The Oregon Department of Transportation (ODOT), like most other bridge owners, is faced with addressing this aging bridge problem. The latter is especially true on structures with significant performance concerns. Knowledge of the history and current status of the in-service performance of these structures can greatly benefit both prioritizing the responses and assuring reliability of the structure. Yet the owner must provide a very high level of reliability in these structures if they are to remain in service. Even with a well thought out prioritization, many structures will be years out from being fully addressed. A limited amount of funding and personnel will require all owners to prioritize the structures for problem resolution. The need for action has already exceeded the ability of many owners to respond with full implementation of these three common approaches to dealing with the problem. Thus a large number of bridge structures in our infrastructure are past, currently or soon to be due for major maintenance, retrofitting or replacement. A very large number of structures were put into service during the 1950 s and 1960 s which are now of the age where the performance or capacity of the structure has deteriorated or can no longer meet higher levels of demand. Key words: Structural Health Monitoring, SHM, Highway Bridge, Fatigue Cracking, Diagonal Tension Cracks, Movable Bridges, Bridge Foundations, Cathodic Protectionģ 1.0 INTRODUCTION Highway bridge performance and deterioration have been of great concern to owners and maintenance engineers for many years. Recommendations on when and how to apply SHM to highway bridges are presented. Brief examples of each system will be presented including a description of the problem or deficiency of concern, the physical measurements being taken, example results of the performance data and cost breakdown of the SHM system design and installation. Other examples include aero-elastic vibration concerns on a large through truss and cathodic protection systems on concrete bridges. Examples of the fourth category include two steel box girder bridges which have developed fatigue cracking related to either or both distortion and thermal strain loading. NE, Room 301 Salem, OregonĢ two vertical lift and one swing span movable bridges. Examples of the third category include 1 Senior Engineer, Oregon Department of Transportation Bridge Engineering Section, 355 Capitol St. Examples of the second category include two vintage RCDG structures suffering diagonal tension cracking in the girders. Examples of the first category include a bascule movable bridge and a concrete arch foundation. Bridges that have received SHM systems fall into 1 of 6 categories: 1) bridge foundations, 2) concrete superstructures, 3) movable bridges, 4) steel fatigue, 5) structural dynamics and 6) corrosion protection. Currently 10 bridges have dedicated SHM systems installed which measure and collect performance data and transfer the data to a central computer server for convenient monitoring and analysis. 1 APPLICATIONS OF STRUCTURAL HEALTH MONITORING TO HIGHWAY BRIDGES By Steven Lovejoy 1 Abstract The Oregon Department of Transportation s Bridge Engineering Section has developed and implemented a Structural Health Monitoring (SHM) program to facilitate the maintenance and performance measurement of selected highway bridges.
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