A Study Of Dynamic Forces Due To Human Movement On Stairs

In recent times there has been an improvement in computerized analysis and design of structures which have resulted in longer span and lightweight structures. The structures are strong enough to carry loads but due to their lightness and slenderness, they are more susceptible to vibration due to human movements. Structural engineers need to address the vibration issue and find the underlying reason and to solve or reduce the issue with knowledge and experience. The main objective of this research is to define the dynamic forces due to human movement on stairs. The data was the measurements of ground reaction forces (GRF) from several individuals ascending and descending a prototype rigid stair located at the Virginia Tech Vibration Testing Laboratory using an instrumented force plate to measure the exerted forces. The weight of each individual was also measured by the same force plate. Considering the periodicity of human excitation force, the Fourier Series parameters (Fourier Coefficients or Dynamic Load Factor (DLF) and corresponding phase angles) of the measured forcing functions were computed. Relationships between the DLFs and their associated phase angles as a function of the step frequencies were established.