Seismic Vulnerability of the Highway System

Task D2-1: Intelligent Bearings - State-of-the-Art Review

Subject Area: Earthquake Protective Systems 
Research Year 2

Principal Investigator(s) and Institution(s)

George C. Lee and Michael Constantinou, University at Buffalo


The objective of this task is to review and assess advanced technologies that may be applicable to the development of intelligent bridge bearings for highway bridge applications, and develop a plan for moving these technologies into practice in future years under this project.


The focus in this task will be directed at various high performance materials and/or smart materials, as well as bearing system configurations and designs (e.g., shape memory alloys, low-power ER fluids, composite materials, fail-safe systems by addition of semi-active functions, etc.). It draws on and extends the results of an NSF/MCEER-sponsored workshop on advanced technology review for application to the protection of critical facilities against earthquake ground motions which was held in the summer of 1998. The work entails the collection, review, and synthesis of a large body of theoretical, analytical, and experimental research, in concert with the identification of bridge performance parameters that can be adequately modified by the application of these advanced technologies.

This task is closely related and will be coordinated with Tasks D2-2 and D2-3, which involve performing research on the high performance/smart materials that show promise based on the information obtained during this task. Relevant literature was collected during Year 1, some of which has been reviewed. However, the list of relevant publications from the aerospace and defense industries is extremely long, but may provide information on new materials or valuable insight on materials already identified under this task. It is therefore important that this task continue to search for promising materials so that all relevant advanced materials are carefully reviewed for their potential to provide useful properties for intelligent bearings. The task will be continued and will feed Task D2-2 and D2-3, which will be initiated as parallel tasks for Year 2. 

The preliminary observation on the limited literature review is that many advanced technologies have been developed for space and defense applications and that these may not be applicable to protect civil engineering infrastructure systems against strong earthquake ground motions. Bridges for example have unique characteristics such as low frequency range, large mass, small deflection requirements, and requirements for low cost, simple maintenance, and long-term durability. However, the performance of these technologies under various conditions will provide useful information regarding technologies proposed for bridge research Due to the PI's familiarity of the NSF sponsored MCEER study on semi-active systems, it has been determined that the system known as Real-time Structure Parameter Modification (RSPM) has good potential for the intended intelligent bridge bearing development.


Report summarizing the strengths and weaknesses of potential technologies and systems that can be tailored to development of "intelligent" bearings for bridge applications. The report will also include some analyses of the important issues that must be overcome in order to apply these technologies to bridges. This will be used in D2-2 and D2-3 so that a systematic research agenda can be established.

Technical Challenges

It is unlikely that this review will result in the identification of technologies that can be readily applied to civil engineering structures. Rather, the review will lead, and has already led, to the identification of specific research studies in Subtasks D2-2 and D2-3 that have potential for future application of intelligent protective systems for bridges.


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