混凝土梁桥动力特性对耐久性指标的灵敏度

Sensitivity of Concrete Girder Bridge Dynamic Behaviors on Durability Index

摘要:

根据简支梁的振动频率和振型函数，建立了基于监测信息条件下的可靠度功能函数.采用可靠性的灵敏度分析方法，研究材料参数和截面几何参数对混凝土梁桥振动频率的影响.理论分析表明，振动频率对钢筋弹性模量的灵敏度低于对混凝土弹性模量的灵敏度，对混凝土截面惯性矩的灵敏度低于对钢筋截面惯性矩的灵敏度.算例表明，振动频率对钢筋腐蚀的灵敏度高于对跨中损伤的灵敏度；当钢筋腐蚀程度和跨中损伤程度分别为5%，10%，15%和20%时，钢筋腐蚀引起的1阶振动频率变化率是跨中损伤引起的1阶振动频率变化率的1.94，1.85，1.80和1.74倍.

关键词:梁桥; 频率; 振型; 钢筋腐蚀; 损伤

Abstract:

According to frequency of vibration and vibration mode function of simply supported beam, the reliability functional function was established based on monitoring information. The reliability sensibility analysis method was used to study the influence of materials parameters and cross section geometry parameters on frequency of vibration. Theoretical analysis shows that the sensitivity of frequency of vibration on the reinforcement elastic modulus is lower than that on the concrete elastic modulus. The sensitivity of frequency of vibration on the moment of inertia of cross section of concrete is lower than that on the moment of inertia of cross section of reinforcement. The numerical example demonstrates that the sensitivity of frequency of vibration on the reinforcement corrosion is higher than that on the mid span damage. When the reinforcement corrosion degree and the damage severity are 5%, 10%, 15% and 20% respectively, the reinforcement corrosion caused by the first order frequency of vibration variation rate are 1.94 times, 1.85 times, 1.80 times and 1.74 times as much as that caused by mid span damage of the first order frequency of vibration variation rate.

Key words:girder bridge; frequency of vibration; mode shapes; reinforcement corrosion; damage