NSF through NEHRP Grant No. NEESR-SG-0530737
Bridge columns are subjected to combinations of actions and deformations, caused by spatially-complex earthquake ground motions, features of structural configurations and the interaction between input and response characteristics.
Combined actions/loadings can have significant effects on the force and deformation capacity of reinforced concrete columns, resulting in unexpected large deformations and extensive damage that in turn influences the performance of bridges as vital components of transportation systems.
These effects should be considered in earthquake analysis and design of bridges so that significant earthquake damage and severe disruption of transportation systems can be reduced.
The objectives of this project are to develop a fundamental knowledge of the impact of combined actions on column performance and system response and to establish analysis and design procedures that include the impact at both the component and system levels.
These objectives will be realized by integrating analytical and experimental research where physical tests are driven by analyses and simulations that examine the system response of various bridge types under different loading conditions. The analytical models are calibrated by experimental data and then extended to system response.
The experimental program includes testing at multiple facilities around North America:
Fragility analysis will be undertaken, leading to the derivation of probabilistically-based fragility relationships for bridges subjected to combined action. Simplified analysis and design tools will be developed as well as the necessary code language to change the existing practice. Design and analysis methods will be derived that will affect the earthquake design practice in the US and internationally. Coordination of an integrated test program has already begun between the US and Japanese researchers. Analysis components will be done at UCLA, UIUC, UMR and UNR.
The work at the University of Nevada, Reno focuses on the development of refined analysis and shaking table tests of small-scale models of bridge columns subjected to different levels of biaxial, torsion and vertical loads through real time earthquake motions. The performance of the specimens will be assessed in terms of strength, deformation, energy dissipation and failure mode. These results will be used to validate analytical tools, developing new inelastic models for RCC under combined loadings and to propose new design methodologies.
Eight specimens were tested on the shake table facility at the University of Nevada, Reno under bidirectional excitation. One specimen configuration will be circular, while the other will be a cross section with interlocking spirals. The tests were held from June to September 2009.
You can download PDFs outlining each of the four tests held:
An integrated education, training and outreach program, lead by Washington University, will span from 4th graders to practicing engineers. Modules will be developed for teachers and professors that can be inserted in their courses. Modules will be used by the research team in summer camps, visits to local elementary, middle and high schools, undergraduate and graduate courses and in continuing education courses. Specific programs are targeted towards underrepresented groups. To achieve its objectives, the project will utilize the NEESit cyber-infrastructure, state-of-the-art instrumentation and high-speed data acquisition systems, the NEES equipment sites at UNR and UIUC and the non-NEES site at UMR, which has committed to joining NEESgrid.`
The NEES@University of Nevada, Reno equipment site is funded in part by the Geoge E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Program of the National Earthquake Hazards Reduction Program (NEHRP) of the National Science Foundation (NSF) under Award Number CMMI-0927178.