MARIANELA LAFUENTE, ENRIQUE CASTILLA AND CARLOS GENATIOS IMME, Universidad Central de Venezuela.
The main results of an analytical and experimental study are presented. Experimental evidence leads to recommendations for the analysis and design of structures .of confined or reinforced masonry walls subjected to seismic loads. Final conclusions do not support the procedure of taking advantage of the inelastic-behaviour of the material for seismic resistant design and suggest the exploration of other alternatives to obtain ductile mechanisms which allow stable energy dissipating hysteresis cycles. An analytical model has been developed for the non-linear behaviour of confined masonry walls subjected to lateral loads, taking into account cracking and several failure criteria. Equations are proposed for the evaluation of the resistance of confined masonry walls, depending on axial load and geometry. Design lateral drift limits are also recommended. An expression is proposed to establish an adequate overlapping length of vertical steel bars in reinforced masonry walls.