InTrans / Jun 21, 2021

LCCA tool evaluates costs for Iowa’s bridge decks

Life-cycle cost analysis cost inputs

The ability of agencies to incorporate life-cycle cost analysis (LCCA) into their bridge management programs has become more important as the gap between their maintenance needs and their available resources has grown.

To help agencies address that need, Bridge Engineering Center (BEC) Structure and Infrastructure Engineer and Associate Professor in the ISU Department of Civil, Construction and Environmental Engineering Alice Alipour developed a software tool that allows users to thoroughly and realistically evaluate and compare maintenance costs for bridge decks over a bridge’s lifetime. With this information, users can make investment decisions considering all maintenance costs during the period over which alternatives are compared.

“The main objective of this research project was to develop a user-friendly LCCA tool for Iowa’s bridges based on survival analysis of bridge condition ratings,” Alipour said. “The tool was designed to cover the most common types of bridges in Iowa while integrating historical data from various sources into the predictive models that account for the cost of maintenance and repair activities during a bridge’s service life.”

The developed LCCA tool focuses on bridge decks, with the possibility of potential extensions in subsequent implementation phases. Bridge decks were chosen due to the relatively abundant amount of data available for this component. Bridge data were sourced from experts in the field, Iowa’s Structure Inventory and Inspection Management System (SIIMS) database, and the National Bridge Inventory (NBI) database.

“The tool takes into consideration the deterioration rates specific to Iowa bridge decks at two-year time intervals and aims to predict the agency and user costs associated with preserving, rehabilitating, and repairing the bridge decks,” Alipour said. “This offers a unique advantage over Iowa’s current system, which selects projects based on the lowest bid or estimated initial cost.”

The software tool is a MATLAB-based application called LCCAM. The application is built around a deterioration curve for Iowa’s bridges that was derived using the project’s LCCA methodology and data from 24,000 bridges in Iowa.

Though the tool includes maintenance and repair components in its current form, Alipour expects that future iterations of the software will be modified to include additional components.

A second phase of the project got underway in March. It will develop an updated tool and a user’s manual after first taking into consideration various sources of uncertainty, adding an option to consider indirect costs, and seeking input from potential users.

More details on the completed first phase project is available here. More information on the second phase in progress is available here.