1            Rajesh P. Dhakal 1* , John B. Mander 1 and Naoto Mashiko 1 1 Department of Civil Engineering, University of Canterbury, Private bag 4800, Christchurch 8020, New Zealand *Corresponding author: Ph: +64/3/3642987 ext 7673; Fax: +64/3/3642578; E/mail: rajesh.dhakal@canterbury.ac.nz  A method is established to identify critical earthquake ground motions that are to be used in physical testing or subsequent advanced computational studies to enable seismic performance to be assessed. The ground motion identification procedure consists of: choosing a suitable suite of ground motions and an appropriate intensity measure; selecting a computational tool and modelling the structure accordingly; performing    on a nonlinear model of the structure; interpreting these results into 50 th (median) and 90 th percentile performance bounds; and identifying the critical ground motions that are close to these defining probabilistic curves at ground motion intensities corresponding to the design basis earthquake and the maximum considered earthquake. An illustrative example of the procedure is given for a reinforced concrete highway bridge pier designed to New Zealand specifications. Pseudodynamic tests and finite element based time history analyses are performed on the pier using three earthquake ground motions identified as: (i) a    (10% probability in 50 years) with 90 percent confidence of non/exceedance; (ii) a    (2% probability in 50 years) representing a median response; and (iii) a    representing 90 percent confidence of non/exceedance.  Performance Based Earthquake Engineering (PBEE), Seismic performance assessment, Pseudodynamic test, Critical ground motions, Incremental Dynamic Analysis (IDA), Confidence bounds, Time/history analysis, Design Basis Earthquake (DBE), Maximum Considered Earthquake (MCE)  In     (PBEE), seismic design is carried out through an iterative loop comprising the following four steps: (i) design the structure and detail it accordingly to satisfy prescribed performance requirements; (ii) assess the seismic performance of the designed structure; (iii) compare the expected performance against the prescribed requirements; and (iv) decide on the appropriateness of the designed structure. The second step; i.e. assessing the seismic performance; can be performed either through numerical analysis of the structure subjected to the design actions using an appropriate computational tool or by testing a scaled model of the structure or its components in the laboratory. Although physical tests are time and resource consuming, performance assessment by experimental means has its own merits. For example, an experimental approach avoids the assumptions/idealizations pertinent to the analytical modelling and it gives the most realistic indication of expected structural performance. In order to experimentally assess the seismic performance of structures, the applied loading/action to which the physical structural model is to be subjected to needs to be decided