基于参数离散化的梁式桥损伤识别方法

Damage identification method of girder bridge based on parameter discretization

针对梁式桥提出了一种基于参数离散化的损伤识别方法,并以结构动力指纹、实测位移、速度、结构刚度矩阵及其影响矩阵为变量,提出了全面损伤指标I1和精准损伤指标I2,通过数值模拟和实桥试验验证了该损伤识别方法的敏感性和抗噪性.结果表明,损伤指标I1和损伤指标I2均能有效实现梁式桥的损伤识别,且损伤指标I1具有更好的损伤敏感性和抗噪性,而损伤指标I2相对漏诊的可能性较低.在新沂河大桥损伤识别中,损伤指标I1能基本拟合梁式桥裂缝分布,较全面地反映出桥梁的损伤概况;而损伤指标I2对梁式桥中的重大损伤更为敏感,对于桥梁重大病害损伤识别的抗干扰性较高,能较准确反映桥梁结构的主要损伤.基于参数离散化的损伤识别方法可从本质上揭示梁式桥刚度损伤的数学形式,有效应用于梁式桥损伤识别中.

A damage identification method based on parameter discretization is put forward for girder bridges.Taking the structural dynamic characteristics,measured displacement,velocity,structure stiffness matrix and the corresponding influence matrix as variables,the comprehensive damage identification index I1 and the accurate damage identification index I2 are proposed.The sensitivity and anti-noise ability are verified by the numerical simulation and measured data.The results show that both the comprehensive damage identification index I1 and the accurate damage identification index I2 can be effectively applied in the damage identification of beam bridges.The sensitivity and the anti-noise ability of index I1 is better,and the probability of missed diagnosis of index I2 is lower.The damage identification results of Xinyihe Bridge show that index I1 can fit the distribution of fracture well and reflects the overview of damage.However,index I2 is much more sensitive to major damage and has an excellent anti-noise performance;therefore,it can reflect major damage accurately. The proposed method can essentially reveal the mathematic expression of stiffness damage,and can be applied in the damage identification of girder bridges.