Research On Joints With Dampers Used In Seismic Strengthening Of Super-long Frame Structure

When the frame is long,it’s not possible to ignore the temperature effects.Expansion joints are usually used to reduce the temperature effects,yet the expansion joints of the structure may cause pounding effect.So it is useful to use dampers to absorb earthquake shock,thus reduce width of slot.This paper aims at the comparison of the structure with and without expansion joints,and with and without dampers in expansion joints,to get conclusions of the effects of setting expansion joints and dampers to seismic response.The detailed information are as follows:1、Analyze the three structures in the condition of temperature drop.The results are listed as stress and deformation trend of plates,and maximum axial force of specific beam,and maximum bending moment and bending deformation of specific column,and it shows that crack resistance in the three structures needs to be reinforced;the deformation in the top is more sufficient than in the bottom,so the region of maximum tensile stress increase in the edge,while in the centre,maximum tensile stress decrease after splitting;the dampers can decrease the stress caused by over-strain,yet increase stress in conditions of over-constraint.2、Define the additional damper of the third structure.Analyze the three structures in the condition of modality.The results are listed as modal shape and periods of first three steps.It shows that the second structure owns the longest period.What’s more,it is assignable to pay attention to torsion when the structure is too long.The split structure without dampers cannot avoid torsion and even collision,yet the split structure with dampers will not twist.3、Analyze the three structures in the condition of elastic earthquakes.After comparing the results of the three structures,the results shows that joints are better for decreasing peak acceleration and storey shear Y.The storey displacement does not change too much.The results of storey displacement in response spectrum and time-history analysis differ great.The storey shear X decrease overall,yet the storey displacement may decrease or increase.The dampers help decreasing the peak acceleration and storey displacement.The storey shear decrease much overall after using dampers,yet some may not decrease so much as dampers may make contribution to the relative drift thus increase the storey shear to some extent.4、Analyze the three structures in the condition of plastic earthquakes usingpushover analysis and elastic-plastic time-history analysis.According to pushover analysis,the equivalent damping ratio is 0.07 for X and 0.0976 for Y.Joints cannot make contribution to seismic response Y.The storey shear X decrease while the story drift increase after using joints.All seismic response decrease much after using dampers in joints.So dampers in joints make more contribution to decreasing seismic response under rare earthquakes than under frequent earthquakes.The usage of dampers in joints can be well used in super-long structure.