﻿ 体外预应力混凝土风力发电塔地震易损性分析
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 同济大学学报(自然科学版)  2018, Vol. 46 Issue (11): 1501-1507.  DOI: 10.11908/j.issn.0253-374x.2018.11.005 0

### 引用本文

CAO Yuqi, YANG Rongchang, LIU Huiqun, SHU Zhan. Seismic Fragility Analysis for External Prestressed Concrete Wind Tower[J]. Journal of Tongji University (Natural Science), 2018, 46(11): 1501-1507. DOI: 10.11908/j.issn.0253-374x.2018.11.005

### 文章历史

1. 同济大学 土木工程学院，上海 200092;
2. 同济大学建筑设计研究院(集团)有限公司，上海 200092

Seismic Fragility Analysis for External Prestressed Concrete Wind Tower
CAO Yuqi 1, YANG Rongchang 2, LIU Huiqun 2, SHU Zhan 1
1. College of Civil Engineering, Tongji University, Shanghai 200092, China;
2. Tongji Architectural Design (Group) Co., Ltd., Shanghai 200092, China
Abstract: The nonlinear analytical model of an external prestressed concrete wind tower was developed based on fiber beam-column element. Four damage states were defined based on the results obtained from pushover analysis. Twenty recorded ground motions were selected as the basis of incremental dynamic analysis. The peak ground acceleration and the horizontal displacement ratio were chosen as the intensity measure and the structural seismic demand parameter, respectively. Nonlinear incremental dynamic analysis was then performed and the probabilistic model of seismic demand was built through regression analysis based on lognormal assumptions. Subsequently, the fragility analyses were produced. The seismic fragility of the tower was evaluated, proving that the wind tower meets the requirements of 7-degree seismic fortification intensity. For 8-degree earthquakes, however, the probabilities of serious or complete damage significantly increase, according to the proposed analyses.
Key words: wind tower    seismic fragility    pushover analysis    incremental dynamic analysis

1 体外预应力混凝土风力发电塔设计

 图 1 体外预应力混凝土风力发电塔示意图 Fig.1 Diagram of external prestressed concrete wind tower

2 有限元模型

 图 2 钢绞线与混凝土塔筒相互作用建模示意图 Fig.2 Diagram of strand-tower interaction modelling

 图 3 Steel02本构与新定义本构对比 Fig.3 Comparison between original constitutive model and custom one
 图 4 体外预应力混凝土风力发电塔三维有限元模型(单位：mm) Fig.4 Three-dimensional finite element model of external prestressed concrete wind tower (unit: mm)

3 地震动的选取

 图 5 所选地震记录的平均反应谱 Fig.5 Mean response spectra of the selected input ground motions

4 结构增量动力分析 4.1 地震动强度参数的确定

4.2 结构需求参数的选取

 图 6 pushover分析得到的荷载位移曲线 Fig.6 Load-displacement curve obtained from pushover analysis

4.3 IDA

 图 7 IDA曲线 Fig.7 IDA curves
5 易损性分析 5.1 概率地震需求模型

 $F\left( y \right) = {P_{\text{f}}}\left[ {{L_{\text{s}}}\left| {{I_{\text{M}}} = y} \right.} \right] = P\left[ {C \leqslant D\left| {{I_{\text{M}}} = y} \right.} \right]$ (1)

 ${P_{\text{f}}} = \mathit{\Phi }\left( {\frac{{\ln {S_D} - \ln {S_C}}}{{\sqrt {\beta _{D|{I_{\text{M}}}}^2 + \beta _C^2} }}} \right)$ (2)

 ${S_D} = aI_{\text{M}}^b$ (3)

 $\ln {S_D} = \ln a + b\ln {I_{\text{M}}}$ (4)

5.2 概率地震需求分析结果

 图 8 地震需求参数拟合 Fig.8 Regression analysis of seismic demand parameter

 $\ln \frac{\mathit{\Delta }}{H} = 1.054\ln {I_{\text{M}}} - 4.354$ (5)
5.3 体外预应力混凝土风力发电塔易损性曲线

 ${P_{\text{f}}} = \mathit{\Phi }\left( {\frac{{1.054\ln {I_{\text{M}}} - 4.354 - \ln {S_C}}}{{\sqrt {\beta _{D{\text{|}}{I_{\text{M}}}}^2 + \beta _C^2} }}} \right)$ (6)

SC为损伤指标的均值，详见表 6中水平位移角限值.为简化计算，根据HAZUS99[12]，当结构地震易损性曲线以峰值地面加速度为自变量时，${\sqrt {\beta _{D{\text{|}}{I_{\text{M}}}}^2 + \beta _C^2} }$取0.5.

 图 9 体外预应力混凝土风力发电塔易损性曲线 Fig.9 Fragility curves of external prestressed concrete wind tower at all damage states

6 结论

(1) 体外预应力混凝土风力发电塔可采用纤维梁柱单元进行有限元模拟.相关建模技术可供同类结构整体分析参考.

(2) 通过pushover分析得到了以水平位移角为指标的4个体外预应力混凝土风力发电塔的损伤限值，分别为：完好1/375、轻微损伤1/280、中等损伤1/140、严重损伤1/90.

(3) 体外预应力混凝土风力发电塔可以满足7度设防区抗震设防要求，但在8度罕遇地震下，混凝土风力发电塔发生轻微损伤、中等损伤、严重损伤及完全损伤的概率分别为89%、74%、25%、5%.因混凝土风力发电塔的结构自重大，所受的地震作用大，建议8度及8度以上抗震设防区应谨慎使用.

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