During the fabrication of steel bridges errors
occur. These errors need to be recognized and corrected properly and efficiently
according to each individual situation. To arrive at the best possible
solutions, engineers need not only knowledge of material and fabrication
specifications but also experience and good understanding of the practical
limitations faced by fabricators. This expertise is scattered and varies among
both individuals and DOTs. A database of corrective actions can provide guidance
to bridge engineers and improve engineers' confidence in non-textbook solutions
to unusual but not unique problems. When a sharable and well reasoned repair
database is used by several state DOTs within a geographical region, the
database can lead to standardized solution procedures that would expedite bridge
fabrication and would be expected to reduce fabrication costs, which could
result in a reduction of costs passed back to the DOTs.
The the AASHTO/NSBA Steel Bridge Collaboration Task
Group 5 is assembling such a repair database in the context of a FHWA pooled
fund research project at the University of Kansas. The repair database software,
Fabrication error Indexed eXamples and Solutions (FIXS), examines fabrication
errors of steel bridge members when detected in the plant and recommends
corrective action. FIXS provides solutions and examples to steel bridge
fabrication errors with graphical and instructive explanations based on both
rule-based and case-based reasoning. This
information: the type of error, the reasoning behind the trial solution, and the
outcome of the solution, will be uploaded to the FIXS database so that when the
same or similar type error occurs in the future, engineers can benefit from or
improve upon previous solutions. The
objective of the current project is to make easily available to multiple DOTs.
The anticipated delivery mechanism is the World Wide Web.
This tutorial document is being produced as part of the FIXS project. The intent is to provide a short written document introducing bridge engineers to issues necessary for good resolution of fabrication error situations. This tutorial provides not only recommendations of fixes to consider but also examples of options to avoid. Resolution of fabrication errors is an engineering task where similar problem situations are encountered on a semi-regular basis by a DOT organization but infrequently by an individual engineer. This tutorial is intended to help inform engineers of ways DOTs and fabricators could make mutually beneficial changes to prevent the occurrence and/or ease the resolution of common fabrication errors.
This document contains the information presented in the “Generic
Solutions” menu in the actual FIXS software along with pertinent references
available to engineers. The major
categories of errors in the “Generic Solutions”: Mislocated Holes, hole restoration (sometimes referred to as
plug welds), Errors associated with stiffeners, Overheating, Nicks and Gouges,
and Surface Lamination.