Virginia Tech. John C. Duke, Jr. Engineering Science & Mechanics. John C. Duke, Jr.

Transkript

1 A New Paradigm for Health Management of Bridges

2 Presentation Overview Introduction AASHTO Grand Challenges SAFETEA-LU LTBP Is the Problem Unique? RCM A New Paradigm Design, Build, Maintain---Asset Management Spiral Design Conclusions

3 Introduction By 2015 half the world population p will live in cities National system worth $1.75 x with ih $139x10 9 /yr repair Recent examples argue for a new paradigm Overhead Signs Post-tension tendons Big Dig

4 AASHTO-Grand Challenges 1. Extending Service Life 2. Optimizing Structural Systems 3. Accelerating Bridge Construction 4. Advancing the AASTHO Specifications 5. Monitoring Bridge Condition 6. Contributing to National Policy 7. Managing Knowledge

5 SAFETEA-LU LTBP SAFETEA-LU-- Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users Most recent transportation bill Includes funding for Long-term Bridge Performance Program (LTBP)

6 Long-term Bridge Performance The National Bridge Inventory (NBI) 590, bridges nationwide ~ 40% are 40 years old with a design life of 50 years within the next 10 years nearly 240,000 bridges will be replaced The nonquantitative, subjective, highly variable, and nonspecific nature of these (NBI) data makes them inadequate for comprehensive life-cycle decision-support. A program of detailed inspections and periodic evaluations will be conducted to monitor and measure the performance of these bridges over an extended period of time (at least 20 years and preferably longer). Why Monitor? Support Asset Management? What Info is required?

7 Asset Management Life-Cycle Costs Cost of project planning Cost of design (set large part of life-cycle costs) Base design Design to avoid maintenance (over design) Design to include access and provide support Cost of Construction Cost of Operation and Maintenance Regular operation Monitoring implementation, instrumentation, personnel, training Poor planning and design eliminate some monitoring options or making implementation more expensive!

8 Is the Problem Unique? Reliability-Centered Maintenance A process used to determine the maintenance requirements of any physical asset in its operating context Functions and performance standards of the asset? What ways does it fail to fulfill function(s)? What causes each functional failure? What happens when each failure occurs? What is the consequence of a failure? What can be done to predict or prevent each failure? What should be done if there is no proactive task? (If there is a proactive task, should it be done?)

9 New Paradigm Integrate design, construction, and maintenance Design» The design can be built without negatively impacting serviceability.» The design, includes definitions of modes of deterioration for each component, along with specification of critical levels of deterioration.» The design accommodates reliable condition assessment to support effective maintenance. Construction» (As-built) does not reduces serviceability (induce residual stresses)» Does not negatively impacts reliable condition assessment. Maintenance (repair and rehabilitation)» Ati Action avoids negatively impacting reliable libl condition assessment.» For R&R components modes of deterioration are defined as well as critical levels specified.

10 New Paradigm -continued Effective structural health monitoring is developed that supports maintenance decision making. Maintenance decision making is developed that fully exploits effective health monitoring of critical modes of deterioration. Spiral Will knowledge developed by LTBP be integrated into design during the course of the monitoring program? Education of designers must be improved to insure awareness of deterioration mechanisms, support for maintenance (access and monitoring interfacing) Asset management strategies need to fully exploit capabilities provided by health monitoring technology

11 Conclusions Transportation systems are valuable public assets The public must demand cost-effective asset management Long-term bridge performance monitoring must be part of an effective asset management strategy A new paradigm that integrates design, build, and maintain must be adopted ( Education is a key element of the process!)