FCI Projects

Selected FCI Laser Metrology Research Projects

Bridge Virtual AssemblySteel Bridge FabricationBridge Metrology

Bridge Virtual Assembly System

TPF-5(226)

Transportation Pooled Fund Project TPF-5(226) was led by the Virginia Department of Transportation. Other project members included New York, Iowa, Texas, and the Federal Highway Administration.

Steel bridge fabrication procedures strive to deliver a bridge that fits together as-designed during erection. To minimize fit-up issues during erection, most fabricators employ a match-drilling process. Using this method, girder holes are drilled to fit with a standard pre-fabricated splice plate in order to ensure proper alignment. This method of fabrication is, however, labor and space intensive. Typically, holes can’t be machined into steel plates in the most efficient manner. Holes are now drilled in a fully fabricated girder with the web attached to the flanges, as opposed to placing holes in flat plates using more efficient drilling equipment. In spite of using current match-drilling procedures to guarantee alignment, there are still fit-up issues during erection. The goal of this project was to develop new tools and methods that improve current manufacturing processes and quality control (QC) during fabrication. These tools and methods provide much greater and more accurate information than current practices that rely on manual measurements. This project has developed and deployed a BRIDGE VIRTUAL ASSEMBLY SYSTEM (BRIDGE VAS) that improves current steel bridge fabrication processes. More reliable and more accurate information on what is being fabricated will produce a better quality end-product, benefiting both fabricators and bridge owners. The BRIDGE VAS eliminates the need to match-drill girders and has the potential to reduce fit-up issues during erection.
	Fuchs Consulting, Inc. has developed a BRIDGE VIRTUAL ASSEMBLY SYSTEM (BRIDGE VAS) that improves manufacturing processes and enhances quality control for steel bridge fabrication. The system replaces conventional match-drilling with virtual assembly methods, creating custom-designed splice plates. Vastly improved measurement and documentation of fabricated girders is possible with the system. This project report describes these improved measurements in detail and compares them to conventional measurement methods, including a detailed analysis of the accuracy limitations of current methods. An assessment of current fabrication processes was conducted and is presented. Based on this assessment, the measurement system was designed and tested; the design features and a system description are provided within this report. The system was deployed on a production bridge job, representing the first time entire lines of girders have been measured with such precision and accuracy and the first time virtual assembly has ever been demonstrated.

Instrumentation to Aid in Steel Bridge Fabrication

NCHRP-127

The goal of this project was to begin development of a complete laser measurement system that will eventually eliminate the shop assembly process of steel bridges and will provide a complete permanent record of the as-built condition of each girder. This system is built around an established commercial laser scanner and can provide features not found using any other commercial instrument or collection of instruments. This system measures girders in a fabrication shop, produces documentation, and can provide data to virtually assemble girders.

This NCHRP-IDEA project was a first step in creating a complete laser measurement system for steel bridge fabrication applications. To get a feel for various end-user perspectives, site visits were made to two steel bridge fabricators, which were High Steel Structures, Lancaster, PA, and Egger Steel Company, Sioux Falls, SD. Five weeks of testing and development work were conducted at the Federal Highway Administration (FHWA) Turner Fairbank Highway Research Center (TFHRC). This project testing culminated with one week of testing within an actual steel bridge fabricator. The FCI laser system was operated at High Steel Structures in Lancaster, PA. Here several straight and curved girders were measured along with other more complex geometry pieces. The completion of this project represents the first steps in developing a complete turn-key system for use in a fabrication shop.

Bridge Retrofit Laser System

NCHRP-153

This project has developed an advanced laser measurement system to accelerate the bridge retrofit process in order to reduce the time between identification of repair needs to resumption of service for a bridge. A unique laser system precisely measures sections of a bridge structure involved in a retrofit process. Measurements are processed to produce CAD design drawings of needed retrofit parts that can be automatically sent to a fabricator. The system uses a laser measurement system with features that cannot be found in other commercially available equipment. These features allow the system to provide data that is much more accurate than conventional methods and allows completely new types of information to be collected.

The bridge retrofit laser system is driven to a bridge site in a vehicle, quickly setup, and used to make measurements on the bridge. No special targets are needed and the structure does not need to be directly accessed. Very accurate measurements can be made over very large distances. The laser system will measure the exact dimensions and spatial location of bridge details, including splice hole locations based on measurements of bolt or rivet heads. Based on the physical laser measurements, CAD design drawings will be automatically produced. These drawings can be used by an engineering design firm and fabricator to rapidly produce retrofit parts. High accuracy measurements are essential for retrofit measurements (gusset plates, trusses) where precise location of splice holes is needed.