A Refined Model for Human Induced Loads on Stairs

Abstract

The tendency in modern architecture to lightweight and slender design of pedestrian structures is leading to an increased susceptibility to vibrations. Correspondingly, the evaluation of serviceability of pedestrian structures against vibrations due to human induced loads has gained more and more importance. Studies investigating corresponding action effects, usually focus on locomotion forms performed on a plane surface, e.g. jumping, running, walking. Information on the loads induced by ascending or descending stairs is scarce. In [1] a load model is presented which is based on a perfect repetitive single-foot load pattern leading to integer harmonic load contributions. Differences in the locomotion parameters for the left and the right foot are not considered leading to a loss of important information.

Based on experiments with a stair test section, this study investigates the load process due to descending and ascending stairs including the imperfections in the locomotion parameters. The dimension of stair rise and tread depth may have an influence on the harmonic load amplitudes. This is analyzed by experiments with different stair geometries. The paper discusses the random deviations in the locomotion process which may lead to additional intermediate harmonic load contributions. Furthermore, the randomness in the vertical load amplitudes in regard to the basic frequency content is analyzed.