钢板加固锈蚀RC梁短期挠度计算方法和试验

Calculating Method and Test Research of Short-term Deflection of Corroded RC Beam Strengthened by Steel Plate

为了研究锈蚀RC梁加固后变形性能,借助微元法思想,将加固锈蚀RC梁划分成有限单元,考虑锈蚀钢筋与混凝土之间的黏结强度退化以及退化后两者之间的滑移,提出了一种基于裂缝之间锈蚀钢筋和加固钢板组合伸长长度计算钢板加固锈蚀RC梁短期挠度计算方法,分析了钢板厚度和保护层厚度对锈蚀加固梁变形性能的影响。设计制作了9片锈蚀加固梁,并采用静载试验验证了理论模型。分析结果表明:理论模型能够较准确地预测锈蚀加固梁荷载-挠度曲线;在保护层厚度相同的条件下,当两试验梁平均锈蚀率相差超过1%时,锈蚀率是影响挠度发展的主要因素,挠度随平均锈蚀率增大而增大,当试验梁平均锈蚀率相差小于1%且两主筋锈蚀均匀时,挠度随钢板厚度增加而减小;在钢板厚度相同的条件下,荷载值大于50kN后两试验梁挠度随保护层厚度增加而减小。

In order to investigate the deformation behavior of corroded RC beam after strengthened,using infinitesimal method,dividing the reinforcement corroded RC beam into finite element,considering the bond strength degradation and slippage after degradation between corroded steel bar and concrete,a method that calculates short-term deflection of the corroded RC beam strengthened by steel plate was presented based on the combination elongation of corroded steel bar and reinforced steel plate between cracks,and the effects of thickness of steel plate and cover on deformation behavior of corroded strengthened beam were analyzed.Nine pieces of corroded and strengthened RC beams were designed and a static load test was used to verify theoretical model.The results show that the theoretical model can accurately predict loaddeflection curve of corroded and strengthened RC beam.Under the condition of the same coverthickness,when the difference of average corrosion rate of the two test beams exceeds 1%,the corrosion rate is the main factor affecting the development of deflection and the deflection increases with the increase of average corrosion rate.When the difference of average corrosion rate is less than 1% and the corrosion between two main steels is uniform,the deflection decreases with the increase of the thickness of steel plate.Under the condition of the same thickness of steel plate,the deflection decreases with the increase of cover thickness after the load exceeds 50 kN.