SEISMIC PERFORMANCE OF DUCTILE AND NOMINALLY DUCTILE REINFORCED-CONCRETE MOMENT-RESISTING FRAMES - I - EXPERIMENTAL-STUDY

This paper is the first of two companion papers on the evaluation of t he level of protection offered by ductile and nominally ductile reinfo rced concrete structures in Canada. In this paper, the seismic behavio ur of two half-scale reinforced concrete moment resisting frames is in vestigated by shake table tests. In the second paper, the experimental results obtained from the shake table tests are compared with the res ults generated from inelastic time-history dynamic analyses. Each fram e had two bays and two storeys with overall dimensions of 5 m in width and 3 m in height. The first structure was designed as a ductile fram e according to current Canadian standards; and the second structure in corporated only nominally ductile details. Two levels of intensity wer e retained for the historical ground motion used in the tests. The fir st level was representative of the design earthquake considered; the a mplitudes were doubled for the second intensity. The ductile structure performed well during both tests. The frame with nominal ductility pe rformed well during the first test, but was on the verge of collapse a fter the second test. Based on these experimental results, recommendat ions are presented to harmonize the seismic protection of ductile and nominally ductile reinforced concrete frames in Canada.