山区多层接地消能减震异形柱框架结构减震效果研究

STUDY OF SEISMIC MITIGATION EFFECT OF VISCOELASTIC FRAME STRUCTURE WITH SPECIAL-SHAPED COLUMNS CONNECTED WITH GROUND BY MULTIPLE-FLOOR IN MOUNTAIN REGION

针对山区多层接地消能减震异形柱框架结构,研究土体刚度、陡坎高度、陡坎下方掉层跨数对结构地震反应和减震效果的影响。分析表明:1)多层接地结构的自振频率随着土体软度的增大而变小,随着陡坎高度的增大而增大,随着陡坎下掉层跨数的增大而减小,但陡坎高度增大到一定程度后,会降低结构的高阶频率;2)多层接地结构的层位移随着土体软度的增大而变小,地基土刚度对结构层间位移、层间剪力和加速度反应的影响与地震动输入密切相关,当地震动输入的高频含量较少时,土体越软,地震反应越大;当地震波输入的高频含量较多时,在特软土情况下地震反应有可能减小;3)无控结构的地震反应受陡坎高度和掉层跨数的影响规律与地震动输入相关,而受控结构则受地震动的影响较小;且陡坎高度和掉层跨数对结构陡坎下方楼层的层间反应影响较大,而对陡坎上方楼层影响较小;4)多层接地减震结构的减震效果不仅与场地条件相关,还与地震动输入密切相关,应根据场地条件和地震分组情况合理选择阻尼器的数量和参数,才能达到较好的减震效果。

After discussing the seismic mitigation effect of soil stiffness , scarp height , and number of spans under the scarp on viscoelastic frame structure with special-shaped cloumns connected with ground by multiple-floor, the conclusions were as follows:1) The natural vibration frequency of structure decreased with the soil stiffness decrease , increased with the scarp height increase , and decreased with the spans under the scarp increase .But when the scarp height increases to a certain extent , the higher order frequency would be reduced .2 ) The soil stiffness effect on structure was related to the inputting of seismic motion .When the inputting wave contained less high frequency , the seismic responses might increase with the soil stiffness decrease .When the inputting wave cantained more high frequency, the seismic responses might be reduced on softer soil ground .3)The effect of scarp height and number of spans under the scarp on uncontrolled structure was related to the inputting of seismic motion , while on controlled structure it had less relation to the inputting of seismic motion .And the responses of floors under the scarp had greater impact than floors above when the scarp height and number of spans under the scarp were changed .4 ) The ground and inputting wave would both affect the control efficiency of viscoelastic structure on scarp .The ground condition and earthquake group of the site must be both taken account seriously when designing the damping device .