Identification and modelling of vertical human-structure interaction

Slender footbridges are often highly susceptible to human-induced vibrations, due to their low stiffness, damping and modal mass. Predicting the dynamic response of these civil engineering structures under crowd-induced loading has therefore become an important aspect of the structural design. The excitation of groups of pedestrians and crowds is generally modelled using moving loads but also the changes in dynamic characteristics due to human-structure interaction are found to significantly affect the footbridge response. The present contribution investigates the influence of the presence of the pedestrians onto the dynamic characteristics of the occupied structure by means of an extensive experimental study on a footbridge in laboratory conditions. The analysis shows that the natural frequencies slightly reduce due to the additional mass but more significant is the observed increase in structural damping. Similar observations are made on a in situ footbridge. This interaction is simulated using a coupled human-structure model in which the human occupants are represented by simple biomechanical models.

[1]  Guido De Roeck,et al.  REFERENCE-BASED STOCHASTIC SUBSPACE IDENTIFICATION FOR OUTPUT-ONLY MODAL ANALYSIS , 1999 .

[2]  Jeremy F. Burn,et al.  Biomechanically Inspired Modeling of Pedestrian-Induced Vertical Self-Excited Forces , 2013 .

[3]  Michael J. Griffin,et al.  The horizontal apparent mass of the standing human body , 2011 .

[4]  Michael J. Griffin,et al.  DYNAMIC RESPONSE OF THE STANDING HUMAN BODY EXPOSED TO VERTICAL VIBRATION: INFLUENCE OF POSTURE AND VIBRATION MAGNITUDE , 1998 .

[5]  Stana Živanović,et al.  Design and Construction of a Very Lively Bridge , 2013 .

[6]  Aleksandar Pavic,et al.  Experimental methods for estimating modal mass in footbridges using human-induced dynamic excitation , 2007 .

[7]  Michael J. Griffin,et al.  Mathematical models for the apparent masses of standing subjects exposed to vertical whole-body vibration , 2003 .

[8]  Stephen J. Wright,et al.  Numerical Optimization , 2018, Fundamental Statistical Inference.

[9]  Piotr Omenzetter,et al.  LONG SPAN STEEL PEDESTRIAN BRIDGE AT SINGAPORE CHANGI AIRPORT - PART 2: CROWD LOADING TESTS AND VIBRATION MITIGATION MEASURES , 2004 .

[10]  Paul Reynolds,et al.  Vibration serviceability of stadia structures subjected to dynamic crowd loads: A literature review , 2011 .

[11]  Edwin Reynders,et al.  System Identification Methods for (Operational) Modal Analysis: Review and Comparison , 2012 .

[12]  Aleksandar Pavic,et al.  Experimental identification and analytical modelling of human walking forces: Literature review , 2009 .

[13]  James M. W. Brownjohn,et al.  Modeling and simulation of human-floor system under vertical vibration , 2001, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[14]  James M. W. Brownjohn,et al.  Energy dissipation from vibrating floor slabs due to human-structure interaction , 2001 .

[15]  Paul Reynolds,et al.  Human-Structure Dynamic Interaction in Civil Engineering Dynamics: A Literature Review , 2003 .

[16]  Geert Lombaert,et al.  Characterisation of walking loads by 3D inertial motion tracking , 2014 .

[17]  Stephen P. Boyd,et al.  Convex Optimization , 2004, Algorithms and Theory of Computation Handbook.

[18]  Neil J Mansfield,et al.  Impedance methods (apparent mass, driving point mechanical impedance and absorbed power) for assessment of the biomechanical response of the seated person to whole-body vibration. , 2005, Industrial health.

[19]  Guido De Roeck,et al.  Reference-based combined deterministic–stochastic subspace identification for experimental and operational modal analysis , 2006 .

[20]  Filipe Magalhães,et al.  Damping Estimation Using Free Decays and Ambient Vibration Tests , 2010 .

[21]  Michael J. Griffin,et al.  Modelling resonances of the standing body exposed to vertical whole-body vibration: Effects of posture , 2008 .

[22]  Rik Pintelon,et al.  Uncertainty bounds on modal parameters obtained from stochastic subspace identification , 2008 .