An investigation of human comfort criteria for footfall induced floor vibrations

Human comfort is becoming a vital serviceability requirement when it comes to design of long-span floor systems, as evidenced by the development of international standards on human exposure to vibrations. This paper discusses experimental findings derived from dynamic testing of a real office floor of steel-concrete composite construction where annoying footfall-induced vibration had been reported by the floor tenants. The fundamental frequency of the problematic floor was determined using measurements obtained from a series of simple heel drop tests. The observed vibration levels of the floor under normal walking excitations was then benchmarked against acceptance criteria suggested by a number of widely used floor vibration design guides. From a human comfort perspective, it is found that the same floor can be classified as unacceptable by some guidelines but deemed extremely acceptable by the others. As response levels are translated inconsistently by various acceptance criteria, designers would hence be placed in a dilemma when deciding whether the existing floor really needs modification to enhance its serviceability.