The European collaborative programme on evaluating the performance of shaking tables

This paper describes a concerted performance appraisal of four of Europe's large shaking tables. Three of the shaking tables were capable of controlle d motion in all six degrees of freedom, while the fourth was constrained to move in the three translational axes only. The principal study was the fid elity of the input motion at the testpiece. At all four tables this was fou nd to be satisfactory, but, in one case, the time taken for the tuning proc ess was often more than one hour, and in all cases highly trained and exper ienced operators were required. Even so, the tuning process was 'out of rea l time', which required that the physical properties of the testpiece shoul d not change during the tuning process. This meant that controlled nonlinea r specimen behaviour could not be studied experimentally. This was a major drawback, since modern economic design requires use of nonlinear material p roperties, leading to progressive failure of redundant members, but not tot al collapse. The studies did, however, have a major beneficial effect in sh owing that existing control systems were out of date. Further research prog rammes were therefore started which have already had the major consequence of producing 'real-time' control of shaking tables.