三维地震动作用下适用于高耸结构的地震动强度指标

烟囱、水塔和广播电视塔等高耸混凝土结构属于高柔的悬臂结构。现有的地震动强度指标多集中于一维或二维地震动作用下的建筑结构，而高耸混凝土结构对竖向地震极其敏感，有必要开展考虑竖向地震动作用的地震动强度指标研究。该文针对混凝土烟囱和水塔结构，提出了一种同时考虑高阶振型和周期延长效应的复合型地震动强度指标，并分别在三维远场地震动和近断层脉冲地震动输入条件下，对该指标的充分性和有效性进行分析和检验。通过和既有的15种地震动强度指标的有效性对比，发现该文提出的指标在三维条件下对这类结构具有较强的适用性。因此，该指标可作为评价高耸混凝土结构抗震性能的一个合理的指标。

AN EARTHQUAKE INTENSITY MEASURE FOR HIGH-RISE STRUCTURES UNDER THREE-DIMENSIONAL EARTHQUAKE GROUND MOTIONS

High-rise concrete structures are long and flexible cantilever structures which are commonly used as chimneys,water towers and TV towers.The existing earthquake intensity measures(IMs)mainly focus on building structures under one-dimensional or two-dimensional input ground motions,but high-rise concrete structures are sensitive to vertical ground motions.Based on a chimney and a water tower,it proposes a combined earthquake intensity measure which considers both the higher-mode effect and period elongation effect.The sufficiency and efficiency of the IM are investigated for three-dimensional far-field ground motions and near-fault ground motions with the pulse-like effect.A comparison is made among fifteen existing IMs,and the results indicate that the proposed IM is suitable for such kind of structures.Consequently,this IM is a promising intensity measure in the seismic assessment of high-rise structures under three-dimensional ground motions.