The Effect of Accelerometer Distance for Crack Assessment Using Vibration-Based Method

In order for reinforced concrete (RC) structures to remain structurally sound over time, damage detection is essential, particularly when the building has cracks. This pilot study examines the efficacy of a vibration-based technique that employs varying accelerometer distances to evaluate crack damage in reinforced concrete (RC) specimens. Four RC specimens were built; one was uncracked, and the other three had induced cracks with dimensions of 50 mm for length and 10 mm for width, and depths of 50 mm, 100 mm, and 150 mm, respectively. To test the efficacy of the vibration-based crack evaluation approach, a 10 mm crack was purposefully created in the concrete structure. As a way to ensure that the damage was significant enough to affect the vibration response while still being representative of typical structural damage scenarios, this crack size was selected. Using an impact hammer and accelerometers at 30 mm, 40 mm, 60 mm, and 120 mm distances, modal testing was carried out on specimens with different crack depths. The first mode natural frequency was ascertained by analyzing the experiment's data using ARTeMIS software. The findings show that the smallest deviations from the reference values determined by the multiplier method, which is based on the finite element method (FEM), are obtained at accelerometer distances of 40 mm and 120 mm. The locations of antinodes and nodes are represented by these distances, respectively. The data for uncracked specimens and those with a 120 mm crack depth show notable differences from the computed values, despite the fact that 30 mm is also close to both a node and an antinode. The accelerometers may have been positioned too closely together, which could have introduced signal errors. These results provide important information about how to best position sensors for vibration-based damage detection in reinforced concrete (RC) structures. In order to lay the groundwork for future studies into smaller or more intricate crack patterns, the goal is to assess whether this method can accurately identify and describe cracks.