1、第四章 隔震結(jié)構(gòu)的分析令 第一節(jié) 正交阻尼結(jié)構(gòu)1 1.1 Equations of Motionss2 Mass Ratios Nominal FrequenciesAssume1.2 Definitions of Several Factors Nominal Damping Ratios b and s 31.3 Modal Analysis Characteristic Equation for the Frequencies Free Vibration Equations of Undamped System 4 Solutions of Characteristic Equatio

2、n Mode Shapes Approximation to first order in 5 Mode Coordinates q premultiplying by T Modal Equationswhere Modal Load Factor (振型參與因子) Li is given by6 Uncoupled Modal Equationsand modal damping ratio i is computed from7 Maximum DisplacementsApproximation to first order in 8 1.4 Base Shear Coefficien

3、t of Superstructure9第二節(jié) 非正交阻尼結(jié)構(gòu)2.1 Significance of off-diagonal damping terms10112.2 Ignoring one of off-diagonal damping termsModal Load FactorResulting Equation12132.3 Interstory Drift14(i) that contributed by the uncoupled first mode(ii) that from the uncoupled second modeThree Items15(iii) that

4、from the coupled term Relation with Response Spectrum1617I3SVI4SV18Constant Velocity Spectra注意：H()修正與我國規(guī)范的差異例如，H()可取19Ignore 2 and in the 3rd term20Kawashima-Aizawa FunctionR=0.33 when b=0.1R=1.80 when b=0.5Example212.3 Floor Acceleration22算例已知：隔震結(jié)構(gòu)重量為W，周期為2.5s，阻尼比5，=1/25，=1/2。按規(guī)范算得的隔震層位移為76cm，為減小位移在隔震層設(shè)置粘滯阻尼器，其阻尼比為50。求增設(shè)粘滯阻尼器后的隔震層位移、基底剪力和屋面加速度。解：(1)隔震層位移為23最大位移時的底部剪力為阻尼力最大剪力偽速度譜值按p22頁公式計算樓面加速度，結(jié)果如下：基底剪力屋面加速度2425參考文獻(xiàn)1. Naeim F and Kelly JM, “Design of seismic i