Integration of Structural Health Monitoring (SHM) into Multilayer Statewide Bridge Maintenance and Management Practices – SHM-Facilitated Condition-Based Maintenance (SHM-CBM) Prioritization System TPF-5(219), 2018

For this project, the researchers developed a new structural health monitoring–facilitated condition-based management (SHMCBM) maintenance prioritization system. This system represents an important step toward more widely integrating SHM into practice. The kernel of the proposed SHM-CBM system is establishing a ranking index for each bridge in a particular inventory that establishes a maintenance funding priority for each bridge. A higher ranking index value indicates a lower maintenance funding priority. The ranking index is computed using both National Bridge Inventory (NBI) and SHM data, as well as user inputs. A case study of the I-80 Sugar Creek Bridge showed that replacement could be postponed by up to 37 years using SHM-CBM because the condition of the bridge was determined to be better than what was previously assumed. This potential extension of service life in combination with expected maintenance, repair, and monitoring costs were used in a cost-benefit analysis that showed SHM system implementation is financially justifiable. The SHM-CBM approach has the following advantages over current decision-making approaches: Continuous and near-real-time SHM data are used in decision making Wide range of quantitative data can be gathered using SHM (e.g., strain and temperature, chloride infiltration, tilt, and corrosion) Reduced uncertainty regarding structural performance Elimination or reduction of over-maintenance and deterioration or failure due to a lack of information about a bridge’s true conditio

Condition based bridge management with SHM integration: A novel approach to remaining life estimation of bridges

Bridge deterioration and aging are important problems in the United States. According to the infrastructure report card from the American Society of Civil Engineers, as of 2016, almost one in 11 (9.1%) bridges are structurally deficient and approximately 4 out of 10 (40%) bridges are older than 50 years. Rehabilitation cost for these bridges are estimated to be about $123 billion, pointing to the need for proper bridge management plans. There are many bridge management systems in the world. All of these lack of an integrated SHM system and are subject to criticism of being subjective. Condition-Based Maintenance (CBM) coupled with the Structural Health Monitoring (SHM) data can be used to actively manage bridges while minimizing subjective effects. The current research work consisted of two primary tasks. The first task was to update the current automated CBM-SHM framework developed at the Bridge Engineering Center (BEC) at Iowa State University (ISU), by improving its current load rating calculation process. The current load rating approach underestimates the rating factor of a bridge by 20% to 40%. The load rating calculation process was improved by developing a relationship between moment of inertia and flexural strength of bridges. An extensive experimental program was conducted to validate the relationship. The proposed method may significantly improve the rating factor of a bridge. The second task was to develop a novel condition rating prediction model to predict future condition ratings of the bridges. The condition rating information in the National Bridge Inventory (NBI) database was used in this development. The research group developed two different types of future condition rating prediction models, Current Practice Model (CPM) and Deterioration Prediction Model (DPM). CPM is capable of simulating the effects of historical maintenance activities and DPM does not consider the effects of historical maintenance activities when predicting the future condition rating probabilities. Both CPMs and DPMs were quantitatively and qualitatively validated