Instrumentation of a Smart Composite Bridge
Martha Jannette Molander
Abstract
A bridge made completely of fiber reinforced polymer composite material and instrumented with extrinsic Fabry-Perot interferometer fiber optic sensors has been installed on the Missouri University of Science and Technology campus. The bridge was built to the AASHTO H20 standard so that it could be used as a demonstration for industry and so that it could be used for teaching two smart structures courses. This project was a joint effort between the university and industry. A National Science Foundation grant funded most of the research, and the primary industry partner was Composite Products, Inc. Several test articles were also constructed as part of the design process. This thesis describes the design process and testing of the smart composite bridge instrumented with fiber optic sensors with emphasis on the fiber optic instrumentation.
The project began with a four-layer beam. This four-layer beam was instrumented with two fiber optic sensors and tested to failure. Next, an I-beam was built. This I-beam was also instrumented with two fiber optic sensors and tested to failure. Three mini-bridges were built for demonstration purposes. All three mini-bridges were instrumented with fiber optic sensors, and data from one of the tests is shown in this thesis. Finally, Missouri's first all composite bridge was built. This smart composite bridge had twenty-four fiber optic sensors embedded in it as it was manufactured at the Lemay Center for Composite Technology in St. Louis, Missouri.
The primary objectives of this research were to experiment with using fiber optic sensors in a field environment and to test the reliability of the data that come from these sensors. Fourteen of the 24 sensors embedded in the campus bridge survived the installation process, a survival rate of fifty-eight percent. The data from the various tests showed good correlation with other sensors and with theoretical predictions.
Evaluation of an Innovative FRP Bridge Deck System
Prakash Kumar
Abstract
Application of fiber reinforced polymer (FRP) pultruded sections for civil engineering applications in infrastructure is rapidly increasing. Composite members may potentially provide more durable replacements for steel and concrete in primary and secondary bridge structures, but significant amount of work still needs to be done before the application of composites in infrastructure applications can become a routine. This research work contributes towards achieving that goal.
An extensive experimental and analytical program was carried out to obtain and compare properties (stiffness, strength, failure modes) of 76 mm (3 in.) square hollow pultruded glass FRP tubes and their assemblies which were used in the fabrication of an all-composite bridge deck designed for H-20 truckloads as specified by the American Association of State Highway and Transportation Officials (AASHTO). All the coupons were tested in three- and four-point bending. Experimental results show excellent linear elastic flexural and shear behavior up to failure. A quarter portion of the full-sized bridge deck was then tested for its structural performance under design and fatigue loading and also for ultimate load capacity to evaluate the bridge response under H-20 loading. The characteristics of the full-sized bridge deck were determined by analyzing the tests performed on relatively smaller sections of the same design.
Based on results of the present research, all-composite bridge decks made of pultruded glass and carbon FRP tubes is judged to be a suitable replacement for bridges made of conventional materials.
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Instrumentation and Manufacture of a Smart Composite Bridge for Short-span Applications
8th Annual International Symposium on Smart Structures and Materials:
Smart Systems for Bridges, Structures, and Highways ,
Proc. SPIE 4330, 4-8 March 2001, Newport Beach, CA
Authors:
Steve E. Watkins, John F. Unser
Antonio Nanni, K. Chandrashekhara, and Abdeldjelil Belarbi
Abstract
A smart composite bridge is described that features an all-composite design and an integral sensor network. This short-span structure is nine meters in length and is designed for an AASHTO H20 highway load rating. The prototype bridge, the first full-composite bridge in Missouri, was installed on the Missouri University of Science and Technology campus as a field laboratory for smart structures courses and a demonstration of composite technology. It was designed, analyzed, and manufactured as a cooperative product development among university, industry, and government partners. It has a modular construction based on a pultruded 76-mm-square composite tube. The cross section of the overall structural element is an I-beam formed by seven layers of bonded tubes. The top and bottom layers are carbon/vinyl-ester tubes for strength and the other layers are glass/vinyl-ester tubes for economy. Extrinsic Fabry-Perot interferometric fiber-optic sensors were embedded throughout to measure temperature, flexure strain, and shear strain. Also, radio-frequency identification tags were co-located with sensors to aid in determining load placement during field tests. This paper gives an overview of the project emphasizing the smart instrumentation. In particular, the installation of the integral sensors, the plan for the sensor network, and preliminary strain results for vehicle loading are discussed.
Keywords: Smart Structures, Composite Bridges, Fiber Optic Sensors, Health Monitoring
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Adaptable All-Composite Bridge Concept
Composites 2000, Composites Fabricators Association, Las Vegas, Nevada, 26-30 Sept. 2000
Authors:
John Unser
Composite Products Inc.
St. Louis, Missouri 63125
Prakash Kumar, K. Chandrashekhara,
Antonio Nanni, and Steve E. Watkins
University of Missouri â€-œ Rolla
Rolla, Missouri 65409
Abstract
Composite Products Inc. (CPI) in conjunction with the University of Missouri â€-œ Rolla (Missouri S&T) designed and built an all-composite bridge that was installed at the Missouri S&T campus. The bridge spanned 30 feet and was 9 feet wide. The bridge was designed to AASHTO H20 load rating. Missouri S&T has conducted extensive Finite Element Analysis (FEA) and testing on the bridge. The building block of the bridge is a pultruded 3 inches square tube. The tubes was bonded and screwed together using adhesive to form eight layers. The first and seventh layers are carbon reinforced with inside and outside layers of ±45 stitched fiberglass mat. The matrix was vinyl ester resin with flame retardant additives. The carbon tubes were produced by CPI at Lemay Center for Composite Technology (LCCT). The remaining glass reinforced tubes were manufactured by Bedford Reinforced Plastics. CPI assembled the bridge at LCCT and was transported in one piece to Missouri S&T. The bridge has fiber optic sensors built into the structure. The paper gives an overview of the project summarizing the FEA; component testing; static and fatigue testing of bridge main structural element; and installation.