# Pedestrian Comfort Analysis and Parameterized Optimization Design for Raised Floors
###### Abstract
Consequently, to enhance the precision of research and to thoroughly evaluate the comfort of walking on the floor, it is essential to conduct investigations under conditions that closely mimic actual use. The intricate relationship between human bodies and structural support systems forms a sophisticated coupled dynamic, with each component influencing the other. Human activity imparts dynamic changes to the structural properties of the floor, notably increasing damping and slightly altering modal frequencies [23]. In scenarios characterized by coupled pedestrian loads, a heightened density of pedestrians prompts a decrease in both step frequency and average walking speed. Simultaneously, the peak response of floor vibrations diminishes with greater crowd densities [24]. Moreover, these structural vibrations impart a notable influence on pedestrian gait characteristics, including walking frequency, stride length, and speed. Such vibrations considerably attenuate the amplitude of walking force harmonics, especially those proximal to the vibration frequency [25]. This complex interplay warrants a nuanced understanding, as it holds significant implications for both structural design and pedestrian comfort. Moreover, it is essential to address the significance of establishing a pedestrian load model in investigating pedestrian comfort on a raised floor. Accurate pedestrian load curves can be obtained through the utilization of force plates [26; 27] and pressure-sensing insoles [28] for direct measurements. Pedestrian loads present a complex form of excitation, with various parameters such as step frequency, step length, body weight, walking direction, and ground contact time exhibiting significant variability among individuals. Simplification of the pedestrian load curve is imperative for a scientific examination of the impact of walking excitation on building structures. Given the periodic nature of walking forces, several pedestrian load models have been developed, including Fourier series models, self-excitation models, and effective impulse models [29]. [PERSON] et al. [30] compared multiple models of pedestrian load curves and proposed a triangular wave model for simplified computational analysis. Considering the randomness of walking paths and pedestrian loads, these pedestrian load curves do not perfectly align with real-world scenarios. [PERSON] et al. [8], using probabilistic statistical methods, incorporated the variability of walking paths and pedestrian loads into the calculation of pedestrian comfort on floors. However, more research is warranted to further delve into the study of pedestrian loads and establish quantitative standards to guide specific engineering practices. In light of the existing deficiency in quantitative analysis methods for assessing the comfort of walking on raised floors, this study has developed an index system to quantify pedestrian comfort on raised floors by synthesizing previous research findings and standards. The evaluation criteria focused on the natural frequency and peak acceleration of the most deformable point on the floor during walking. The pedestrian comfort of four distinct configurations of raised floors in a prefab bathroom unit was systematically analyzed. The natural frequency and mode distribution of the floor were determined through a combination of theoretical modal analysis and experimental modal analysis. Subsequently, the dynamic response of the floor was calculated utilizing walking loads as excitation. Furthermore, a raised floor size optimization design method, based on a multi-island genetic algorithm (MIGA), was introduced in this research. Correlation analysis was performed to investigate the impact of various components of the floor on pedestrian comfort. This innovative design method, without altering the material and structural components of the raised floor, achieved dual optimization of heat transfer performance and pedestrian comfort by adjusting parameters such as support foot spacing, beam shape and size, and support plate layer thickness.