ABSTRACT
The most significant recent advances in seismic engineering have been the development of a range of variable isolator devices. These include various combinations of simple rubber sheets, steel plates, lead extrusion elements and steel torsional and flexural curved beams. However all these devices cater for reducing the effect of horizontal ground motion on the structure. In the latest Northridge and Kobe earthquakes, it was evident the vertical component of a strong ground motion can have very damaging effects on reinforced and steel columns. This paper is proposing for the first time a vertical shock absorber that is backed up by experimental as well as analytical results which illustrate its functionality and performance in reducing the effect of vertical vibration on a structure. A review of vertical ground motion effects on building columns is given first, then testing of plain concrete samples under cyclic dynamic loading is presented. A two dimensional analysis of a frame structure with vertical elasto-plastic bearing is discussed and then a prototype of the new vertical shock absorber is introduced together with the testing and analysis work which its satisfactory performance.
