Numerical verification of accelerometer-based assessment of hollow-type pretensioned concrete girder

In this paper, a vibration-based damage detection method was employed to assess a hollow-type prestressed concrete (BS12) girder in two different states using its dynamic characteristics. Once, the girder was assessed in as-built condition presenting undamaged sate. Next, the evaluation was carried out after the performance of four-point bending test that caused various cracks in the tension part of the girder. Despite that, change in physical parameter was minor due to high strength materials used in the girder and the cracks appeared were in negligible range. Yet, the method was able to demonstrate a detectable change in modal parameter (notably natural frequency) of the girder which is the function of physical properties. The aim of the study was to validate the preciseness of accelerometer-based method. To this purpose, the test was conducted three times for the initial intact and its following damaged states to have an accurate recorded response of the specimen. The measured data were compared with that acquired numerically using Finite-Element Method (FEM) Midas civil software. This paper concluded that even a minor damage can cause detectable shifts in modal parameters of the structure by presenting the well-matched results of both experimental and numerical methods of pre-damage and post-damage states of the girder.