SUMMARYStructural damage in buildings designed according to the dissipative design philosophy can be significant, even under moderate earthquakes. Repair of damaged members is an expensive operation and may affect building use, which in turn increases the overall economic loss. If damage can be isolated to certain dissipative members realized to be removable following an earthquake, the repair costs and time of interruption of building use can be reduced. Dual structural configurations, composed of a rigid subsystem with removable ductile elements and a flexible subsystem, are shown to be appropriate for the application of removable dissipative element concept. Eccentrically braced frames with removable links connected to the beams using flush end-plate bolted connections are investigated as a practical way of implementing this design concept. High-strength steel is used for members outside links in order to enhance global seismic performance of the structure by constraining plastic deformations to removable links and reducing permanent drifts of the structure.

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Pre-and post-test analyses of the structural response of a three-storey asymmetric reinforced concrete frame building were performed, aimed at supporting test preparation and performance as well as studying mathematical modelling. The building was designed for gravity loads only. Full-scale pseudo-dynamic tests were performed in the ELSA laboratory in Ispra. In the paper the results of initial parametric studies, of the blind pre-test predictions, and of the post-test analysis are summarized. In all studies a simple mathematical model, with one-component member models with concentrated plasticity was employed. The pre-test analyses were performed using the CANNY program. After the test results became available, the mathematical model was improved using an approach based on a displacement-controlled analysis. Basically, the same mathematical model was used as in pre-test analyses, except that the values of some of the parameters were changed. The OpenSees program was employed. Fair agreement between the test and numerical results was obtained. The results prove that relatively simple mathematical models are able to adequately simulate the detailed seismic response of reinforced concrete frame structures to a known ground motion, provided that the input parameters are properly determined. Figure 1. The elevation, the plan and the typical reinforcement of the SPEAR building: (a) the elevation and the plan view of the SPEAR building; and (b) typical reinforcement in beams and columns.Figure 10. Top displacements at CM and torsional rotations obtained with the post-test model and test results.obtained by displacement-controlled analysis (Figure 9), time-histories of the top displacements and rotations at CM (Figure 10), base-shear time-histories (Figure 11), envelopes of storey drifts at CM and at the column at the flexible corner C2 (Figure 12), storey drifts for column C2 plotted in the X -Y plane (Figure 13), and moment-rotation relationship for column C2 in the 2nd storey ( Figure 14). In the later case, the cumulative history for both 0.15 and 0.20g tests are plotted in the same diagram. More data, including the input file for the OpenSees program and detailed results for the described model and some other slightly different models, are provided in the post-test report [19]. A fair correlation can be observed between all of the computed and measured results. The results obtained by displacement-controlled analysis (Figure 9) demonstrate that the global strength and the global energy dissipation capacity of the post-test mode were modelled adequately, whereas both quantities were significantly overestimated in the pre-test model. The waveforms for the global quantities (top displacements and rotations, as well as base shears and torsional moments) correspond reasonably well in all cases (Figures 10 and 11). As expected, somewhat larger discrepancies occur in the case of more local quantities like storey drifts. However, the model correctly Figure 11. Base shears obtained with the post-test model and test results.F...

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