基于PBEE方法的RC高层建筑结构地震作用下性能评估关键问题研究

With the rapid development of economy in China, tall buildings have been widely constructed and distributed in the past decades. As earthquake frequently occurs in China, it is necessary and has significantly social meaning to reasonably evaluate the seismic performances of these tall buildings subjected to earthquake. This project focuses on seeking the solutions to key techniques in the seismic performance evaluation of reinforced concrete (RC) tall buildings based on a novel law of total probability used in performance-based earthquake engineering (PBEE), including the effect of ground motion (GM) frequency spectrums on the seismic performances, the effect of interaction between moment and shear force on the RC shear walls and the effect of coupling beams on coupled wall systems. To solve these key issues, the double-parameters GM indicator considering frequency spectrums and peak ground acceleration (PGA) is adopted to quantitatively present the effect of GM frequency spectrums on the fragility curve surface and collapse probability of RC tall building structures; in order to consider the impaction of the high mode, modal mass participating in the coefficient weighted to uniformly is used to select conditional period T* and GM spectrum shape parameter ε(T*) of conditional mean spectrums; the moment is equivalent to a force pair loading on the RC shear walls quasi-static cyclic test to study the effect of interaction between moment and shear force; developing nonlinearly analytical model of conventionally and diagonally reinforced coupling beams to couple the effect of coupling beams on coupled wall systems; meanwhile, machine learning algorithm is utilized to rationally choose the damage indicators of RC shear walls. Finally, quantify various uncertain parameters (e.g., uncertainties in GM inputs, structures, damages, and loss) and calculate the relevant probability and cumulative loss to assess the seismic performance of reinforced concrete tall buildings.

我国目前高层建筑大量涌现，合理评估高层建筑在遭受地震后的性能具有重要意义。本项目基于新的全概率PBEE方法对钢筋混凝土高层结构进行性能评估，重点解决其中的关键问题，包括地震动谱形特性对高层建筑结构性能的影响、弯矩与剪力耦合作用对剪力墙性能的影响、开洞后由于连梁作用引起的联肢剪力墙复杂非线性问题。针对以上问题分别提出：采用考虑地震动频谱成分和峰值加速度的双参数地震动指标；考虑高阶振型影响，按振型质量参与系数加权平均选择条件均值谱中的条件周期T*和地震动谱型参数ε(T*)，定量给出地震动谱形特性对高层建筑结构易损性曲面和结构倒塌率的影响；将弯矩等效成力偶的形式加载的剪力墙弯剪耦合低周往复试验；分别开发出普通配筋和对角斜筋连梁的非线性剪切滞回模型；采用机器学习方法筛选合理的剪力墙的损伤指标。最后，量化各种不确定性参数(地震动输入、结构、损伤和损失不确定性)，计算相关概率和累计损失。

本研究基于新的全概率PBEE方法对钢筋混凝土高层结构进行抗震性能评估，重点解决其中的关键难点问题，包括地震动谱形特性对高层建筑结构性能的影响、弯矩与剪力耦合作用对剪力墙性能的影响、开洞后由于连梁作用的联肢剪力墙复杂非线性分析模型。针对以上问题分别提出：1)考虑高阶振型影响，提出了一种考虑高阶振型影响的振型加权条件均值谱方法。该方法以振型参与质量系数作为权重，将各振型下的条件均值谱组合起来，通过分析并建议此方法推广用于高层工程结构作为目标谱；2)设计了新型弯矩与剪力耦合加载的剪力墙抗震性能试验，与传统拟静力试验相比，本次试验竖直方向加载通过两个作动器实现弯矩与水平剪力保持固定比例关系；3)提出了一种模拟联肢剪力墙结构体系非线性反应的数值分析模型，通过分析结果与试验结果的对比可知，新的分析模型能够较准确的预测联肢剪力墙体系在低周反复荷载下的非线性响应；4)基于机器学习的剪力墙损伤判别模型；5)最后采用全概率PBEE方法对RC高层结构进行了地震损失评估，并选择维修成本、维修时间及人员伤亡三种性能指标的评估结果进行分析。