Structural health monitoring of a modular tensegrity bridge

Tensegrity structures still represent a relatively new field of research in civil engineering; in particular, if on one hand the design of these structures, including static and dynamic analysis, has been explored by researchers, structural health monitoring is still an almost completely new topic to research about. The main purpose of this dissertation is to evaluate the feasibility of structure health monitoring or damage detection in tensegrity structures using output-only vibration measurements. The changes in the natural frequencies of the structure, which is represented by a modular pedestrian tensegrity bridge designed on purpose for this study, have been evaluated through changes in damage scenarios. The damage detection consequently leads to an optimal sensor positioning within the structure, obtaining as main result the number of sensors and, also, an approximate location of the sensors’ position. The minimum number of uniaxially sensors needed to detect the damage within the structure is 32: considering that the analysed cases of sensors’ number vary between 8 and 128, the result, which can be considered low, could be related to the size of the structure, which is relatively small. The location of sensors’ position has been detected as uniformly distributed in the tension cables, that represent the part of the structure most affected by every type of considered damage. Therefore, some proposals for a more specific study of the sensors’ location have been pointed out as possible future developments of this dissertation. It is important to highlight that the obtained results are mainly related to the analysed structure: the found number of sensors and their location is therefore valid only for the specific case of a modular tensegrity bridge. Nevertheless, this dissertation can represent a basis for this type of study, adapting the developed method to a different type of tensegrity structure.