POUNDING BETWEEN BRIDGE DECKS: COMPUTATIONAL DETAILS AND RESULTS

Abstract. The observation of damage to structures, either buildings or bridges, due to earthquake induced pounding, dates back to early San Fernando (1971) and Mexico City (1985) post-earthquake reconnaissance reports. Recent ground shakings that have struck Italian territories have renewed the awareness of the necessity to clarify some aspects related to the pounding-induced forces acting on the bridge and viaduct piers. Historically pounding has been studied by either of two approaches, that are: 1) the stereo-mechanical approach, based on the physical laws of the impact phenomenon and the definition of a restitution factor, and 2) the force-based approach, based on the definition of the local force due to impact. Moreover, impact can be either soft or hard, depending on the amount of earthquake-induced energy dissipated locally through the damage of the colliding bodies. In this study, pounding response of two linear SDOF (Single Degree Of Freedom) systems has been studied through different models, namely: 1) Linear Spring, 2) Kelvin-Voigt, 3)Hertz, 4) Hertz-damp and 5) Stereo-mechanical model. Those models have been applied using both backward and forward spectrum-compatible and artificially generated ground motions. After introducing 1) the details of each of those models, 2) the main differences among them, and 3) the numerical computational strategy implemented, the main results are presented. Among these latter, being the early results of an exploratory and propaedeutic work for a Doctoral Thesis, the pounding-inducted response spectra, either in terms of peak displacement or pounding force, are developed.

[1]  S. L. Dimova Numerical problems in modelling of collision in sliding systems subjected to seismic excitations , 2000 .

[2]  Nawawi Chouw,et al.  Experimental investigation of spatially varying effect of ground motions on bridge pounding , 2012 .

[3]  K. T. Chau,et al.  Pounding of structures modelled as non‐linear impacts of two oscillators , 2001 .

[4]  Shehata E. Abdel Raheem Pounding mitigation and unseating prevention at expansion joints of isolated multi-span bridges , 2009 .

[5]  Vitelmo V. Bertero Observations on Structural Pounding , 1987 .

[6]  Lawrence F. Shampine,et al.  The Art of Writing a Runge-Kutta Code, Part I , 1977 .

[7]  Anat Ruangrassamee,et al.  Relative displacement response spectra with pounding effect , 2001 .

[8]  Chris P. Pantelides,et al.  LINEAR AND NONLINEAR POUNDING OF STRUCTURAL SYSTEMS , 1998 .

[9]  Nawawi Chouw,et al.  Required separation distance between decks and at abutments of a bridge crossing a canyon site to avoid seismic pounding , 2009 .

[10]  Reginald DesRoches,et al.  A Hertz contact model with non‐linear damping for pounding simulation , 2006 .

[11]  John R. Rice,et al.  Numerical methods, software, and analysis , 1983 .

[12]  Hans W. Reinhardt,et al.  LOAD-TIME RESPONSE OF COLLIDING CONCRETE BODIES , 1991 .

[13]  Andreas J. Kappos,et al.  Seismic Response of Adjacent Buildings with Similar or Different Dynamic Characteristics , 1994 .

[14]  Jinping Ou,et al.  Experimental and analytical study on pounding reduction of base‐isolated highway bridges using MR dampers , 2009 .

[15]  R. Jankowski Pounding force response spectrum under earthquake excitation , 2006 .

[16]  K. T. Chau,et al.  Experimental and theoretical simulations of seismic poundings between two adjacent structures , 2003 .

[17]  Robert Jankowski,et al.  Non‐linear viscoelastic modelling of earthquake‐induced structural pounding , 2005 .