ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/297030
40 | ASPIRE , Summer 2012 F H WA F H WA H ighway bridges form major links in the national transportation network. Their structural health is important because these bridges allow the public to travel from Point A to Point B safely with little interruption and predicta ble arrival time. The role of bridge preservation is vital in meeting these expectations. Deﬁnition Bridge preservation is defined by both FHWA and AASHTO as "actions or strategies that prevent, delay, or reduce deterioration of bridges or bridge elements, restore the function of existing bridges in good condition, and extend their life. Preservation actions may be preventive or condition-driven." The goals of preservation are to: • maintain bridges in good or fair condition by systematic, preventive, and regular maintenance, and • not allow the bridge to deteriorate into poor condition, which would cause condition-driven preservation actions to be taken. P r e v e n t i v e m a i n t e n a n c e i s a l o t l e s s demanding on resources than condition-driven preservation actions. States report that the cost-benefit ratio for preventive maintenance is very high. Bridge preservation encompasses preventive maintenance, rehabilitation, and repair activities. lessons from History I n 1 8 0 6 , P r e s i d e n t T h o m a s J e f f e r s o n authorized the federal government to plan and build the famous and historic Cumberland Road. The President appointed a Board of Commissioners to decide on the route through which the road would run. The congressional specification for building the road was very simple. The road was to be 66 ft wide with a stone surface covered with gravel. The bridges were to be of stone. Grades were to be leveled after the manner of good road construction. Cumberland Road was one of the first major improved highways in the United States that was built by the federal government. It was the first road in the United States to use the new Macadam road surfacing. Within a few years after the road was opened to traffic, Cumberland Road deteriorated as a result of heavy traffic and lack of funds for maintenance. Does this sound familiar? In 1822, Congress passed a bill authorizing the federal government to collect tolls to be used for maintenance. This bill was vetoed by President James Monroe on the constitutional grounds that it was an unwarranted extension of the power vested in Congress. President Monroe's position has continued to be the federal position on highway matters to present day. During the next nine years, Cumberland Road continued to deteriorate despite a few small federal appropriations for maintenance. It was finally recognized that the only solution was state-operation as a toll road. In 1831 and 1832, the state legislatures of Ohio, Pennsylvania, Maryland, and Virginia agreed to accept and maintain their sections of Cumberland Road. These states set the earliest example of meeting the challenges of maintaining roads and bridges in good condition. Systematic Preservation Systematic preventive maintenance is a key part of an effective preservation program. It is necessary for ensuring proper performance of the transportation infrastructure. Experience has shown that preventive maintenance is a very cost-effective way for extending the service life of highway bridges and structures. Congress finds and declares that it is in the vital interest of the nation that a highway bridge program: • enables states to improve the condition of highway bridges, • rehabilitates bridges that are determined t o b e s t r u c t u r a l l y d e f i c i e n t o r functionally obsolete, and • implements systematic preventive bridge maintenance. This r esult s in legislation that makes systematic preventive maintenance activities, s u c h a s c r a c k s e a l i n g , e x p a n s i o n - j o i n t repair, and controlling deterioration, eligible for Federal-Aid funds. A state may carr y out systematic preventive maintenance for a highway bridge without regard to sufficiency rating or deficiency status. Systematic preventive maintenance implies the use of an effective maintenance strategy or a prioritization and optimization preservation program to gain the most benefit from the investment on preventive maintenance activities to keep bridges in a state of good repair. Preservation of Concrete Bridges by M. Myint Lwin and Anwar Ahmad, Federal Highway Administration Deck delamination repair before application of an overlay. All photos: Virginia Department of Transportation. ASPIREBook_Sum12_R02.indb 40 6/29/12 12:39 PM