NEESR-SG: Seismic Behavior, Analysis and Design of Complex Wall Systems

University Of Washington, Seattle WA

Investigators

Abstract

SEISMIC BEHAVIOR, ANALYSIS AND DESIGN OF COMPLEX WALL SYSTEMS: PROJECT SUMMARY Reinforced concrete structural walls are used commonly as the primary lateral-load resisting system for new and retrofit construction. However, despite the heavy reliance on wall systems by practicing engineers, recent efforts to develop performance-based design methods have not yet begun to address structural walls. Today, engineers have few resources to consult regarding the simulation of wall response using practical linear and nonlinear numerical models or the prediction of wall damage (e.g., concrete crack width and concrete spalling) as a function of engineering demands (e.g., inter-story drift). In part, the inadequacy of available performance-based design tools for walls is a result of limitations in the available experimental data. Prior to the NEES initiative, experimental facilities were such that only simplified loading conditions, loading histories, boundary conditions, and geometries could be employed in the laboratory. Additionally, instrumentation was such that experimental data typically include wall displacements and end rotations, average strain measurements and a few analog images showing damage progression. Only a few existing experimental data characterize the response of walls with complex geometries or subjected to bi-directional load histories. None of these data sets include high-resolution strain fields for use in validating advanced simulation tools, nor do any of these data sets include highresolution digital images that can be used to quantify damage. No experimental investigations consider boundary conditions that simulate soil and foundation deformations. INTELLECTUAL MERIT The research proposed here will advance the understanding of, and simulation tools for, the seismic performance of slender walls through experimental and analytical investigations of wall systems with 1) configurations used in modern design, 2) load distributions that are representative of earthquake loading, 3) and consideration of soil-structure-interaction effects. The advanced experimental capabilities of the UIUC MUST-SIM NEES facility will permit realistic simulation of these complex conditions. Instrumentation developed as part of the MUST-SIM facility makes possible high-resolution monitoring of test specimen displacement fields and such data are necessary to enable the proposed model development effort. These data will be used to advance the state-of-the-art for simulation of reinforced concrete structures through the development of fiber-shell elements that can be used to simulate the inelastic response, including localized damage mechanisms, of three-dimensional walls. Results of the proposed experimental investigation and parametric studies using the high-resolution numerical models will be used to advance the state-of-the-practice for design of wall systems including the development of elastic and simplified inelastic modeling techniques that are appropriate for use with commercial software. Additionally, experimental and simulation data will be used to develop performance-based design tools that account for modeling uncertainty and link engineering demand parameters and damage states. BROADER IMPACT The structural engineering profession recognizes that the limitations identified above represent a significant gap in the development and implementation of performance-based seismic design provisions. To facilitate the transfer of the research result to practice, an External Advisory Panel has been assembled for the project that includes prominent structural engineers and members of structural engineering societies. An interactive website will be developed to disseminate research results to earthquake engineering professionals, educators and students to allow real-time viewing of experimental tests. In addition to educating today's engineers, the research team will use the research process and results to educate future engineers using the tele-observation capabilities at the NEES facility and education modules in design and analysis classes. The project team will leverage its own diversity and established programs in the colleges of engineering to reach a diverse student population. In addition to these activities, the team will work with college of engineering at UW, UICU and MUST-SIM group to reach K-12 students with activities such as Engineering Open House.