Challenge

The project, led by Deighton's implementation team, included pavement and bridge staff from Brampton. They began with loading over 300 bridges the City is responsible for and then developed the OSIM parameters to be used for the element and component bridge analysis as part of the bridge management system BMS). During the development of the BMS, two addional performance metrics were added: risk and asset value.

The challenge was to compare benefits between the two asset classes.

Solution

It was decided during the project the asset value would be directly related to the Bridge Condion Index (BCI). The BCI is a composite index that includes the condion of the bridge components, namely: accessories, approaches, culvert, embankment, substructure, superstructure and trusses. The BCI is a 0 to 100 scale index where 100 is a new bridge and it represents the overall health of the bridge. It is based on the Ministry of Ontario’s (MTO) methodology.

The Asset Value uses the same bridge components as the BCI and assigns a monetary value to each component in each of four condion states: Good, Fair, Poor and Very Poor based on the probability distributions calculated in dTIMS during the analysis. For example, a bridge that had 100% of all components in Good condion would an asset value equivalent to the replacement cost of the bridge. Both asset value and BCI can be used as objective functions in the dTIMS optimization.

Results

New performance metrics were developed that could be used to equitably compare pavements and bridges. Risk and asset value were computed.