RAPID: Evaluation of Analytical Assessment Tools through Comparisons to Observed Seismic Performance in the January 2010 Haiti Earthquake

2010年1月12日，海地发生7.0级地震，严重破坏了首都太子港的几座现代工程建筑。这项研究项目将收集这些结构的观测性能的易腐烂数据，以便与地震评估程序中使用的基于分析的响应预测进行比较和校准。这项研究是学术界和产业界的合作，大学研究人员与地震工程咨询公司Rutherford and Chekene的专业人员一起工作。该项目依赖于与加拿大舍布鲁克大学的一名教员的密切合作，这名教员已经建立了联系，并对海地的实地情况有了第一手了解。这项研究的目标是：(1)对海地地震中一类结构的破坏情况进行编目和分类；(2)将破坏与结构系统、布局、设计和细节相关联；(3)评估当前评估中使用的分析技术和程序的有效性。预期的研究成果是一份记录以下内容的报告：(1)结构/场地说明；(2)设计信息；(3)震后状态记录；(4)分析技术和模型说明；(5)分析结果和比较；以及(6)方法评价。研究将涉及设计、现场条件和观察到的一小部分重要工程结构(学校、研究所、政府大楼)的损坏情况的文档，重点是钢筋混凝土结构。根据受损情况、现有的设计信息和可达性，已经确定了所有候选结构，均位于首都太子港。候选结构的抗震性能将主要通过研究小组和合作者在海地的现场目测获得。检查中将包括故障模式、损坏强度和模式以及剩余状态。现有的信息将被用来使用最先进的非线性动态分析技术来构建分析模型。将根据造成观测到的破坏所需的需求水平来估计地震危险程度。在此过程中，将对分析模型进行增量动力分析，以便将观测到的损伤映射到USGS抖动图提供的参考幅度。然后，可以使用美国常见的公认地震评估技术(线性、非线性、静态和动态)进行观测响应的预测，并将其与观测的实际性能进行比较。特别是，将评估结构模型产生类似行为模式、总体损害模式和适当评估决策的有效性。这些方法的有效性将通过将预测反应与实际结果进行比较而得出结论。将初步评估响应对各种参数的敏感度并进行模型校准。在可能的情况下，将对预测对不同变量的敏感性和不确定性进行估计。这项工作收集了在实际地震事件中建筑物性能的易腐烂信息，并有可能提供关于地震评估的关键步骤的信息，即模型校准。这项研究还扩展了关于钢筋混凝土结构在地震中的抗震性能的知识。这项研究的潜在影响是，通过改进的分析模型和评估技术以及改进的翻新评估，提高公共安全，更明智地作出与基础设施翻新和升级有关的决策。该项目提供的信息可供地震工程研究人员广泛使用。项目成果将通过行业合作伙伴参与专业团体和委员会的方式向专业人士提供。项目调查人员还将在2010年夏秋海地地震快速奖研讨会上介绍研究结果。

The magnitude 7.0 January 12, 2010, Haitian earthquake severely damaged several modern engineered buildings in the capital city of Port-au-Prince. This research project will gather perishable data on the observed performance of these structures for the purposes of comparison with, and calibration of, analytically-based response predictions used in seismic assessment procedures. The research is a partnership between academia and industry with university researchers working alongside professionals from the earthquake engineering consultant firm, Rutherford and Chekene. The project relies on close collaboration with a faculty member at the Université de Sherbrooke, Canada, who has established contacts and first-hand knowledge of the conditions on the ground in Haiti. The objectives of the research are to: (1) catalog and classify damage for a class of structures in the Haiti earthquake; (2) correlate damage to structural system, layout, design and detailing; and, (3) evaluate the efficacy of analytical techniques and procedures used in current assessment. The expected research outcome is a report documenting: (1) structure/site description; (2) design information; (3) documentation of post-earthquake state; (4) description of analytical techniques and model; (5) analytical results and comparisons; and (6) evaluation of the methods. The research will involve the documentation of the design, site conditions, and observed damage on a small set of important engineered structures (schools, institutes, government buildings), focusing on reinforced concrete construction. Candidate structures have been identified, all within the capital city of Port-au-Prince, on the basis of damage state, available design information, and accessibility. Seismic performance of the candidate structures will be obtained primarily from on-site visual inspection in Haiti by the research team and collaborators. Included in the inspection will be failure modes, damage intensity and patterns, and residual state. The available information will be used to construct analytical models using state-of-the-art techniques for nonlinear dynamic analysis. Seismic hazard levels will be estimated by indexing to the level of demand required to bring about the observed damage. In this process, the analytical models will be subjected to incremental dynamic analysis in order to map the observed damage to reference amplitudes available from USGS shake maps. Then, predictions of the observed response can be conducted using accepted seismic assessment techniques common in the U.S. (linear, nonlinear, static, and dynamic) and compared to the observed actual performance. In particular, the effectiveness of the structural models to produce similar behavior modes, overall patterns of damage, and appropriate assessment decisions will be evaluated. Conclusions on the efficacy of these methods will be drawn through comparisons of the predicted response to actual outcomes. Preliminary evaluation of the sensitivity of the response to various parameters and model calibration will be performed. Where possible, the sensitivity of the predictions to different variables and estimations of uncertainty will be made. This work gathers perishable information on building performance in actual seismic events and has the potential of providing information on a key step in seismic assessment, namely calibration of models. This research additionally extends knowledge on seismic performance of reinforced concrete structures in earthquakes. The potential impact of this research is increased public safety and more informed decision making pertaining to infrastructure retrofit and upgrading through improved analytical models and assessment techniques, as well as improved retrofit evaluations. The information provided by this project can be used widely by earthquake engineering researchers. Project results will be made available to the profession through the industry partners' participation in professional groups and committees. Project investigators will also present results of the study at a workshop for Haitian earthquake RAPID awards in summer or fall of 2010.