INDOT Construction Inspection Priorities

Abstract

In the last decade, the Indiana Department of Transportation (INDOT) has experienced an increase in their construction projects (e.g., INDOT’s construction spending was $789 million in 2006 and increased to $1,081.4 million in 2010); while the level of its in-house inspection staff and resources has either remained the same or declined. There are different strategies to deal with the need for construction inspection resources and they may include strategies such as outsourcing the inspection of construction activities and using quality control and quality assurance certification programs to reduce the need for in-process inspection. One strategy that could reduce the inspection workload is prioritizing construction activities for inspection. However, reducing the number of inspections also has risks, such as functional failures and reduced design life, if defects are not identified before the work is covered. Thus, available inspection resources should be allocated to the activities with significant risk consequences due to reduced inspection. The objective of this study was to: (1) evaluate the current inspection practices of INDOT and (2) develop a risk-based inspection protocol to facilitate efficient allocation of available inspection resources to minimize the risks associated with reduced inspection. First, the current inspection practices implemented by INDOT, other State Departments of Transportation, and consulting firms were identified and compared. The comparison between the inspection practices revealed that there is consistency between INDOT’s and consultants’ and other State Departments of Transportation’s inspection practices. To develop a risk-based inspection protocol, first, the risk consequences associated with reduced inspection were identified for different transportation construction activities, based on the data collected from 20 site visits to INDOT projects. These risk consequences include short and long-term functional failures, reduced design life, reduced safety, and increased maintenance cost. Based on data collected from 23 state Departments of Transportation, 58 engineers and inspectors from the Indiana Department of Transportation (INDOT), and 20 inspection consultants in the Midwest, the subjective perceived probabilities associated with the occurrence of each risk consequence were encoded using fuzzy analysis. Using these subjective probabilities, the risk impacts due to reduced inspection were derived. The construction activities subsequently were prioritized based on the risk impacts associated with reduced inspection into five priority levels: high, medium-high, medium, medium-low, and low. The greater the risk impacts were due to reduced inspection, the higher the priority would be for inspection of that activity. The study also included identification of value added of inspection and the