Bridge Evaluation, Repair and Rehabilitation

Evaluation, repair and rehabilitation of bridges are increasingly important topics in the effort to deal with the deteriorating infrastructure. For example, in the United States about 40 percent of the nation's 570,000 bridges are classified, according to the Federal Highway Administra tion's (FHW A) criteria, as deficient and in need of rehabilitation and replacement. In other countries the situation is similar. FHW A estimates the cost of a bridge replacement and reha bilitation program at 50 billion dollars. The major factors that have contributed to the present situation are: the age, inadequate maintenance, increasing load spectra and environmental contamination. The deficient bridges are posted, repaired or replaced. The disposition of bridges involves clear economical and safety implications. To avoid high costs of replacement or repair, the evaluation must accurately reveal the present load carrying capacity of the struc ture and predict loads and any further changes in the capacity (deterioration) in the applicable time span. Accuracy of bridge evaluation can be improved by using the recent developments in bridge diagnostics, structural tests, material tests, structural analysis and probabilistic methods. There is a need for an international exchange of advanced experience to increase the research effi ciency. The Workshop is organized on the premise that the exchange of existing American and European experience in the area of bridge evaluation, repair and rehabilitation is beneficial for both parties involved.

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Proceedings of the NATO Advanced Research Workshop, Baltimore, Maryland, USA, April 30-May 2, 1990

Contenu
I Management.- Bridge Management the Answer to the Challenge.- DANBRO A Bridge Management System for Many Levels.- Emerging Methodologies for Bridge Management Systems.- A Network Optimization System for Maintenance and Improvement of California's Bridges.- State of the Art for Control of Bridge Approach Settlement.- II Diagnostics and Monitoring.- Diagnostic Procedures for Bridges.- Long-Term Monitoring of Bridge Deformation.- Flaw Detection in Concrete Using the Impact-Echo Method.- Applications with Optical Fiber Sensor Systems for Monitoring Pre stressed Concrete Structures.- Detection of Structural Changes in a Bridge Model.- Detection, Diagnosis and Monitoring of Cracked Prestressed Concrete Bridges.- Modal Technology for Damage Detection of Bridges.- A Dynamic Method for the Safety Inspection of Large Prestressed Bridges.- Improved Structural Monitoring with Acoustic Emission Pattern Recognition.- Diagnosis of Reinforced Structures: an Active Microwave Imaging System.- Monitoring Prestress Forces in a Box Girder Bridge.- Assessment of Bridge Deck Repairs by a Non-Destructive Technique.- Dynamic Characterization of Posttensioned Rods in Stressed Timber Systems.- Techniques for Assessing the Concrete (State) Condition in Bridges.- III Loads and Analysis.- Fatigue Loading and Design for Road Bridges.- Bridge Load Models and Truck Weight Regulations.- Dynamic Behavior of Bridges Under Full Traffic.- Finite Element Modeling and Bridge Reliability Evaluation.- Probability Based Load Models of Highway Traffic for ULS and SLS Analysis.- Distortion-Induced Fatigue Cracking of a Non-Composite Steel Girder-Floorbeam-Stringer Bridge.- Non Linear Interaction of Longitudinal and Transverse Load Effects in Concrete Box Girder Bridges.- IV Evaluationand Tests.- Evaluation of Bridges European Perspective.- Utilization of Service Loads in Bridge Evaluation.- Prestressed Concrete Girders After 20 Years in Service.- Dynamic Testing of Bridges Using Traffic-Induced Vibration.- Measured Stresses in the Deck Segments of a Cable-Stayed Bridge.- Evaluation of an Old Prestressed Concrete Bridge.- Instrumentation of a Cable Stayed Bridge at Skagway, Alaska.- Full Scale Testing of Steel Railway Bridges.- Static Strength Tests of Steel Plate Strengthened Concrete Beams.- V Repair and Rehabilitation.- Bridge Repair Methods US/Canadian Practice.- Structural Strengthening by External Prestressing.- Strengthening of a Three-Span Continuous Bridge by Post-Tensioning.- Cathodic Protection of Reinforced Concrete Structures Experimental System Installed on a Viaduct in Service on the IRI-ITALSTAT Network.- Rehabilitation of Steel Truss Bridges in Ontario.- Reinforcement of N9 Motorway Bridges Over the Lutrive Valley Near Lausanne Switzerland.- Fiber Composites for Bridge Rehabilitation.- Rehabilitation of the Harry W. Nice Memorial Bridge.- Durability of Concrete Bridge Decks with Reduced Reinforcement.- VI Working Group Reports.- I. Bridge Management.- II. Bridge Diagnostics.- III. Bridge Evaluation.- IV. Bridge Repair.- Index of Subjects.- Index of Authors.