Seismic Simulation and Design of Bridge Columns under Combined Actions, and Implications on System Response

Status

Sequential Number

Matching Research Agency

University of Nevada and University of Missouri, Civil Engineering

Principal Investigator

Student Involvement

Two PhD students and two undergraduate students.

Project Objectives

The objectives of the proposed 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.

Project Abstract

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. Current analysis methods, behavior theories and design practices do not take into consideration the full range of interactions, due to the scarcity of experimental data and a lack of behavioral understanding. Therefore, the objectives of the proposed 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. The 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, and analytical models are calibrated by experimental data. A geographically distributed, highly qualified, diverse, multi-institutional, multi-national research team from NEES and non-NEES sites has been assembled that is ideally suited to undertake the scope. The experimental program includes quasi-static testing of twenty-eight large columns providing fundamental behavior including the impact of torsional moments at Missouri University of Science and Technology (UMR), pseudo-dynamic testing of five large and five small scale columns with variable axial load, within a bridge system simulation, at the University of Illinois at Urbana-Champaign (UIUC), real-time dynamic testing of twelve large scale columns with bidirectional and torsional inputs at University of Nevada, Reno (UNR), four tests provided by the University of Mexico (UNAM), plus an integrated experiment with three columns linked through simulation, conducted at UIUC by UMR. Fragility analysis will be undertaken, leading to the derivation of probabilistically-based fragility relationships for bridges subjected to combined loading. Simplified analysis and design tools will be developed as well as the necessary code language to change the existing practice. Extensive coordination has already begun between the US and Japanese researchers in an effort that culminates with large-scale testing on the E-defense table.

Anticipated Benefits

The proposal addresses two critical issues for the future performance of reinforced concrete bridges. These are (i) the effect of combined actions on the behavior and design of bridge columns, and (ii) the interaction of these columns with the entire bridge system. The intellectual merit of the proposal therefore derives from addressing two related problems for which there is no current solution, and using the outcome to derive behavior models and design guidance to reduce damage and improve the safety of transportation systems in future earthquakes.

The project milestones and deliverables impact a wide range of communities, including but not restricted to young students to graduate students and practicing engineers. Educational modules will be developed at all level thus having an impact on all levels of education. Design and analysis methods will be derived that will affect the earthquake design practice in the US and internationally.

Modal Orientation

Bridges testing and bridge assessment for seismic

Milestones

Relationship to other Research/Projects

NA

Technology Transfer Activities

An integrated education, training and outreach program has been developed that spans 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.

Transportation Research Board Keywords

Bridges, Bridge Piers