NEESR-CR: Post-Tensioned Coupled Shear Wall Systems

该奖项是NSF 09-524项目招标的结果，“小乔治·e·布朗地震工程模拟（NEES）研究网络（NEESR）”竞赛的结果，包括圣母大学（牵头机构）、德克萨斯大学泰勒分校（次级奖项）和里海大学（次级奖项）。该项目将利用利哈伊大学的NEES设备站点。该奖项调查了地震区新结构系统的可行性，即抗震钢筋混凝土（RC）耦合剪力墙系统，其中广泛使用的无粘结后张拉（PT） RC楼板施工方法适用于耦合（即链接）梁，以发展墙墩之间的耦合力。研究目标是开发一种耦合墙系统，该系统具有显著的性能，结构和经济效益，并且在严重地震中承受的破坏很小，超过目前使用的剪力墙与对角增强耦合梁的耦合。智力价值：本研究的主要智力价值是研究一种新的、更实用的抗震钢筋混凝土耦合建筑墙体体系，其性能和经济效益优于传统体系。在目前的建筑中，典型的连接梁很难建造（它们需要大量的钢筋以复杂的几何形状排列），并且在地震荷载下可能会遭受相当大的破坏。相比之下，新系统耦合梁中的主筋由单个无粘结PT肌腱组成，大大简化了施工。该系统代表了一项重大的创新和转变，但可以通过利用现有的和广泛使用的技术来实现。耦合梁的变形主要以两端开缝的形式出现，当结构在大地震时发生横向位移时，造成的破坏很小。地震后，PT肌腱提供了一种恢复力，使裂缝闭合，并将结构拉回其未变形的垂直位置。在震区使用这些结构的一个主要障碍是缺乏经过实验验证的设计方法、施工程序和数值模拟模型。为了填补这一知识空白，将进行大规模的物理实验室实验，并结合多层耦合墙结构的计算机模拟。实验室样本将包括前三层，分支板和两个原型系统的基础，代表了结构的最关键区域。其他（不太关键的）结构区域将在计算机中进行模拟，从而形成一个混合物理计算研究平台。实验室结构的变形将使用多个三维数字图像相关传感器进行监测，由此产生的近全场数据将通知其他项目区域。最终，这些信息将导致新系统的验证设计程序和建模/预测工具的开发。更广泛的影响：RC耦合墙建筑结构在美国很常见。本研究将为社会提供直接的服务，寻求一种新型的耦合墙系统的实际应用，从而提高建筑经济性，减少未来的地震损失。实践工程师将参加一个咨询小组，与相关专业组织的互动将有助于将结果迅速传播给最终用户。在建筑结构评估中实现多传感器数字图像相关是工作的另一个创新方面，可以帮助在其他类似研究项目中采用该技术。研究团队包括来自主要的本科机构（德克萨斯大学泰勒分校）的教师和学生，其中有一个新的和不断发展的土木工程系，其研究和教育活动将受到这个项目的影响。研究人员还将利用该项目通过K-12课堂演示和远程呈现课程来培养未来的工程师。传播、外联和技术转让活动将利用NEEShub的资源。该项目的数据将存档，并通过NEES数据储存库向公众提供。该奖项是国家减少地震灾害计划（NEHRP）的一部分。

This award is an outcome of the NSF 09-524 program solicitation, "George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes the University of Notre Dame (lead institution), the University of Texas at Tyler (subaward), and Lehigh University (subaward). This project will utilize the NEES equipment site at Lehigh University. This award investigates the feasibility of a new structural system for seismic regions, i.e., a seismic-resistant reinforced concrete (RC) coupled shear wall system where the widely-used, unbonded post-tensioned (PT) RC floor slab construction method is adapted for coupling (i.e., link) beams to develop coupling forces between the wall piers. The research objective is to develop a coupled wall system that provides significant performance, construction, and economic benefits, and that sustains little damage during a severe earthquake, over currently used shear walls coupled with diagonally reinforced coupling beams. Intellectual Merit: The primary intellectual merit of the research is the investigation of a new and more practical type of earthquake-resistant RC coupled building wall system with significant performance and economic benefits over conventional systems. Typical coupling beams in current construction are difficult to construct (they require large amounts of reinforcing steel arranged in complex geometries) and can experience considerable damage under seismic loading. In comparison, the primary reinforcement in the coupling beams of the new system consists of a single unbonded PT tendon, greatly simplifying construction. This system represents a significant innovation and transformation, but one that can be realistically achieved by utilizing an existing and widely-used technology. The deformations in the coupling beams occur primarily in the form of gap opening at the ends, resulting in little damage as the structure displaces laterally during a large earthquake. After the earthquake, the PT tendons provide a restoring force that closes the gaps and pulls the structure back toward its undeformed, plumb position. The single major barrier to the use of these structures in seismic regions is the lack of experimentally-validated design methods, construction procedures, and numerical simulation models. To fill this knowledge gap, large-scale physical laboratory experiments integrated with computer simulations of multi-story coupled wall structures will be conducted. The laboratory specimens will include the first three floors, tributary slabs, and foundations of two prototype systems, representing the most critical regions of the structures. The other (less critical) regions of the structures will be simulated in the computer resulting in a hybrid physical-computational research platform. Deformations of the laboratory structures will be monitored using multiple, three-dimensional, digital image correlation sensors, and the resulting near-full-field data will inform the other project areas. Ultimately, this information will lead to the development of validated design procedures and modeling/prediction tools for the new system.Broader Impacts: RC coupled wall building structures are common in the United States. The research will provide direct service to society by pursuing the practical adoption of a new type of coupled wall system, thereby improving construction economy and mitigating future earthquake losses. Practicing engineers will participate in an advisory panel, and interactions with relevant professional organizations will facilitate rapid dissemination of the results to end users. Implementation of multiple-sensor digital image correlation for building structural evaluation is another innovative aspect of the work that can aid in adoption of this technology in other similar research programs. The research team includes faculty and students from a predominantly undergraduate institution (University of Texas at Tyler) with a new and growing civil engineering department whose research and educational activities will be impacted by this project. The researchers will also use the project to educate future engineers through K-12 classroom presentations and telepresence sessions. The dissemination, outreach, and technology transfer activities will utilize NEEShub resources. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).