Remote inventory and inspection of the truss bridge elements and connections using STS and UAV

Resumo

The traditional visual inspections, along with the remote Structural Health Monitoring (SHM) methods
are very valuable tools to keep the existing bridges safely in service. In the case of old structures with incomplete
documentation, verification of dimensions is also an essential aspect. Traditional on-foot or on-boat visual
inspections have many limiting factors. For large or tall structures, there is little to no possibility of visually
inspecting the entire structure without using lifts or other heavy machinery. This paper presents an attempt to use
a Scanning Total Station (STS) for the inspection and inventory of the dimensions of a truss railway bridge over
the largest river in Poland. Measurements were conducted using two methods: the direct method with the use of a
total station and the use of advanced geometric analyses of the collected point cloud. The field tests on the bridge
were preceded by tests in the laboratory, where the accuracy of the method was assessed. During the tests on the
bridge, a deviation from the actual geometry of the selected truss connection in relation to the old documentation
was detected. The credibility and scale of this deviation throughout the bridge span were confirmed by Unmanned
Aerial Vehicle (UAV) inspections.