The application of modern scientific methods and measuring techniques can extend the empirical knowledge used for centuries by violinmakers for making and adjusting the sound of violins, violas, and cellos.

Accessories such as strings and tailpieces have been studied recently with respect to style and historical coherence, after having been somehow neglected by researchers in the past. These fittings have played an important part in the history of these instruments, but have largely disappeared as they have been modernised. However, the mechanics of these accessories contribute significantly to sound production in ways that have changed over time with different musical aesthetics and in different technical contexts. There is a need to further elucidate the function and musical contribution of strings and tailpieces.

With this research we are trying to understand the modifications of the cello's sound as a consequence of tailpiece characteristics (shape of the tailpiece and types of attachments). Modal analysis was used to first investigate the vibration modes of the tailpiece when mounted on a non-reactive rig and then when mounted on a real cello where it can interact with the modes of the instrument's corpus. A preliminary study of the effect of the tailpiece cord length will be presented.

In the paper experimental investigation results of three elements are presented. Two of them were made of reinforced concrete. The strengthened bracket had the steel accessory mounted to cracked loaded corbel (while it was loaded to half ultimate force of the reference element), the reference one was tested without any accessory. The third corbel was the steel accessory mounted to the concrete column. Full scale corbels were 450 mm deep and 250 mm wide, steel accessory was 320 mm high. The aim of the research was to verify the following thesis: short corbels (shear slenderness a_c /h ≈ 0,3) can be strengthened by a steel accessory. Load carrying capacity of strengthened member increased by 40 %. The ultimate force obtained for the steel accessories mounted to concrete column was 66 % of reference value. While testing some observations and measurements (strain of reinforcement and concrete, development of cracking) were made which allowed to describe corbel behaviour under increasing load.