Collaborative Research: Testing and Analyses of Nonrectangular Walls Under Multi-Directional Loads

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Collaborative Research: Testing and Analyses of Nonrectangular Walls Under Multi- Directional Loads -- CMS 0324504PI: Cathy French, University of MinnesotaThis project represents a collaborative analytical, experimental and educational effort to investigate the behavior of nonrectangular structural walls subjected to the effects of multidirectional loading. Nonrectangular structural walls are often used to resist lateral loads and limit deformations in structural systems located in regions of moderate and high seismicity. Although such wall systems are intended to resist the lateral forces along the orthogonal axes of the building, past research has been limited to unidirectional studies of these systems due to limitations in experimental capabilities, as such the numerical models developed to describe their behavior have been calibrated to this limited data. The proposed project employs one of the first applications of an NSF George E. Brown, Jr., Network for Earthquake Engineering Simulation (NEES) large-scale testing facility, the Multi-Axial Subassemblage Testing (MAST) System at the University of Minnesota, to achieve the multidirectional testing requirements. This facility is ideal for the investigation as it is capable of six-degree-of-freedom (6-DOF) control including the ability to specify moment to shear profiles about each orthogonal axis to simulate the distribution of lateral forces applied to the wall system. It is anticipated that multidirectional loads will have a significant impact on the behavior of these nonrectangular wall systems as they are intended to resist lateral forces and limit deformations along the orthogonal axes of the building. The collaborative team of researchers from the University of Minnesota, Iowa State University, University of Puerto Rico at Mayaguez and The Nakaki Bashaw Group, Inc., a consulting firm in Irvine, California, bring combined strengths and resources in experimentation, analysis, design practice and education, all of which are essential components of the proposed investigation. All collaborative researchers will remotely participate in the experimentation including the operation of the test which will reside with Iowa State University. Intellectual Merit: This project builds on the combined strengths of the collaborative research team and newly available experimental capabilities to investigate a critical structural element for seismic regions, nonrectangular structural walls. The analytical and experimental studies developed in this project are expected to lead to improved understanding of the behavior, analysis techniques, and design of nonrectangular wall systems. The project will also recommend appropriate modifications to the design and detailing of nonrectangular wall elements suggested in the current building codes. Broader Impact: The project has a significant educational component through plans to incorporate the testing and simulation into the curriculum at the three collaborative universities including the participation of underrepresented groups. The involvement of the practicing engineer from the beginning of the project, who along with the Principal Investigator is involved in the development of the American Concrete Institute Building Code, ensures that the appropriate research findings may be translated directly into practice with improved detailing recommendations for nonrectangular structural walls. As such, this project will improve the nation's infrastructure in seismic regions. It is also anticipated that the results of this project will lead to valuable information for future remote users of the MAST system. This information will include documentation of any observed deformations of the reaction wall and crosshead, as well as the ability of the system to function under mixed mode control with large applied forces. The performance and userability evaluations of the remote participant capabilities within the MAST are intended to lead to an improved system for remote participation. The Co-PIs have a vested interest within this project to actively evaluate these capabilities as they are essential to their participation in this project. It is intended that the research data be made available to the research community through the NSF, George E. Brown Jr., NEES National Data Repository. Any hardware or instrumentation purchased at the University of Minnesota through this project will be available to future users of the MAST facility.