EFFECT EVALUATION ON ENERGY-DISSIPATED RETROFIT OF REINFORCED CONCRETE FRAME STRUCTURE

摘要

In design of seismic retrofit,it is a key point for designers to accurately evaluate or learn about the seismic performances of post-retrofit structure.Thus research and discussion on effect evaluation were conducted for reinforced concrete(RC)frame structure retrofitted by using energy dissipation devices.Several performance-based criteria for retrofit evaluation were presented,which include different indicators of strength,deformation,ductility,energy,and damage,etc.Since energy dissipation devices were later-added components for the original structure,evaluation of the energy-dissipated retrofit structure should be conducted including the seismic performance assessment of post-retrofit structure and the impact assessment of additional energy dissipation components to the original structure,and therefore the main contents of assessment process for RC frame structure retrofitted by using energy dissipation devices incorporate analysis of damping effect,checking of elasto-plastic deformation,examination of seismic design details,and assessment of supplemental energy dissipation components' influences.Based on performance-based design concept,the expected performance objectives of energy-dissipated retrofit structure was preliminarily established,and the inter-storey drift of RC frame structure corresponding to different damage state were presented.Some issues about the reducing grade of seismic design details and ductility requirements in energy-dissipated structure were discussed according to current seismic design codes(i.e.Code for seismic design of buildings,Technical specification for seismic energy dissipation of buildings,etc.),which were(1)as the basis of the reduction of seismic design grade,the decreased seismic influence coefficient can't comprehensively reflect the practical effect of energy-dissipated retrofit structure,and(2)the reducing degree of seismic design grade of structure can't be quantified associated with the seismic influence coefficient.In the end,the value range of story drift rotation and shear force in RC frame structure associated with different reducing grades were recommended.