Dead load based damage identification method for long-term structural health monitoring

A novel damage identification procedure is presented that is ideally suited for long-term structural health monitoring of large civil structures. The procedure is based on the redistribution of dead load stress that occurs in a structure when damage takes place. The damaged structure is modeled using finite elements, in which the damage is represented by a section of reduced flexural rigidity. Forward analyses are first presented to show how the dead load is redistributed for different damage scenarios. The inverse damage identification problem is set up as a constrained optimization problem and solved using a real coded genetic algorithm. The proposed method correctly identified damage for a wide range of locations and damage severities. Results show that damage is difficult to identify when it is close to the inflection points of the structure, where the dead load strain is zero, and when the damage is not located between two sensors. The effect of measurement error is investigated.