Benchmark Structural Control Problem For Seismically Excited Highway Bridge
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Resume	Benchmark Problem- Introduction A benchmark problem for the seismically excited highway bridges has been presented as a test bed for response control highway bridges.  The problem package consisted of FEM model of the highway bridge in MATLAB, definition papers describing the problem in PDF format and computer programs to perform necessary analysis. Phase I Highway Benchmark Bridge: Bridge deck fixed to outriggers Abstracts: Benchmark Structural Control Problem for a Seismically Excited Highway Bridge, Part I: Problem Definition A.K. Agrawal, Associate Prof., Dept. of Civil Engrg., The City College of New York, New York Ping Tan, Post-Doctoral Researcher, Dept. of Civil Engrg., The City College of New York, New York Satish Nagarajaiah, Associate Professor, Rice University, Houston, TX. Jian Zhang, Assistant Professor, University of Illinois at Urbana Champaign, IL. This paper presents the problem definition of the benchmark structural control problem for the seismically excited highway bridge. The benchmark problem is based on the newly constructed 91/5 highway over-crossing in Southern California. The goal of this effort is to develop a standardized model of a highway bridge using which competing control strategies, including devices, algorithms and sensors, can be evaluated comparatively. To achieve this goal, a 3-D finite-element model is developed in MATLAB to represent the complex behavior of the full-scale highway crossing. The nonlinear behavior of center columns and isolation bearings are considered in formulating the bilinear force-deformation relationship. The effect of soil-structure interaction is considered by modeling the interaction by equivalent spring and dashpot. The ground motions are considered to be applied simultaneously in two directions. A MATLAB based nonlinear structural analysis tool has been developed and made available for nonlinear dynamic analysis. Control devices are assumed to be installed between the deck and the end-abutments of the bridge. Evaluation criteria and control constraints are specified for the design of controllers. Passive, semi-active and active devices and algorithms can be used to study the benchmark model. Participants in this benchmark study are required to define their control devices, sensors, and control algorithms, evaluate and report the results of their proposed control strategies. Benchmark Structural Control Problem for a Seismically Excited Highway Bridge, Part II: Sample Control Designs Ping Tan, Post-Doctoral Researcher, Dept. of Civil Engrg., The City College of New York, New York A.K. Agrawal, Associate Prof., Dept. of Civil Engrg., The City College of New York, New York This paper presents sample control system designs for the three-dimensional benchmark structural control problem for seismically excited highway bridge. Three types of sample control systems, namely nonlinear viscous dampers, ideal hydraulic actuators and magnetorheological (MR) fluid dampers, are designed and presented for comparison by participants in the study. For each of the three sample control system, a total of 16 control devices are considered to be placed orthogonally between the deck-ends and abutments for the reduction of earthquake induced vibrations of the highway bridge. An H2/LQG control algorithm is selected for the active case and a clipped optimal control algorithm is chosen for the semi-active case. To facilitate the controller design, an eigenmode reduction method is used to reduce the number of degrees of freedom of the initially elastic model to obtain a reduced-order model. However, the evaluation model to simulate the performance of control strategies is the full-order nonlinear finite element model. A Kalman filter is used to estimate states of the reduced-order model required for the applications of controllers for both active and semi-active controllers using selected acceleration and displacement measurements. The modeling and sample control system designs presented in this paper are for illustration purposes only, and are not intended to be competitive. Participants of this benchmark study are expected to employ more competitive control designs for their own control strategies. These control strategies may be passive, active, semi-active or a combination thereof. Data Download for Phase I Highway Benchmark I and II(Right Click on Links Below): Highway Bridge Definition Paper Highway Bridge Control Designs Paper Benchmark Problem Data & Programs Phase II Highway Benchmark Bridge: Bridge deck isolated from outriggers Semiactive Lyapunov Controller for Phase II Seismic Isolated Highway Bridge Benchmark Satish Nagarajaiah, Associate Professor, Rice University, Houston, TX 77005 Sriram Narasimhan, Post Doc. Researcher, Rice Univ., and Project Engineer, ABS Consulting, Houston, TX A. K. Agrawal, Professor, The City College of the City Univ. of New York, New York, NY 10031. Ping Tan, Post-Doc. Researcher, The City College of New York, New York, NY 10031 Recently, a benchmark problem has been developed to study seismically excited highway bridges. In the second phase of the aforementioned study, the bridge is isolated both at the abutments and at the central pier location. The isolation, though effective in reducing the superstructure responses such as mid-span accelerations, results in increased mid-span and isolator displacements. The performance of a newly developed Lyapunov semiactive controller in reducing the isolator and mid-span displacements is investigated analytically on this newly developed phase II full-scale three-dimensional seismically excited highway bridge. The bridge is isolated using nonlinear hysteretic bearings with a lead core on the inside and an elastomer surrounding the lead core. Magneto-rheological (MR) dampers are used to control the seismic responses of the bridge semiactively. The semiactive control devices are installed at the isolation level between the deck and the isolators on bridge piers and center column at ten locations, each location consisting of a single orthogonal pair to control the responses in both directions. The outputs allowed in the benchmark problem definition are used to design the controller and where velocity measurements are required, the accelerations are integrated using a filter that simulates integration. The performance of the controller is analyzed in terms of the performance indices defined in the benchmark problem definition. The results of the Lyapunov controller are compared with the results of the sample controller presented in the benchmark problem. Highway Bridge Phase II Paper Highway Bridge Benchmark Problem Phase II Data & Programs Request: After you have downloaded the data, please click here to send us an e-mail about your e-mail address and other contact information so that we can contact you about your possible participation in activities related to the benchmark problem. Currently Planned Activities: We are seeking participants for the 4^th World Conference on Structural Control and Health Monitoring in San Diego, California during 11-13 July 2006. Please contact us if you are interested. Important Notes: 1. The PDF file can be viewed and printed using Acrobat Reader 5.0 or higher. A free copy of Adobe Acrobat Reader for Windows, Machintosh and Unix computers can be downloaded from www.adobe.com.    PDF file is platform independent and can be printed from any computer. 2. Matlab software and other tollboxes required for computations can be purchased from Mathworks, Inc. 3. The MS Word and data files for Windows system have been compressed using WinZip utilities. You can download an evaluation version of WinZip  from www.winzip.com.   Please download current version of WinZip to avoid any problems in unzipping data. If you have any comments or questions or problems, please contact us.
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