Developing deterioration models for Nebraska bridges.

Nebraska Bridge Management System (NBMS) was developed in 1999 to assist in optimizing budget allocation forthe maintenance, rehabilitation and replacement needs of highway bridges. This requires the prediction of bridgedeterioration to calculate life-cycle costs. At the meantime, the approach adopted to predict the deterioration ofbridge components is based on national average deterioration rates, which are one drop in the deck condition ratingevery eight years and one drop in the superstructure and substructure condition rating every ten years. This approachdoes not account for the impact of traffic volume, structure and material type, and environment impacts, in additionto being not specific to Nebraska bridges.The objective of this project is to develop deterioration models for Nebraska bridges that are based on the conditionratings of bridge components (i.e. deck, superstructure, and substructure) obtained from bridge inspections since1998 up to 2010. The impact of governing deterioration factors, such as structure type, deck type, wearing surface,deck protection, ADT, ADTT, and highway district, is considered in developing these models.Recently, NDOR decided to adopt \u201cPontis\u201d, the BMS supported by the AASHTO, to avoid the frequent updates ofNBMS, which is costly and time-consuming. Pontis requires the use of a specific type of deterioration models (i.e.transition probability matrices), which are not available for Nebraska bridges. Therefore, another objective of thisproject is to develop Pontis deterioration models using the inventory and condition data readily available in theNBMS database. Procedures for updating the developed model will be also presented