At German ports and waterways, there are approximately 3,000 km of shoreline walls and about 2,500 km of traffic structures. As these structures have mostly reached an advanced age, it is essential to know whether they are still load-bearing. Therefore, these structures must be examined for their reliability.
The common method to carry out this examination has been to deploy divers to inspect the walls underwater. This is very time-consuming, especially given that underwater light conditions in German ports are often poor. To overcome these disadvantages, sheet pile walls can also be surveyed using a multi-sensor system with a multi-beam echo sounder (MBES). This system measures the walls under water using sound waves and provides a point cloud of the structure.
To better assess and predict the reliability of the measurement data, it is essential to understand how various influencing factors – such as measurement distance, incidence angle, and surface roughness – affect the MBES measurements. Therefore, test walls with different geometric shapes, surface materials, and holes of varying size and shape were constructed. Based on the known geometry, hole positions, and dimensions, various characteristics were analyzed, with particular focus on the noise level and resolution capabilities of the MBES.