Realistic simulation of the dynamic effects of walking pedestrians on structures is still a considerable challenge. This is mainly due to the inter- and intrasubject variability of humans and their bodies and difficult-to-predict loading scenarios, including multipedestrian walking traffic and unknown human-structure interaction (HSI) mechanisms. Over the past three decades, several attempts have been made to simulate walking HSI in the lateral direction. However, research into the mechanisms of this interaction in the vertical direction, despite its higher likelihood and critical importance, is fragmented and incoherent. It is, therefore, difficult to apply and codify. This paper critically reviews the efforts to date to simulate walking HSI in the vertical direction and highlights the key areas that need further investigation.

Predicting the effect of walking traffic on structural vibrations is a great challenge to designers of pedestrian structures, such as footbridges and floors. This is mainly due to the lack of adequate design guidelines, which in turn can be blamed on poor research findings. Even the fundamental data are very rare and limited. This study proposes a new and more reliable method for serviceability assessment of the vertical vibrations induced by multi-pedestrian walking traffic. Key novelties include modelling the natural variability of the walking forces and the human bodies, as well as their individual interaction with the supporting structure at their moving location. Moreover, a novel approach to vibration serviceability assessment (VSA) is proposed based on the actual level of vibration experienced by each pedestrian, rather than the typical maximum vibration response at a fixed point. Application of this method on two full-scale footbridge structures have shown that, with a suitable calibration of human model parameters, the proposed method can predict the occupied structure modal frequency with less than 0.1% error and - more importantly - modal damping ratio with less than 1% error. The new method also estimated the structural responses with considerably less error (5–10%) compared to a selection of current design guidelines (200–500%). The proposed VSA method is not suitable for hand-based calculations. However, if coded and materialised as a user-friendly software, it can be incorporated into design guidelines and used by consultants in everyday engineering practice

Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the ‘accuracy’ and ‘practicality’ of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1) methods based on measured kinematic data; (2) methods based on measured plantar pressure; and (3) methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1) reducing the size and price of tri-axial load-cells; (2) improving the accuracy of orientation measurement using IMUs; (3) minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4) increasing the durability of pressure insole sensors, and (5) enhancing the robustness and versatility of the ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment.