By Mike Forbes Feature Bridge Inspection Update The changes included in the most recent version of AWS D1.5 are outlined Nondestructive evaluation (NDE) of aging bridge structures is used to assist in determining the current condition of the structure and is a great tool for eliciting recommendations regarding making repairs and in calculating the remaining life of the bridge —Fig. 1. Some of the more common types of nondestructive methods that are performed are ultrasonic testing, magnetic particle examination, and dye penetrant inspections. The type of NDE used is dependent on what part of the structure needs evaluation. Ultrasonic examination can be utilized to monitor and detect cracking in the completely penetrated welded areas as well as to examine the pins on a pin and hanger bridge — Fig. 2. Magnetic particle examination is utilized on fillet welds, as well as a variety of components such as eye bars (Figs. 3, 4), to detect any 22 Inspection Trends / April 2011 discontinuities that may arise. Dye penetrant inspection is commonly used in monitoring the repair process of bridge welding. Bridge inspections are carried out according to the requirements of AWS D1.5, Bridge Welding Code. Following is an outline of the changes that were made to the most recent edition of the code. Changes to AWS D1.5 AWS D1.5, Bridge Welding Code, covers the welding requirements for AASHTO welded highway bridges utilizing carbon and low-alloy construction steels. The 2010 revised edition supersedes the 2008 edition. This revision was undertaken as a direct response to a need to establish a common welding specification for the fabrication of steel highway bridges by welding. This revision is also the direct result of recognition by highway and transportation officials in all 50 states, District of Columbia, and Puerto Rico, which make up AASHTO, of a need for a single document that can address the issues of public safety with structural integrity in bridge fabrication. The changes incorporated in D1.5M/D1.5:2010, Bridge Welding Code, include the following: Electroslag Welding Changes • The requirements for electroslag welding (ESW) were separated from those for electrogas welding (EGW). • The ESW requirements now include the narrow gap improved electroslag welding process (ESW-NG). • Commentary for the new Annex I was added for electrode consumables. • A new Annex J was added to address the guidelines for alternative ESW process. • New information (Annex Q) was added as a guide for the use of ESWNG. Matching Filler Metal Tables • Tables 4.1 and 4.2 have been consolidated into one table 4.1. Clause 5 — Qualification • The qualification methods of 5.12 and 5.13 were consolidated under the newly revised 5.12 with modified and improved language that details maximum heat input and maximum/minimum heat input production qualification. • Provisions were added to address qualification of hybrid joints (e.g., Fig. 1 — Bridges undergo nondestructive examinations in order to assess their current condition and to help predict their useful lifespan.
Inspection Trends - April 2011 - Spring
To see the actual publication please follow the link above