Report - PEER - University of California, Berkeley

4. OBJECTIVES AND OUTCOME OF STRUCTURAL TESTINGExperimental verification of the performance of structures subjected to earthquakeinput motions can be made through either shaking table (dynamic) tests or reactionwall(pseudo-dynamic) tests; however, if strain rate effects are important andcondensation to a reduced number of test DOFs is not realistic, dynamic testingshould be sought. On the other side, if large-full scale models should be considered,pseudo-dynamic testing (PSD) becomes the appropriate solution because complexnonlinear phenomena are often accurately simulated only at full or large model scales.Furthermore, expansion of the time scale makes up for much more handy tests, in thatthe tests can be stopped at any critical event and be re-started if necessary.Furthermore, PSD testing allows hybrid (physical and numerical) online simulation oflarge structures and systems to be carried out by substructuring techniques alreadyfamiliar to analysts.The basic objectives of earthquake testing of structures can be summarized as: (i)to check the accuracy of numerical models and to adjust/calibrate model parameters.(modeling of single components may not capture the behavior of a complete structuralsystem); (ii) to check structural performance for different input motion intensities(compare: demand, control variables and damage descriptions with capacity, limitstate characterization and, ultimately, to reach collapse of the structure, which isnormally associated with: (1) severe degradation of the structural properties often notaccurately simulated by the analytical models, and/or (2) brittle failure modes notcaptured by the models); (iii) to build confidence and trust on the performance of newstructural solutions, new design methods (e.g., new design codes) and innovativematerials, as well as to provide evidence on good or bad performance(demonstration).A test campaign normally involves a series of phases as described in Table 1.However, there is no standard procedure to conduct a test campaign. It should betailored to the research/demonstration/qualification scope and objectives.StageA0ABCDEFGTable 1. Full-scale seismic tests: stages and corresponding descriptionDescriptionDefine scope and objectives of the experimental campaignDefine a test specimen representative of a class of structuresSubject test specimen to EQ ground motions with specific intensities, I1, I2, I3, …,corresponding to characteristic lifetime exceedance probabilities (e.g., 50, 10 and 2%) andachieve collapse stage (Ultimate capacity)Record demands, in terms of deformation (e.g., drifts) and corresponding damage descriptionCarry out engineering quantification of damage (damage model, damage indices), taking intoaccount the problem of cumulative damage resulting from sequential testsCarry out calibration of damage cost functions relating drifts and/or damage indices with repaircostsCompare performances with corresponding performance objectivesIdentify implications on modeling, design methods and procedures, redefinition of performanceobjectives285