamaged girder when the repaired girder strengthened by steel plates finally failed. Moreover, this method of attaching steel plates can increase the ductility of bridges and reduce the degree of cracking. Additionally, the actual safety factor of the repaired girder was greater than three, and it had a large safety reserve.
由于技术简单、成本低且加固效果好，采用环氧树脂胶粘剂粘贴钢板加固预应力钢筋混凝土桥梁已成为工程中提高承载能力的常用方法。钢板加固方法已在实际工程中逐渐应用于受损桥梁的修复。一座跨线箱梁桥被车辆撞击后，对受损梁的钢筋和混凝土进行了修复并采用钢板加固，然后通过破坏性试验研究了其极限抗弯承载能力。将破坏性试验结果与未受损梁的结果进行比较，以验证受损梁修复加固的效果。结果表明，采用钢板加固后的修复梁实际抗弯承载能力为理论承载能力的1.63倍，比受损梁提高了36.7%，为未受损梁的95.3%。采用钢板加固后的修复梁抗弯开裂弯矩达到未受损梁的66.3%。与未受损梁相比，采用钢板加固后的修复梁最终破坏时最大裂缝宽度减小了24.6%，最大挠度增加了2.7%。此外这种粘贴钢板的方法可以提高桥梁的延性并降低开裂程度。另外，修复梁的实际安全系数大于3，具有较大的安全储备。
