Semiactive Lyapunov Controller for Phase II Seismic Isolated Highway Bridge Benchmark

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.