Variation Patterns of Individual Evacuation Speed and Gait Parameters in High-Rise Building Staircases Under Different Evacuation Directions

Evacuation is an important research topic in building safety, urban public safety, and emergency management. Evacuation speed is a core parameter determining evacuation time and therefore has important scientific value. To reveal the variation patterns of gait parameters during staircase evacuation, this study conducted individual evacuation experiments on a staircase with a vertical height of 51.1 m. Each volunteer performed two consecutive evacuation phases with a 2 min rest between the phases, resulting in a cumulative evacuation height of more than 100 m. The evacuation speed, step length, and step time of 25 males and 25 females were measured under upward and downward evacuation conditions. The variation patterns of gait parameters under different evacuation directions were systematically compared, and the effects of resting at a similar height on the refuge floor were further analyzed in terms of evacuation speed and gait parameters. The results showed that the average evacuation speeds of both males and females exhibited an overall decreasing trend characterized by “faster decrease early and slower decrease later” during both upward and downward evacuation, while the decreasing trend was more gradual during downward evacuation. Although the variation patterns of gait parameters differed between upward and downward evacuation, the increase in step time was consistently the primary factor contributing to the decrease in evacuation speed. Specifically, during upward evacuation, the initial decrease in evacuation speed was jointly influenced by step time variation (65–80%) and step length variation (20–35%). As the evacuation process progressed, the relative contribution of step time variation further increased (>80%). In contrast, downward evacuation was relatively consistently dominated by step time variation (>90%). The rest promoted a certain degree of recovery; however, its recovery effect on step length during downward evacuation was not significant. This study revealed the characteristic differences and adjustment patterns of gait parameters during upward and downward evacuation from the perspective of gait parameters, thereby extending the microscopic perspective of staircase evacuation behavior research. The findings provide a scientific basis for high-precision evacuation process prediction, potential risk identification, and optimization of emergency management strategies for similar staircase evacuation scenarios.