BrM Quantity-Based Bridge Element Deterioration/Improvement Modeling and Software Tools

This study reviewed the state of the art and practice in bridge element deterioration / improvement modeling. It also developed a new and practical method for such modeling using element quantities in BrM inspection records along with bridge age. For reliable forecasting, this method uses these quantities directly to determine transition probability matrices (TPMs). The example TPMs were found age-dependent for the do-nothing case. Results show that this approach is effective in forecasting the bridge element life. Condition improvement TPMs were also similarly derived from the quantity evolution for consistency. Examples of renewal construction work are deck overlay of micro-silica concrete, steel beam repainting, bridge cleaning, etc. Two computer software programs in Microsoft Excel were developed to obtain TPMs for do-nothing deterioration and condition improvement. Bridge owners may use the tools to generate TPMs for any element whose inspection records are provided. As a result, TPMs can be continuously updated whenever more inspections are performed and their records are included as input to the software programs. In addition, the software tools are transparent for the user to perform expert elicitation, especially when the inspection records are questionable or unavailable. Such activity can be informatively guided by the results from the software, as illustrated by two application examples in the delivered programs. This new concept and associated tools may be applied by other bridge owners using the BrM system. Two application examples for elements 12 and 107 in the programs can be readily transplanted to other states as a starting point for application of the research products herein. They show that the age-dependent TPM is able to realistically replicate deterioration for the do-nothing case, particularly the behavior of faster deterioration while aging. They also demonstrate that TPMs for different renewal construction work are able to contrast their effectiveness, such as micro-silica overlays vs. sealing for a concrete deck.