Al,
No, you were on the money as always and I understood your post and the fact that there is no getting around Engineer approval when you have a root opening >3/4". I think actually that I was less clear than you. What I was trying to get at is that (and this is based on personal experience) because the root opening falls outside the limits of any of the Clause 3 prequalified joint details the EOR may insist that a qualified WPS for the application. To me, qualifying a WPS for the specific application is a less efficient approach than developing a written repair procedure, as you suggest.
Most of my experience of the last 15 years is on very large stiffened plate structures (offshore platforms) and gaps that exceed the WPS limits are an everyday occurrence, with the occasional very wide gap (i.e. greater than the 5.22.4.3 limit of 3/4" [19mm]). In recognition of this our approach is to prepare a written procedure for weld repair that includes numerous common situations (e.g. removal and reweld of weld defects, excessive gaps in CJP joints, change fillet to CJP due to excessive gap, etc). This is tied back into the QC system such that there is a method to quickly document these situations, get a dimensional control inspection, get Engineer approval when required, permit/require in-process welding inspection, specify additional NDT, and close it out when complete.
In my experience the 3/4" cut-off point for getting the Engineer involved is reasonable. If you have a root opening greater than this it is a very good idea to do some global dimensional checks and to further investigate to figure out what is going on - if not you could be painting yourself into a corner dimensionally.
Mankenberg
Hello Kip;
As is typically the case, we're on the same page once we get the details on the table.
The attached photo is an example of a repair we recently preformed on a box girder. It isn't as extreme as the case discussed in this post, but the methodology could be similar. The situation was that UT detected a problem in the root and several unacceptable indication in the body of the groove weld. The initial air carbon arc excavation resulted in a rather unimpressive groove. The root opening exceeded the maximum permitted by D1.1, so I wrote up a detailed repair procedure for the engineer to review and approve, which he did. The original weld was removed using a track torch so the resulting groove was something that we could work with. The backing bar was tacked to the member that was built up with all the tack welds within the groove. The tacks were then feathered by grinding and then the surfacing (build-up) welding began. The residual stresses of the build-up pulled the backing bar up tight to the opposite member, yet it was free to expand and contract during the build-up operation. Once the build-up was completed, it was dressed by grinding so that a relatively smooth groove face was produced. The assembly was allowed to cool to the minimum preheat temperature to allow the members to contract to their "home" positions and allwed the root to oen slightly. The weld was then completed in a typical manner using both stringers and weave beads. The weave beads were limited to 1/2 inch to reduce the chance of entrapping slag along the edges of the weld. The completed weld was allowed to cool and then it was checked with UT.
Best regards - Al
Al,
Nice work. This looks very much like how we do things on our projects, though we normally have two sided welds and as such use ceramic backing (unless we have a monster gap).
Kip
Topic American Welding Society Services / Technical Standards & Publications / D1.1 Correction of Root Openings
