体外预应力混凝土风力发电塔地震易损性分析

Seismic Fragility Analysis for External Prestressed Concrete Wind Tower

摘要:

以体外预应力混凝土风力发电塔为研究对象，采用纤维梁柱单元，建立了非线性有限元分析模型.基于pushover分析结果定义了4个损伤状态限值.选取20条真实的地震动记录进行增量动力分析，分别以水平位移角和地面加速度峰值作为结构地震需求参数和地震动强度参数，基于对数正态分布假设回归分析建立了概率地震需求模型.形成了体外预应力混凝土风力发电塔的易损性曲线，并对发电塔地震易损性进行评估.结果表明：体外预应力混凝土风力发电塔可满足7度设防区抗震设防要求，而在8度罕遇地震下有一定概率发生严重或完全损伤.

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.