Project Title/ID Number Bridge Bent Shaking Table Validation Tests—5272002
Start/End Dates 10/1/02—9/30/03
Project Leader Steve Mahin (UCB/F)
Team Members Andreas Espinoza (UCB/Grad Student), Mahmoud Hachem (UCB/Grad Student), Eric Anderson (UCB/Grad Student), Peter Symonds (UCB/Undergrad Student)
Project goals and objectives

The goal of this project is to conduct a test on a simple reinforced concrete model bridge system, resulting in development of validation data on nonlinear response, component yielding/damage, and internal force redistribution during ductile response.

Role of this project in supporting PEER’s vision

This project support activities in Thrust Area 5 to better understand the behavior of bridge systems and characterize their capacity. Specifically, it provides data for the calibration and improvement of openSEES models of indeterminant reinforced concrete bridge structures undergoing three-dimensional excitations. It directly supports the bridge test bed activities.

Methodology employed
A series of structural models are designed, constructed and tested on the shaking table. The specimens are carefully instrumented to allow determination of local response and damage parameters used in the PEER methodology. Focus is on obtaining data to calibrate the openSEES modeling capabilities for ductile reinforced concrete bridges, and in conjunction with those working on openSEES improve modeling capabilities. The main specimens will consist of a two-column frame from a single column viaduct. The two columns will have different strengths and stiffnesses, resulting in different sequence and intensity of damage in each, significant redistributions of internal forces, and producing three-dimensional response including torsion. This data will then be compared to predictions made using openSEES models having different levels of complexity, ranging from conventional design assumptions, to highly refined models to assess local behavior.
Brief description of past year’s accomplishments and more detail on expected Year 6 accomplishments

This is the second year of this project. A final report (Hachem thesis) on the first milestone is nearly complete, assessing the ability of openSEES to model the behavior of single columns. Test specimens were designed, analyzed and constructed by late 2002. They are currently waiting availability of time on the shaking table to complete the tests. Various analyses of the models are being done to finalize selection of earthquake excitations for testing and instrumentation is being completed. Testing is expected to commence shortly.

Other similar work being conducted within and outside PEER and how this project differs

Similar experimental work has been carried out by researchers in Japan. The details and configurations used in those tests differ significantly from those considered common in US bridges. Analytical correlation studies are also underway in Taiwan, Japan and the US. Nearly all of these studies are based on results of quasistatic component tests, not using results from indeterminant shaking table tests. However, we remain in close contact with our counterparts in the US and other countries.

Plans for Year 7 if this project is expected to be continued

It is expected that the major work for this project will be completed during year 6. However, because of delays in accessing the shaking table, some of the planned analyses and completion of the doctoral dissertation by Andres Espinoza may continue into year 7. Mr. Espinoza is the recipient of a PEER graduate study fellowship; so additional funding is not anticipated.

Describe any instances where you are aware that your results have been used in industry

Results of tests have been used to assess likely damage in bridge columns by Caltrans and others.

Expected milestones

The first milestone is to complete model assessment for ductile reinforced concrete columns, using OpenSees focusing on effects of degree of refinement in model and ability to predict residual displacements (June 2002). The second milestone is to design and conduct studies on shaking table tests on a two-column test specimen (December 2002). The third milestone is to define an appropriate second test specimen, based on the results of the first specimen, and to support the testbed program (July 2003). Basic data on the completed test will be available September 2003.


Report on bridge column modeling, design and construction of the first test series, and testing initiated during year 5. Completion of tests, analysis of results, design, construction and testing of second series competed, along with preparation of final report.