Report - PEER - University of California, Berkeley

15001000500Shear [kN]0-8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 8.0-500-1000(a)Figure 2. R/C structure tested at ELSA: (a) Infilled frame configuration;(b) Bare frame 1 st storey shear-drift diagrams.Before the final cyclic collapse test, two additional pseudo-dynamic tests werecarried out: one with infill panels uniformly distributed along the height (see Fig. 2a)and another one with infills at the all but the ground storey. The final cyclic test onthe bare frame was performed with imposed top displacement and inverted triangularforce distribution. Fig. 2b shows the first storey shear-drift diagrams for the tests onthe bare frame structure.4.2 Assessment and Re-Design/Retrofit of Existing RC Frame StructuresA series of pseudo-dynamic tests on two full-scale models of a 4-storey R/C frame(Fig. 3a) representative of existing structures designed without specific seismicresisting characteristics (common practice of 40~50 years ago in South Europeancountries) were carried out at ELSA. Four testing campaigns were performed aimingat: (1) vulnerability assessment of a bare frame; (2) assessment of a selective retrofitsolution; (3) earthquake assessment of an identical frame with infill masonry walls;(4) assessment of shotcrete retrofitting of the infill panels.Contrarily to the strategy adopted in the tests described in Section 4.1, whichaimed at the verification of serviceability and life-safety limit-states and check of theultimate capacity, the tests on the model representing existing structures were focusedon the behavior and performance for input motions corresponding to the designactions of new structures as well as on the assessment of their ultimate capacity.Therefore, an input motion corresponding to a 475 yrp was adopted for the first teston the bare frame. The second test aimed at reaching ultimate capacity of the framesand was carried out with an input motion intensity corresponding to 975 yrp. The testson the retrofitted structure and on the infilled frame structure adopted the same inputintensities in order to allow for direct comparison with the original configuration. Asubsequent PSD test with an intensity corresponding to 2000 yrp was carried out.Illustrative results are given in Fig. 3b, whereas a detailed analysis of the test resultscan be found elsewhere (Pinto, 2002).-1500Drift [%](b)287