Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Compact Retrofitted Adaptive Stiffeners for Extending Remaining Life in Existing Bridges
An approach to controlling stress in existing bridge structures using a system of distributed actuators within steel girder spans has been studied. The number of actuators per typical bridge span was fixed at three pairs but the corresponding length of each actuator assembly was optimized at 16 ft. Simulation results for the model bridge while traversed by a representative model heavy truck at 65 mph gave induced maximum bending moment reductions of more than 37%, and induced reversed bending moment reductions of more than 31%. This performance is better than the 25% reduction in bridge girder bending stresses reported in an extensive study at the University of Oklahoma, which however utilized a single pair of large actuators in each retrofitted bridge span. Although the smaller, more compact actuators considered in this study, which have their moment arms attached to the low-stress neutral axis region of the girder, are capable of higher operating axial thrust, the present vibration reductions were obtained using practical actuator forces whose peak levels were within the design specifications of the Oklahoma study, and were guaranteed by pressure dump means incorporated into the actuator hydraulic circuit design. The current research also predicted a not very significant difference in the performance of a sufficiently stiff distributed intelligent stiffener assembly, under a semi-active controller and a passive (valve-closed) controller, therefore recommending the less complex but more practical and easily realized passive bridge stiffener control system for effective vibration stress mitigation in steel girder bridges.
Compact Retrofitted Adaptive Stiffeners for Extending Remaining Life in Existing Bridges
An approach to controlling stress in existing bridge structures using a system of distributed actuators within steel girder spans has been studied. The number of actuators per typical bridge span was fixed at three pairs but the corresponding length of each actuator assembly was optimized at 16 ft. Simulation results for the model bridge while traversed by a representative model heavy truck at 65 mph gave induced maximum bending moment reductions of more than 37%, and induced reversed bending moment reductions of more than 31%. This performance is better than the 25% reduction in bridge girder bending stresses reported in an extensive study at the University of Oklahoma, which however utilized a single pair of large actuators in each retrofitted bridge span. Although the smaller, more compact actuators considered in this study, which have their moment arms attached to the low-stress neutral axis region of the girder, are capable of higher operating axial thrust, the present vibration reductions were obtained using practical actuator forces whose peak levels were within the design specifications of the Oklahoma study, and were guaranteed by pressure dump means incorporated into the actuator hydraulic circuit design. The current research also predicted a not very significant difference in the performance of a sufficiently stiff distributed intelligent stiffener assembly, under a semi-active controller and a passive (valve-closed) controller, therefore recommending the less complex but more practical and easily realized passive bridge stiffener control system for effective vibration stress mitigation in steel girder bridges.
Compact Retrofitted Adaptive Stiffeners for Extending Remaining Life in Existing Bridges
I. Eronini (Autor:in) / A. B. Davy (Autor:in)
2004
72 pages
Report
Keine Angabe
Englisch
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