2009 Volume 16 Issue 64 Pages 64_1-64_10
There are some differences in the steel structures from the view of seismic design and practice between U.S., and Japan. In Japan all columns and beams are the seismic elements in X and Y directions. In U.S. frames in the perimeter zone are only the seismic elements, and the columns inside the building are designed as the gravity columns which support only the weight of the building. In our previous research, it is clarified that such gravity columns can control story drift concentration during an earthquake. We need more study about the effect of damage control for beams and columns by the gravity columns. We will discuss about the seismic limit capacity of the moment resisting frames when the beams or the columns reach their plastic deformation capacities.