Journals Proceedings

Abstract

Most of current seismic design codes accept heavy damages to the building in case of large earthquakes, provided that the building is prevented against collapse. However, this acceptance leads to some unacceptable consequences in populated cities, like very great number of people who lose their residence or work place for very long time. To overcome these difficulties one approach is design of ‘repairable structures’ for buildings, by using the idea of ‘Deliberate Directing of Damage’ (DDD), which means guiding the damage to some pre-decided parts or elements of the structural system, so that other parts do not experience any plastic deformation. In this study the DDD idea has been employed for design of repairable steel buildings based on creation of building’s rocking motion possibility rather than its shear deformation, by using a central hinge support and circumferential energy dissipating columns at base level. Energy dissipation is done by a Multiple Trapezoidal Yielding Plate Energy Dissipating (MTYPED) device, installed at the bottom of the column, which creates a type of hysteretic behaviour in axial deformation of columns. By performing a set of finite elements analyses on MTYPED devices their initial stiffness as well as their yielding strength were obtained, and then they were modelled in a real size building by using nonlinear springs, and a series of nonlinear time history analysis were performed on both rocking building and the conventional building with the same geometry. Results show that the proposed rocking system equipped with MTYPED devices not only gives the building a longer natural period, leading to lower seismic demand, but also leads to remarkable energy dissipation capacity in the building structure at base level, and therefore, keeping the seismic drifts in elastic range in all stories of the building above the ground floor, so that the building structure does not need any major repair work after a large earthquake. This is while the conventional building suffers from heavy damage and needs to be demolished after an earthquake.