Experimental Study On Seismic Performance Of An Innovative Resilient Rocking Column With Replaceable Steel Slit Dampers

An innovative resilient rocking(IRR)column with replaceable steel slit dampers was developed to achieve rapid restoration of structural functionality after earthquakes,which has emerged as an important issue facing the structural engineering profession over the last few decades.The IRR column,which can be prefabricated and easily assembled in-field,consists of several components,including a rocking column,several steel slit dampers,connection plates and high strength bolts.The load carrying mechanism was first described and the calculating method of the horizontal load carrying capacity was then proposed.Six full-scaled IRR columns,which were all designed based on “strong-column/weak-damper” philosophy,were manufactured and tested under pseudo-static cyclic loading to investigate the overall seismic performance and verify the design method.The primary test variables were the thickness of steel slit dampers,axial compression ratio and shear span ratio of the column.Test results showed that IRR columns exhibited quite satisfactory performance in terms of high strength and stiffness,excellent ductility,and stable hysteretic behavior.Plastic deformation was concentrated only in the steel slit dampers under large drift ratio while the other major components stayed nearly elastic,which was in consistent with the original design purpose.Hence,the columns could be easily repaired and the downtime of the structural functionality would be greatly reduced.Two of the IRR columns were repaired in situ after being loaded up to 3% chord rotation,and were subsequently loaded up to 5% chord rotation to study the seismic performance of the specimens after repair.The performance of the repaired specimens was nearly the same as their counterparts before repair,indicating that the replacement details were feasible.The horizontal load carrying capacity increased with the increase of the thickness of steel slit dampers and axial compressive load.The maximum horizontal load carrying capacity of the IRR column based on the proposed design method produced a reasonably conservative results compared with test result.