Understanding the dynamic response of a structure or structural element can be a daunting task, particularly for practising engineers normally only concerned with the static design of structures. Many structural engineers will be familiar with the dynamic response of simple single-degree-of-freedom (SDOF) models. However, very few structures will correspond directly to such a form, which usually means computerised solutions are embarked upon, structures are radically altered, possibly needlessly, or problems passed to
dynamics specialists.
This paper simplifies the analysis to provide arithmetic solutions and a means of understanding the dynamic response of a structure. It also provides a means to verify computer modelling and estimate the characteristics (mass, stiffness and damping) of a TMD to address any residual problematic dynamic response. This enables the design provision for the additional weight attached to the structure and the required space, if a TMD is deemed to be necessary. A worked example of a simply supported welded steel box girder footbridge is presented.