Use of field testing in delaware's bridge management program
01 Jan 1999-
TL;DR: In this paper, researchers at the University of Delaware have been working with engineers at the Delaware Department of Transportation (DelDOT) to develop methods for integrating bridge field testing and in-service monitoring into DelDOT's bridge management efforts.
Abstract: Since 1994, researchers at the University of Delaware have been working with engineers at the Delaware Department of Transportation (DelDOT) to develop methods for integrating bridge field testing and in-service monitoring into DelDOT's bridge management efforts. Bridges have traditionally been evaluated and rated using rather simple analytical methods and without the use of site-specific data. Estimates of a bridge's load-carrying capacity made in this manner are often overly conservative. Because of the continued deterioration of our nation's bridges and the growing number of bridges that are being classified as "deficient", combined with limited financial resources in our bridge management programs, it is more important than ever that estimates of a bridge's capacity be as accurate as possible. Accurate condition assessments and load ratings can allow bridge engineers to more effectively manage their bridge inventories. This paper summarizes the efforts to date and gives specific examples of how bridge field testing and in-service monitoring have been used to enhance the bridge management efforts in Delaware.
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TL;DR: In this paper, a continuous RCS bridge was evaluated starting with an AASHTO load and resistance factor rating analysis, and a diagnostic test was then conducted to measure live-load strains which showed that the slab stiffness fit within cracked and gross section behavior.
Abstract: In New Mexico, many reinforced concrete slab RCS bridges provide service on interstates I-10, I-25, and I-40. The load rating for this type of bridge largely depends on the live-load moment in the slab. Consequently, the objective of this study was to determine a more accurate value for the equivalent strip width using higher level evaluation techniques. A continuous RCS bridge was evaluated starting with an AASHTO load and resistance factor rating analysis. A diagnostic test was then conducted to measure live-load strains which showed that the slab stiffness fit within cracked and gross section behavior. Furthermore, slab moments from finite element analysis agreed reasonably well with experimental moments derived using the average of the cracked and gross section modulus. From refined analysis, the equivalent strip widths for positive moment were 26.1 and 22.1% greater than those calculated by the AASHTO approximate method for the exterior and interior spans, respectively. The refined widths for negative moment were greater than AASHTO by 13.1 and 11.1%. This increase in the equivalent strip width reduced the live-load effects, which proportionally increased the rating factors.
14 citations
TL;DR: Results are presented from a series of six diagnostic load tests which have been performed over the first six years of the Indian River Inlet Bridge’s service life, enabling the bridge‘s baseline performance to be established and enhancing DelDOT’'s ability to operate and maintain the bridge.
Abstract: The management and maintenance of cable-stayed bridges represents a major investment of human and financial capital. One possible approach to reducing the cost while simultaneously improving the process is by utilizing structural health monitoring (SHM) systems to enable diagnostic load tests to be regularly and efficiently conducted. The Indian River Inlet Bridge (IRIB), a 533-meter long cable stayed bridge, was opened for traffic in 2012. From the very early stages of the design process, the Center for Innovative Bridge Engineering (CIBrE) at the University of Delaware (UD) worked with the Delaware Department of Transportation (DelDOT) and their design-build team of Skanska and AECOM to plan and install a comprehensive structural health monitoring (SHM) system. The SHM system is a fiber-optic based design with more than 120 sensors of varying type distributed throughout the bridge. The system, which not only collects data continuously during normal operation, has also been utilized during regularly scheduled controlled diagnostic load tests being used to monitor ongoing bridge performance. This paper will present results from a series of six diagnostic load tests which have been performed over the first six years of the bridge’s service life (just prior to the bridge’s opening, and then again at six months, one year, two years, four years, and six years). The results of these six load tests have enabled the bridge’s baseline performance to be established. They have also provided an opportunity to develop a process for comparing future biennial tests to the evolving database of results, thereby enhancing DelDOT’s ability to operate and maintain the bridge.
13 citations
01 Jan 2007
TL;DR: A commercially available diagnostic load testing system that combines the field testing equipment along with a software package for data interpretation, finite element modeling, and correlation of models to field data was evaluated as part of this study.
Abstract: According to the 2004 National Bridge Inventory, nearly 28% of Iowa’s 25,000 bridges are rated as structurally deficient or functionally obsolete. Many of these structures are rated so by traditional visual bridge inspection and codified rating procedures. With many of these structures needing replaced or repaired, the problem is compounded by increasing bridge project costs and decreasing funding for such projects. A diagnostic tool is often necessary to accurately quantify the actual behavior and load carrying capacity of these deficient structures. Iowa State University recently completed an evaluation of a commercially available diagnostic load testing system that combines the field testing equipment along with a software package for data interpretation, finite element modeling, and correlation of models to field data. The entire system produces a calibrated model of the load tested bridge for purposes of load rating. The system evaluated as part of this study was the Bridge Diagnostics, Inc. (BDI) Structural Testing System (STS). This paper documents a number of the efforts involved with the evaluation of the BDI system.