Reinforced concrete structural walls are one of the most common lateral-force-resisting systems used worldwide. In regions with ductile detailing practices, common designs rely on transverse reinforcement to confine the wall boundaries. In thin walls, cover spalling can lead to damage requiring repair. The spalled cross sections also can become too thin to reliably support axial forces, leading to wall lateral buckling. This study will explore alternative mechanisms to reduce cover spalling, thereby improving safety and post-earthquake repairs. Possible approaches include use of high-performance fiber reinforced concrete and addition of buckling-restrained boundary elements. The study will be a companion study to a larger test program under way at UC Berkeley. Each undergraduate student will be assigned a specific, largely independent study topic that they will carry through from inception through construction, testing, and reporting.

While experiments are done in the laboratory to provide information needed to improve analysis methods and devise more effective design methods, the largest and most realistic source of information is from the response of actual engineered structures to earthquakes. This research project will focus on one type of structure such as hospitals, tall buildings, unreinforced masonry structures, bridges, residential housing, etc. (selected based on the student's interest). The research will utilize the new PEER structural performance information management system. To maximize learning from past and especially future earthquakes, the student will help develop pre- and post-event plans for gathering quantitative information about the type of structure selected, and begin gathering and interpreting information according to the plan developed. Particular structures selected might be ones are instrumented or located near strong motion instruments, have been studied or inspected following past earthquakes, have been retrofit, have been identified as being vulnerable to future earthquakes, provide a particular crucial role in post-earthquake emergency response or recovery,etc.). The student will work with faculty, students and researchers working on this project, and learn a lot about the performance of engineered structures during earthquakes.

A novel process in which bacteria are used to transform loose liquefiable sand into sandstone is being developed. Critical to field implementation of this technology is developing the technique stimulate native bacteria in natural soils for cementation. This research project will consist of gathering soil samples from different locations in northern California, preparing specimens of the soil in the laboratory, treating the soil to induce cementation, and then assessing the extent to which their potential for liquefaction has been reduced. This project is experimentally based and will occur primarily in the laboratory. During this project the student will be exposed to geotechnical, microbiological, and geophysical techniques, and will work in collaboration with the faculty advisor and other graduate students.

Intermediate soils – clayey sands, silty sands, etc. – exist in widespread deposits beneath many of California’s dams and levees. Characterization of these materials is difficult since their behavior and engineering properties depend on the drainage conditions during loading. If loading is sufficiently slow they behave similar to a sand, while if their loading is rapid they behave more similar to clay materials. This project will include laboratory and model or field testing of intermediate soils from different levee/dam sites to assess how their behavior varies as a function of drainage conditions. Visits to field locations may also be necessary. This project self-standing, but will also link with and leverage data and knowledge generated by other research activities in the group.

This work will examine the variety of ways that probabilistic levee failure can be estimated and represented for larger levee risk analysis modeling. Example failure mechanisms include overtopping, erosion, slope failure, and boils. This will mostly be an organization of the literature on probabilistic representation of levee failure. Some familiarity or interest in probability and geotechnical engineering is desirable.

Risk-based analysis is often employed or advocated for a single levee. This work involves identifying optimal designs for systems of levees considering probabilistic performance, construction costs, and flood damage consequences. Example applications will be to the Central Valley of California. Optimization will includes models mostly in spreadsheet form. Some familiarity or interest in probability and system modeling is desirable.

UW researchers have developed a precast column and cap-beam bridge bent system that can be constructed much more rapidly than conventional cast-in-place bents. This feature greatly reduces the traffic congestion caused by construction activities. The system, which was deployed in a bridge over I-5 in 2011, is expected to perform similarly during earthquake as conventional bents. To improve the expected seismic performance (e.g., reduce damage, decrease residual displacements), the system is being modifed to incorporate column pretensioning and high-performance, fiber-reinforced concrete. Two interns will assist a graduate student in testing two column-to-footing subassemblies. In addition, each of the students will be responsible for analyzing and documenting the data from non-contact instrumentation for one of the tests, and comparing it with the results of previous datasets.

Structural integrity requirements for steel structures are aimed at ensuring that localized failures to do not result in disproportionate collapse of structures, i.e., that local failures remain local. An often overlooked component of ensuring structural integrity is ensuring that steel gravity frames (i.e., those frames not associated with the lateral force resisting system) are robust and can limit collapse in the event of unanticipated local failures, specifically if the gravity frame columns are damaged. UW researchers have been testing common steel gravity frame connections under combined loading (shear, moment and axial load) to determine their strength, ductility and overall robustness when subjected to such demands. One intern will assist a graduate student in testing several connections. They will have primary data analysis responsibilities for at least one connection test and will also develop a simplified computer model of the connection that could be used in a structural engineering design office.

Geotechnical earthquake engineers can learn a great deal about the response of soil deposits and the behavior of soils within them from ground motion records from vertical arrays. A vertical array is a set of ground motion instruments located at different depths within a soil profile; typical vertical arrays include triaxial accelerometers and some also include piezometers for measurement of porewater pressure. A vertical array, the Seattle Liquefaction Array (SLA), including both accelerometers and piezometers was recently installed along the Duwamish River just south of downtown Seattle. The SLA site is underlain by different layers of potentially liquefiable soils, and is one of a very small number of such arrays. This project will involve preparing a detailed characterization of the SLA site including collection of subsurface and laboratory test data, performance of cyclic triaxial tests on samples of liquefiable soils from the SLA area, analysis of weak motions already recorded at the SLA, prediction of SLA site response under stronger levels of shaking, and development of a simple website describing the SLA and its characteristics. The student will undertake both experimental and analytical work, and will interface with geotechnical engineering and seismology researchers at the University of Washington, and with local consultants involved with the planning and installation of the SLA.