近断层强震作用下高层结构抗震随机分析和减震优化设计

Currently, the seismic performance analysis and vibration-reduction design of engineering structures subjected to near-fault strong ground motions are the cutting-edge and important research topics in the field of earthquake engineering. This project focuses on studying and solving the problems of modeling technique, law interpretation and design method for the stochastic seismic analysis and vibration-reduction design optimization of tall building structures under near-fault strong motions. Firstly, considering the orientation of the strongest pulse, a parameterized stochastic model of near-fault pulse-like ground motions is established, and one-dimensional or two-dimensional impulsive ground motion time histories with both the intensity and frequency nonstationarity are synthesized. Subsequently, the probability density evolution method for performing accurately and efficiently the random vibration and reliability analysis of nonlinear large-scale structures is developed. Meanwhile, the influence mechanism of stochastic dynamic response and damage failure probability of tall seismic buildings under near-fault strong earthquake action is investigated. Finally, the propagation regularity and influence factors of uncertainty of seismic responses of vibration-reduction tall buildings with base isolators, energy-dissipated dampers, and metamaterials subjected to the stochastic near-fault ground motions are revealed. The simultaneous optimization model for dampers layout and sizing and the decoupled probabilistic optimal design formulation are proposed, respectively. Moreover, a new optimization algorithm with good robustness and convergence as well as high efficiency is devised, and the optimal design result of vibration-reduction structure is achieved. As a critical link to investigate the engineering characteristics and structural effects of near-fault ground motions, this project provides a theoretical foundation for the realization of performance-based seismic design of buildings at the strong earthquake area.

近断层强地震动作用下工程结构抗震性能分析与减震设计是当前地震工程研究的前沿重要课题。本项目旨在研究解决近断层强震作用下高层建筑结构抗震随机分析和减震优化设计的建模技术、规律阐释与设计方法问题。首先，考虑最强脉冲方向，构建近断层脉冲型地震动的随机参数化模型，并合成强度和频率非平稳的一维/二维脉冲型地震动时程。其次，发展准确、高效地进行大型非线性结构随机振动与可靠度分析的概率密度演化方法，探究近断层强震作用下高层抗震结构随机动力响应和破坏失效概率的影响机理。最后，揭示近断层随机地震动作用下高层建筑基础隔震、阻尼消能和超材料减震结构地震响应的不确定性传播机制和影响因素，提出阻尼器布局与尺寸同步优化模型和解耦的概率优化设计列式，建立稳健、收敛的高效率优化新算法，并获得优化的减震结构设计方案。本项目是近断层地震动工程特性和结构效应研究的关键环节，可为实现强震区基于性能的建筑抗震设计提供理论基础。

近年来，近断层地震动工程特性及其作用下结构的随机抗震分析和减震优化设计成为地震工程学界关注和重视的研究课题。瞄准学科前沿和工程抗震减震需求，项目建立了一种新的功率谱模型以拟合近断层地震动的平均功率谱，构建了近断层脉冲型地震动合成的时频非平稳随机参数化模型。引入概率密度演化方法，并在广义概率密度演化方程施加吸收边界条件，高效地计算了非线性高层建筑结构的动力可靠度，考察了断层距和速度脉冲发生时刻对动力可靠度的显著影响。从非线性动力学理论中多重分形的新视角出发，揭示了近断层地震动的多标度行为和不规则性，提出了一种适用于地震动时程和结构地震响应的EMD-ELM多步预测新方法。而且，引入离散控制论提出了结构地震动力响应分析的数值阻尼可控的显式时程积分新算法，获得了随机地震激励下弹性薄板结构平稳/非平稳随机振动响应的精确基准解。提出了适用于一般结构系统地震响应量纲分析的具有明确物理意义的内禀长度尺度和时间尺度，建立了单自由度体系和非均匀刚度分布弯剪梁的自相似反应谱，有助于建筑结构的地震响应分析和抗震设计。发展了结构应力约束拓扑优化的IGA-SIMP方法，实现了几何精确建模、结构分析和优化设计的紧密结合。最后，提出了随机脉冲型地震动激励下高层建筑结构粘滞阻尼器的布局优化设计方法，阻尼器的优化布局明显减小了近断层随机强震作用下滞回高层框架建筑的平均最大层间位移角和楼层加速度，保障了高层建筑结构的地震安全。. 发表国际期刊SCI论文16篇，国内期刊论文8篇；相关成果荣获2017年国家科技进步奖二等奖；组织了6个国内外学术会议的专题研讨会，做大会报告和邀请报告5次；培养毕业的博士生2人、硕士生5人。