To investigate the seismic behaviors of frames in framewall structures (dual system)

which may be different from those of frame structures

two framewall structures were designed conforming to current Chinese design codes. One is a twentyfourstory building on the Zone of Fortification Intensity 8 (0.3g)

and the other is a thirtystory building on the Zone of Fortification Intensity 8 (0.2g). Then inelastic dynamic response analyses of the two structures were conducted with series of inputs of ground motions in a rare earthquake level. The seismic behaviors of the two structures were investigated preliminarily. It was found that the columns and beams of the frames in the framewall structures did not experienced yielding under strong earthquake

while coupled beams in walls were the major energydissipation elements with their postyielding plasticity. And the bases of some walls formed hinges as well. The reasons for the frames of dual system remained nonyielding states were analyzed and discussed from the aspects of their favorable loadcarrying state and strengthening measures for them in dual systems in Chinese design codes. A preliminary proposal was made that it may be feasible to loosen moderately some seismic fortification measures concerning the frame in the dual system with a height exceeding 60m on the Zone of Fortification Intensity 8.