| Damage assessment and condition evaluation of existing civil infrastructure systems are essential to the decision making in routine structural maintenance and disaster remediation. To determine internal conditions using surface strain measurement is a critical, real-life engineering problem, in view of the popularity of using surface strain measurement for structural health monitoring. The objective of this study is to develop a damage detection methodology to relate surface measurement (e.g., strain) with the internal condition (e.g., healthy or damaged) of structures using a singly-reinforced concrete beam as an example. Numerical approach is applied in conducting a parametric study in this research. A finite element model of a benchmark singly-reinforced concrete beam specimen was created using a commercial finite element analysis package, ABAQUS®. The model was validated in laboratory four-point bending test, using fiber optic strain sensor measurement. Artificial damages were modelled by rebars volume reduction, and four types of artificial damages are considered. From the simulation results, relationships between the change in surface strain and intensity of internal damage are developed. It is found that damage introduced in the rebar embedded in a reinforced concrete beam can be accurately located using the surface stress difference. Nonsymmetric damages yield more contour area of surface stress change than the symmetric damages. |
