An Aspect of Dynamic Human-structure Interaction

It is known that humans and structures interact. Humans can cause structures to vibrate, and excessive vibrations may occur if the motion frequency of humans coincides with a resonant frequency of the structural system. It is also known that stationary humans (such as humans sitting or standing on the structure) influence the dynamic behaviour and modal characteristics of the structure carrying them, whether being a grandstand, an office floor or similar. However, the interaction between the stationary humans and the structure is generally not well understood, and the paper addresses this interaction. Focus is on how modal characteristics of the structure, i.e. its frequency and damping, are influenced by the presence of stationary humans. Vertical vibrations are considered, and particular focus is given the influence of human posture on modal characteristics of the supporting structure. Insight into this area is obtained by carrying out experiments with a test floor carrying humans. The paper describes the conditions for the tests, the modal identification procedures, the test programme, and the results. NOMENCLATURE fF Floor frequency α Dynamic load factor g Acceleration of gravity ζF Floor damping m Mass of jumper t Time w Weight of person/crowd F Load on structure A..F Human postures