梁桥非线性随机地震响应的概率特性

为了分析随机地震作用下桥梁结构非线性响应的概率特性,采用Monte-Carlo数值模拟的方法,并利用弹塑性纤维梁柱单元模型模拟梁单元的非线性行为,对连续梁桥在不同地震峰值加速度作用下的非线性位移及内力时程响应进行了研究.得到了:墩顶位移非线性包络响应服从对数正态分布;桥墩轴力非线性包络响应的概率分布介于对数正态分布和极值I型分布之间;墩底剪力和弯矩非线性包络响应近似服从正态分布;墩底曲率非线性包络反应服从对数正态分布.研究表明:在相同场地条件下,地震峰值加速度的变化不影响结构非线性响应的分布类型,但对非线性响应的变异性影响较大.

Probability character istics of non-linear random seismic responses on continuous girder bridges

Based on Mo nte-Carlo simulat ion metho d, the pro bability characterist ics of non-l inear seismic response o f co nt inuous g ir der bridges, w ith st ructural randomicity and gro und mo tions randomicity being co nsidered, w ere studied. The elast ic-plast ic behavior of RC g ir der-co lumn element w as mo deled by f iber elast ic-plast ic element . Results show that log no rmal dist ribut ion can be used to model no n-linear displacement s at the top of piers and no n-linear curvature at the bo ttom of piers, that lognormal or Gumbel dist ribut ion can be used to model non-l inear ax ial fo rces o f piers, and that normal dist ribut ion can be used to model non-linear shear for ces and moment s at the bot tom o f piers. It can al so be seen f rom the resul ts that variance o f peak seismic accelerat ion does not affect the dist ribut ion types o f non-linear responses, but does affect the variability of non-linear r esponses.