Intellectual Merit: The primary technical objective of the proposed study is to conduct a comprehensive investigation of the seismic performance of a series of models of four-span large-scale bridge systems including the soil-structure interaction effects at the footings and the abutments. A strong interdisciplinary team of researchers is formed to lead the effort in the study of the shake table response of bridge models, soil-structure interaction, numerical simulation, innovative materials, and wireless sensors with an overarching effort in education and outreach and utilization of information technology. Two leading international collaborators and representatives from the design profession will be also involved. Through the use of NEESgrid system and its tools, the team members and their students will closely collaborate in his multi-faceted study. Extensive numerical and physical simulation studies are envisioned, with the former using program OpenSees and the latter using the NEES shake table facilities at the University of California, San Diego (UCSD) and the University of Nevada, Reno(UNR). A large-scale abutment will be tested at UCSD and four, large-scale, 4-span bridge models will be tested at UNR. The UCSD studies will provide data that will be used in simulating the abutment input motion in the UNR tests. Two of the bridge models will incorporate conventional design, the third will be supported on fiber-reinforced polymer (FRP) composite piers, and the fourth will incorporate innovative column plastic hinges with minimum permanent damage. The major gap that the proposed study will address is experimental data and calibrated analytical studies of the earthquake performance of bridge systems. Unlike past studies that have generally been on components, the proposed research will include system response in addition to component behavior. Modern wireless sensors will be further developed as a part of this project and used in the shake table studies. The results of the study are expected to facilitate the evaluation of existing and emerging bridge seismic codes, provide information for performance-based seismic design, help understand the system response, determine the effectiveness of FRP piers, evaluate potential of wireless sensors in large-scale testing, and demonstrate the feasibility of innovative serviceable bridge columns after strong earthquakes. New data and metadata models are envisioned to facilitate incorporation of the new information obtained in the project in the data repository planned by the NEES Consortium.
Broader Impact: The broader impact of the proposed project will consist of its strong educational thrust and it overall societal impact. Through the new knowledge generated as a results of this project in multiple forms, the study will (1) directly train post-doctoral fellows, graduate students, and undergraduate students at several universities using the latest state-of-the-art technology in earthquake engineering research and information technology,(2) educate K-12 students, teachers, and the public about bridge earthquake engineering, (3) integrate teaching and research at introductory and advanced college courses, (4) develop teaching modules for high schools, (5) develop an interactive website, (6) improve basic understanding of the societal role of earthquake engineers, and (7) motivate K-12 students to increase the likelihood of all talented students, women, minorities, and others to seriously consider earthquake engineering as a profession. The overall societal impact of the proposed project will be (a)training of skilled earthquake engineers with state-of-the-art NEES equipment to improve the human resource pool, (b) improving public understanding and perception of the critical role of earthquake engineering in the society, (c)generating verified information based on research conducted by a strong team of multidisciplinary researchers from several US and two overseas universities,(d) providing impetus for reliable implementation of performance-based design of new and retrofit of existing bridges in design codes to ensure safe bridges and to reduce economic loss in future strong earthquakes, (e)increasing the awareness of the earthquake engineers about innovative materials and their potential to keep bridges operational even after strong earthquakes, (f)improving global understanding by interaction and international exchange opportunities provided by this project with international collaborators, and (g)providing opportunities for several potential payload projects that could further enhance the growth of a number of high caliber faculty, several of whom are recipients of past NSF Career or other awards.
Standard bridges are designed to survive strong earthquakes without collapsing. However, these bridges are allowed to be severely damaged to absorb the earthquake energy. The design goal is to prevent the bridge from collapsing thus saving lives. The goal is not to save the bridge because it would not be cost effective. This study was aimed at developing methods to not only save lives but also save the bridge so it can be kept open to traffic after a strong earthquake. Through this project, novel materials such as Nickel Titanium, rubber element, glass composites, carbon composites, and concrete with special fibers were studied, and new construction methods were developed to save lives and the bridge. To conduct this comprehensive research, it was necessary to use four high-capacity shake tables, three at the University of Nevada, Reno, and one at the University of California, San Diego. Additional bridge test facilities at the Florida International University and wireless sensor laboratory at Stanford University were used. Considering the diversity of the issues and novel ideas that were incorporated in this project, researchers from five universities joined forces to address different aspects of the project: University of Nevada, Reno, University of Texas, Austin, Florida International University, University of California, Berkeley, University of California, San Diegeo. Integration of the results and testing of three, large-scale four-span bridges were conducted at the University of Nevada, Reno. Because the movement of bridges during earthquakes is complex and considering that several novel ideas were studied, preliminary tests of some of the components were done at collaborative universities. Extensive computer simulation was also carried out to maximize the lessons learned from this research. Several novel designs for bridge columns emerged from this study that included a combination of Nickel Titanium and concrete with fibers, rubber elements with special details, tubes that are made of glass fibers and filled with concrete, and columns that are made of segments but are reinforced with carbon fiber sheets. The methods that were developed are being transferred to practice on a trial basis in actual bridges. The novel materials are also being utilized to make bridges of the future more energy efficient by designing them so they can be recycled. Over 25 students, research associates, and professors were involved in the projects. The project contributed toward preparing experts in bridge earthquake engineering for designing, constructing, and conducting research in the future. A workshop was held with 40 experts consisting of federal and state bridge designers, consulting engineering, academics, and representatives from novel materials industries to help develop a roadmap of implementation innovation in bridges of the future.
