Benchmark structural control problem for a seismically excited highway bridge-Part I: Phase I Problem definition (original) (raw)
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A nonlinear damping control for the vibration mitigation of the benchmark highway bridge
Structural Control & Health Monitoring, 2009
Active, passive and semi-active controls have been extensively considered to improve the protection of structures against earthquakes. In this paper, we present a new nonlinear damper, which is then applied to a three-dimensional benchmark structural control problem for seismically excited highway bridge. The main feature of the proposed controller is the simplicity in formulation, design and implementation. It is based on using a passive static hyperbolic function depending only on the base velocity. This function ensures energy dissipation capability with always bounded control force. The performance indices show that the proposed controller behaves satisfactorily and with a reasonable control effort. Copyright © 2009 John Wiley & Sons, Ltd.
Response simulation and seismic assessment of highway overcrossings
Earthquake Engineering & Structural Dynamics, 2009
Interaction of bridge structures with the adjacent embankment fills and pile foundations is generally responsible for response modification of the system to strong ground excitations, to a degree that depends on soil compliance, support conditions, and soil mass mobilized in dynamic response. This paper presents a general modeling and assessment procedure specifically targeted for simulation of the dynamic response of short bridges such as highway overcrossings, where the embankment soil–structure interaction is the most prevalent. From previous studies it has been shown that in this type of interaction, seismic displacement demands are magnified in the critical bridge components such as the central piers. This issue is of particular relevance not only in new design but also in the assessment of the existing infrastructure. Among a wide range of issues relevant to soil–structure interaction, typical highway overcrossings that have flexible abutments supported on earth embankments were investigated extensively in the paper. Simulation procedures are proposed for consideration of bridge-embankment interaction effects in practical analysis of these structures for estimation of their seismic performance. Results are extrapolated after extensive parametric studies and are used to extract ready-to-use, general, and parameterized capacity curves for a wide range of possible material properties and geometric characteristics of the bridge-embankment assembly. Using two instrumented highway overpasses as benchmark examples, the capacity curves estimated using the proposed practical procedures are correlated successfully with the results of explicit incremental dynamic analysis, verifying the applicability of the simple tools developed herein, in seismic assessment of existing short bridges. Copyright © 2009 John Wiley & Sons, Ltd.
Analytical Seismic Assessment of Highway Bridges with Soil-Structure Interaction
2000
The paper describes a new approach and its practical implementation for the analysis of the inelastic dynamic response of bridges with soil-structure interaction using multiple analysis platforms. The development is presented through an application test bed; the Meloland Road Over-crossing (MRO) bridge. The structure was heavily instrumented and has been shaken several times by significant earthquakes, rendering it an ideal
The seismic events occurred in recent years have highlighted the extreme vulnerability of a large part of existing constructed facilities and the need to adopt innovative solutions to improve their seismic performances. With this purpose, the possible exploitation of a seismic early warning system (SEWS) in the framework of semi-active (SA) structural control based on magnetorheological (MR) dampers is herein investigated. The main idea consists in changing the MR damper behavior according to an anticipate estimate, provided by the SEWS, of the peak ground acceleration (PGA) for an incoming earthquake. The adjustment is supposed to happen only once, just before the quake strikes. The application to a case-study problem (i.e. a highway bridge located in southern California) is shown, also allowing to assess the robustness of the proposed protection technique. Possible errors on estimation of PGA provided by SEWS and the way they affect the effectiveness of the control strategy are di...