NEESR-CR: Post-Tensioned Coupled Shear Wall Systems

该奖项是NSF 09-524项目征集“小乔治·E·布朗地震工程模拟网络(NEES)研究(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(分奖)和利哈伊大学(分奖)。该项目将利用利哈伊大学的NEES设备场地。该奖项旨在研究地震区新结构体系的可行性，即抗震钢筋混凝土(RC)双肢剪力墙体系，其中采用广泛使用的无粘结后张拉(PT)RC楼板施工方法来连接(即连接)梁，以发展墙墩之间的耦合力。研究的目标是开发一种能提供显著的性能、施工和经济效益，并且在严重地震中几乎不会造成破坏的连体墙体系，而不是目前使用的斜交配筋连梁剪力墙体系。智力价值：这项研究的主要智力价值是研究了一种新型的、更实用的RC连体建筑墙体体系，与传统体系相比，它具有显著的性能和经济效益。在目前的建筑中，典型的连梁很难施工(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经历相当大的破坏。相比之下，新体系连梁的主筋由一根无粘结的PT筋组成，大大简化了施工。这一系统代表着一项重大的创新和变革，但它可以通过利用现有的和广泛使用的技术来实现。连梁的变形主要以末端空隙的形式出现，由于结构在大地震中发生横向位移，因此造成的破坏很小。地震发生后，PT筋提供了一种恢复力，可以弥合缝隙并将结构拉回其未变形的垂直位置。在地震区使用这些结构的唯一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，将进行大型物理实验室试验和多层连体墙体结构的计算机模拟相结合。实验室标本将包括两个原型系统的前三层、支撑板和基础，代表结构的最关键区域。结构的其他(不那么关键的)区域将在计算机中模拟，从而形成一个混合的物理-计算研究平台。将使用多个三维数字图像相关传感器监测实验室结构的变形，由此产生的近全场数据将通知其他项目区。最终，这些信息将导致为新系统开发经过验证的设计程序和建模/预测工具。广泛的影响：RC连体墙建筑结构在美国很常见。该研究将为社会提供直接的服务，追求新型连体墙体系的实际采用，从而提高施工经济性，减轻未来的地震损失。执业工程师将参加咨询小组，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。将多传感器数字图像相关技术应用于建筑结构评估是该工作的另一个创新方面，有助于在其他类似的研究项目中采用该技术。研究团队包括来自以本科生为主的机构(德克萨斯大学泰勒分校)的教职员工和学生，该大学设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该项目的影响。研究人员还将利用该项目通过K-12课堂演示和远程呈现会议来教育未来的工程师。传播、外联和技术转让活动将利用NEEShub的资源。该项目的数据将被存档，并通过NEES数据库向公众提供。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).