Quick Question: Skewed T-joints The obtuse angle side

Date 11-17-2015 18:16

Hey All,

When it coes to skewed T-joints in D1.1, it's clear to see in 2.4.3.2 an obtuse angle greater than 100° is to be stated in the contract documents. But if the effective throat is set to something like 5mm in the contract documents for a 140° , that really doesn't leave a lot of connecting weld material if the joining members are two rectangles.

Specifically Figure 3.11 shows only one figure of this type of joint (where the angle is between 60° and 30°), D/

Am I to assume, that this obtuse angle with square cut joining members leave an area open enough that one should have full fusion on the obtuse angle side?

Clear as mud right?

Thanks!

Attachment: Fillet.png - Here is the print in question...currently being reviewed by myself and the engineer. (31k)

By welderbrent (*****)

Date 11-17-2015 23:22

As you read the associated clauses through Clause 2 you will find that it is the engineer/detailer's responsibility to detail the joint in question when it is past the point of being a fillet weld, 80-100°, and show what they want. Reason: this is closer to a PJP but is only so if they designate it so. Either way, they need to show a depth of bevel, depth of penetration (we all understand the associated Z-loss with certain processes and joint configurations...RIGHT???), and any extra re-enforcement as these will normally be welded flush with the surface of the plate unless added weld is specified.

Now, at some point it is almost impossible to weld on the back side. Then the engineer must decide if they want a PJP with added re-enforcement or a CJP with backing as how would you get in and do a back or backing weld? It will be dependent upon the stresses and their calculations.

Take note, if they don't specify then they need to be careful how they do draw the joint or CJP is implied and that is often missed until the TPI comes along and says, 'What's this? You can't do that.' Then the arguments start. Read Clause 2.3.5.3 carefully.

Often times the weld will actually turn out to be a CJP in practice but not in engineering calcs or inspection. If you were to UT or do a practice plate that could be cut and macro-etched you would see complete penetration a good portion of the weld length.

The key to the question in your last paragraph is the disclaimer: should. No, it SHOULD not unless the engineer detailed and called it a CJP. But, it MAY when looked at thoroughly.

So, what density is the mud at now?

He Is In Control, Have a Great Day, Brent