Report - PEER - University of California, Berkeley

Calculated and measured responses, in terms of base shear and first story drift angles,for M3 model and for the M8.3 artificial ground motion are presented in Fig. 8. It isapparent that a good agreement was reached in the base shear response, but somedifferences were noted in the drift response. Evidently, such difference indicates theneed to improve the nonlinear modeling of complex confined masonry, with emphasison better capturing the effect of confinement, especially at large drift angles, and ofperpendicular walls.Base shear, kNBase shear, kN3002001000-100-200-3003002001000-100-200-300-0.6 -0.4 -0.2 0 0.2 0.4 0.6-0.6 -0.4 -0.2 0 0.2 0.4 0.6Drift, %Base shear, kNDrift angle, %Base shear, kNDrift angle, %3001500-150-3000.517 18 19 20 21 22 23 240.250-0.25300150-150-300-0.500.50.250-0.25-0.517 18 19 20 21 22 23 2417 18 19 20 21 22 23 24Time, sFigure 8. Calculated (top) and measured responses of M3.5. CONCLUDING REMARKSTo assess the seismic performance of typical Mexican confined masonry houses, aseries of shaking table tests are underway. A series of recorded and artificial groundmotions, consistent with the seismic hazard of the Mexican Pacific coast, were usedas input. Engineering design parameters have been developed and have beencompared to experimental results. Aimed at predicting the nonlinear response ofmasonry structures, a simple analytical model has been developed from static cyclictests. With this model, the response of the models tested at the shaking table wascalculated. Comparisons of the measured and calculated responses indicated goodagreements in base shear, but some differences in drift. This difference indicates theneed to improve the nonlinear modeling of complex confined masonry, with emphasison capturing the rate effect on stiffness decay, as well as the effect of confinementand of perpendicular walls.ACKNOWLEDGEMENTSResearch on the shaking table tests were supported by the Consejo Nacional deCiencia y Tecnología (CONACYT-Mexico).243