1 LOADING HISTORIES FOR CYCLIC TESTS IN SUPPORT OF PERFORMANCE ASSESSMENT OF STRUCTURAL COMPONENTS

The need for comparable loading histories for seismic acceptance testing is becoming more prevalent as (a) performance-based design, which requires quantification of performance, is becoming a more widely accepted alternative to routine code design, (b) more and more innovative performance enhancement systems (e.g., buckling restrained braces) hit the engineering market, and (c) globalization becomes a widely accepted concept that necessitates globally accepted performance standards. Present codes, standards, and guidelines make reference to the need for performance assessment through testing, but with few exceptions (e.g., AISC 341-05 and testing of base isolation systems in ASCE 7-05) they remain mostly silent on testing and acceptance criteria to be used for this purpose. This paper provides a summary of (a) the background behind several of the presently employed cyclic loading histories, (b) basic concepts that should be considered in the development of loading histories, and (c) recent developments that point towards the need for modifications or expansion of presently employed loading protocols. WHY DO WE HAVE TO BOTHER WITH LOADING PROTOCOL