As a consequence of the failures experienced by the Cau Cau Bridge, Chile, the Ministry of Public Works of Chile entrusted the performance of a series of tests to this structure, which included invasive and non-invasive tests, load tests and various experimental and numerical analyzes to generate a detailed structural diagnosis. This paper reports the main results of non-invasive tests carried out on the reinforced concrete elements of this structure. Special geophysical tests using high-frequency Ground Penetration Radar, the use of traditional non-invasive methods, as well as the use of remote sensing methods based on high-range Terrestrial Laser Scanning for 3D modeling in conditions with and without loading are highlighted and detailed. Results show the advantages related to the great precision, speed and reliability of the use of these non-invasive methods as support for an opportune structural diagnosis of bridges.