Phase I Benchmark Control Problem for Seismic Response of Cable-Stayed Bridges

This paper presents the problem definition for the first generation of benchmark structural control problems for cable-stayed bridges. The benchmark problem is based on a cable-stayed bridge that is currently under construction in Cape Girardeau, Missouri, USA. Construction of the bridge is expected to be completed in 2003. The goal of this study is to provide a testbed for the development of strategies for the control of cable stayed-bridges. Based on detailed drawings of the Cape Girardeau bridge, a three-dimensional evaluation model has been developed to represent the complex behavior of the full scale benchmark bridge. The linear evaluation model is developed using the equations of motion generated around the deformed equilibrium position. Evaluation criteria are presented for the design problem that are consistent with the goals of seismic response control of a cable-stayed bridge. Control constraints are also provided to ensure that the benchmark results are representative of a control implementation on the physical structure. Each participant in this benchmark bridge control study is given the task of defining (including devices, sensors and algorithms), evaluating and reporting on their proposed control strategies. These strategies may be either passive, active, semi-active or a combination thereof. A simulation program has been provided to facilitate direct comparison of the capabilities and efficiency of the various control strategies. The problem has been made available for downloading through the internet in the form of a set of MATLAB® equations. A sample control design is included to guide participants through the benchmark problem. Introduction In recent years benchmark problems have been recognized as a means to compare and contrast various structural control strategies (Caughey, 1998). Benchmark structural control problems allow researchers to apply various algorithms, devices, and sensors to a specified problem and make direct comparisons of the results in terms of a specified set of performance objectives. Additionally, these problems may include control constraints and hardware models to more accurately portray the types of implementation issues and constraints one must consider in reality. All of the benchmark problems considered so far have focused on the control of buildings. The first generation benchmark problem provided a comparison of control algorithms for seismically excited laboratory scale buildings. Researchers reported their results for this problem at the 1997 ASCE Structures Congress, held in Portland, Oregon. Subsequently, a special issue of Earthquake Engineering and Structural Dynamics was devoted to the results of this benchmark 1. Associate Professor, Dept. of Civil Engineering, Washington University, St. Louis, MO 63130 (Corresp. Author). 2. Grad. Res. Asst. & Doct. Cand., Dept. of Civil Engineering, Washington University, St. Louis, MO 63130. 3. Assistant Professor, Dept. of Civil Engineering, Izmir Institute of Technology, Izmir, Turkey (work performed while a doctoral student, Dept. of Civil Engineering, University of Illinois). 4. Professor, Dept. of Aeronautical Engineering, University of Illinois, Urbana, IL 61801. 5. Associate Vice President, HNTB Corporation, 715 Kirk Drive, Kansas City, Missouri, 64105.