Market Need - U.S. Bridges:

“Corrosion” is a common electrochemical occurrence that most Americans encounter during their day-to-day experiences with older automobiles, household tools and other metal structures exposed to the environment. While most people understand that an inadequately protected metal structure will corrode or “rust” over time when exposed to the environment, they often do not consider the extraordinary magnitude to which this seemingly small problem scales with respect to national infrastructure and military assets. In an effort to better understand the impact of metallic corrosion on the national economy, the U.S. Department of Transportation (U.S. DOT) and members of Congress commissioned a national cost of corrosion study within an amendment to the 1998 Transportation Equity Act for the 21st Century (TEA-21). The study was conducted from 1999 to 2001 by CC Technologies and the Federal Highway Administration (FHWA) and determined the total annual direct cost of corrosion to the United States to be approximately 3% of the Gross Domestic Product (GDP), or over $300 billion. To arrive at this corrosion figure the study evaluated 26 industrial sectors in which corrosion was known to be a significant problem and reported the financial magnitude of the problem, current solutions, industry size, and the industry growth rate. This same study estimated that the annual indirect cost of corrosion to the United States accounts for an additional 3.5% of GDP.

Countless articles have reported on inadequate state and federal infrastructure maintenance budgets, structures being used well beyond their intended design lifetimes, and structurally deficient bridges going without repair. One such article presents the American Society of Civil Engineers’ (ASCE) 2009 Report Card on America’s Infrastructure giving an overall grade of “D” because the current infrastructure is poorly maintained, unable to meet current and future demands, and in some cases, unsafe. The severe state of the nation’s infrastructure was a key topic during the 2008 political debates and accounts for a large portion of the $780 billion American Recovery and Reinvestment Act of 2009. In fact, the $27.5 billion included in the American Recovery and Reinvestment Act for highway and bridge construction projects represents the largest infrastructure line item in the bill. The high profile media coverage of the nations failing infrastructure combined with the federal governments recent reinvestment in civil infrastructure clearly identifies that there exists an overwhelming need for a cost efficient method of monitoring and assessing the health nation’s infrastructure.

Data from the Federal Highway Administration (FHWA) can be used to quantify the need for intelligent infrastructure products within the U.S. civil infrastructure market. Of the 596,842 bridges in the United States, 12.4% (approximately 74,000) are structurally deficient. The national cost of corrosion study referenced above predicts that a minimum investment of $78 billion over the next 20 years will be required just to maintain the status quo, i.e., as many bridges will become structurally deficient as are refurbished. This same report estimates the annual direct cost of corrosion to United States bridges at $8.3 billion, with $500 million spent annually on bridge corrosion monitoring. Currently, federal agencies are required by the Federal-Aid Highway Act of 1968 (FAHA-1968) to complete biennial inspections of all federally funded bridges over 20 feet in length. This law also requires that the results of these inspections be reported to the FHWA’s national bridge inventory. In order to comply with FAHA-1968, state departments of transportation employ full time bridge inspection technicians. For example, to inspect the 4,939 of Maryland’s 5059 total bridges that are subject to FAHA-1968 regulation, the state of Maryland employs 18 full time bridge inspection technicians. Assuming that each bridge inspection technician works an average of 255 days per year, in order for the state of Maryland to comply with federal regulations, each bridge inspection technician must inspect at least one bridge every 1.6 days. States often fall behind such an aggressive inspection schedule and end up compromising public safety because they are unable to complete the required biennial inspections. Despite the aggressive inspection schedule in the above example, Maryland is actually one of the best performing states with only 0.2% of bridges past the 24 month inspection period. Other states like Hawaii, Rhode Island, and Arizona have over 25% of their respective bridges past the 24 month inspection deadline.

The large scale adoption of intelligent infrastructure technology will provide bridge inspection technicians with information that will solve several key problems with current bridge inspection practices. Namely, intelligent infrastructure systems will reduce the amount of time and money spent on bridge inspections by providing data from areas that are difficult and time consuming to access. Intelligent infrastructure systems will also quantify bridge inspections which have traditionally been somewhat subjective visual inspections. Lastly, intelligent infrastructure technology will increase bridge inspection technician safety by allowing the remote monitoring of areas that are dangerous to access.

Increased public awareness and political attention to aging infrastructure safety and maintenance cost problems, in combination with the current labor and capital intensive methods used to inspect and maintain this infrastructure, have created a significant need for intelligent infrastructure systems. A well designed intelligent infrastructure monitoring system consists of a user friendly software interface capable of displaying data from multiple sensors placed in functionally critical locations on the structure of interest. Intelligent Infrastructure systems leverage many of the benefits of the Condition Based Maintenance (CBM) systems used by the military and in private industry to reduce maintenance costs and increase equipment productivity. Specifically, long-term cost savings are achieved by using intelligent infrastructure systems capable of identifying developing faults before they become critical, and enabling the more accurate planning of preventive actions. Intelligent Infrastructure systems transcend the corrective maintenance (CM) and preventive maintenance (PM) policies currently used in the civil infrastructure industry. CM policy is the most primitive maintenance policy, where maintenance is only performed after the occurrence of a fault. PM policy improves upon CM policy by performing maintenance prior to structure failure; however, PM policy relies upon time-based maintenance (TBM) schedules. The federally required biennial bridge inspections provide a good example of a TBM based PM policy. The primary drawback of TBM schedules is that structures are inspected, repaired, or maintained solely based their age or time in use and not on the need for inspection or repair. This philosophy implies that structures of the same age and type are considered to have the same failure rate, regardless of the events that have occurred during construction or their operational lifetime. Clearly, this assumption is not correct or all structures of the same age would fail at the same time.

In summary, the large scale adoption of intelligent infrastructure technology will reduce the number of costly civil infrastructure failures, increase bridge safety and public confidence in civil infrastructure, and will streamline the bridge inspection process facilitating state DOT compliance with federal bridge inspection regulations.