Impact of stochastic representations of pedestrian actions on serviceability response

Abstract

Over the past 15 years, there have been some research outcomes in other disciplines, that could be used to produce new, more accurate, and realistic numerical models to characterise pedestrian loads and to significantly improve predictions of response for multiple pedestrian scenarios. However, the disconnection between fields has not facilitated this further research. Using this, the paper presents (1) a new sophisticated load model that includes the description of vertical and lateral loads, including pedestrian-structure interaction, (2) the numerical description of relationships to describe the key parameters of the proposed model, and (3) the evaluation of the effects of pedestrian characteristics that are relevant for serviceability response of footbridges. The proposed new load model enables inherent variability of individual pedestrian actions (intrasubject variability), probabilistic description of how pedestrian characteristics vary among subjects (inter-subject variability), and collective human behaviour (pedestrian-pedestrian interaction). Some of these characteristics are not currently considered in design approaches and can have a substantial impact upon structural response assessment. Finally recommendations are made for many of these characteristics to be introduced in analyses to evaluate the vibration serviceability limit state of footbridges in a more accurate and realistic manner.

A Statistical Approach for Modeling Individual Vertical Walking Forces

“…As an example, Rezende et al [18] demonstrated the impact of both the inter-and intra-subject variability on the tuned mass damper (TMD) efficiency through simulations involving pedestrian densities up to 0.5 ped/m 2 . Similarly, Ramos-Moreno et al [19] highlighted the importance of considering the step frequency variability for individuals in simulations with multiplepedestrian scenario (pedestrian densities of 0.2 ped/m 2 and 0.2 ped/m 2 ). To describe the intra-subject variability, the variation in the gait parameters induced by a single pedestrian step-by-step needs to be evaluated [16,20].…”

“…Unlike inter-subject variability, intra-subject variability has often been neglected as its impact on vibration levels was traditionally considered insignificant [16]. Nevertheless, more recent studies demonstrated the great impact of the variability of individual walking force on the accuracy of the predicted vibration response [17][18][19]. As an example, Rezende et al [18] demonstrated the impact of both the inter-and intra-subject variability on the tuned mass damper (TMD) efficiency through simulations involving pedestrian densities up to 0.5 ped/m 2 .…”

Interaction Phenomena to Be Accounted for Human-Induced Vibration Control of Lightweight Structures

“…Regarding human-induced loads, experimental campaigns using force plates (Parkhouse and Ewins, 2006), sensors (Moreu et al, 2020), shoe insoles (Wang H. et al, 2019), or computer vision approaches (Wang Y. et al, 2019), to mention a few, have been carried out to accurately characterize these actions. Thus, deterministic (Boniface et al, 2006;Heinemeyer et al, 2009) or stochastic (Casciati et al, 2017;Ramos-Moreno et al, 2020) models have been proposed over the years to predict the dynamic response of structures under the human actions. Codes and control design approaches consider that forces generated by human activities are the same on a flexible structure and on a rigid structure.…”