Pipe pile to plate connection on bridge cap beam 1

[foreng]

When connecting a pipe pile to an embedded plate on a cap beam of a bridge pier, which type of weld works best? fillet or a groove weld with a steel backing ring?

I was told it is difficult to get a proper weld because of the difficulty in getting all the pile tops level enough to get each plate flush with the pile. Any thoughts?

 

[ishvaaag]

Having the pile entirely through the cap as your exposition seems to indicate is something many wouldn't want to see. You may be wanting to add shearhead items to the embedded part.

Respect buildability, certainly a field situation won't help to get perfect levels even with sawing someway upon a works' slab on the ground.

Respect behaviour, a complete penetration weld properly mechanized is likely to behave better in any instance movement and fatigue (even if short term cycle) may be of interest. Remember how we break wires in just a dozen of large plastic deformation cycles. Full penetration welds lack the prebuilt extant fisure angle welds leave in the unfused thickness, and so are better at fatigue.

 

[foreng]

see attached drawing, I've seen both types of welds used. I noted on drawing 2 they didn't specify complete penetration, just wondering if it should be considered?

 

[gtaw]

The second sketch allows for some error in the cut off length of the piling. If the piling is cut too short the root opening is greater. If the piling is cut too long, the root opening will be smaller. This will give the field workers some latitude in trying to cut the pilings to the exact length.

The first sketch requires the workers to cut each of the pilings to the exact length and perfectly square to obtain the proper fit for welding. Remember, if the root opening is more than 1.6 mm, the fillet weld size has to be increased. The increased fillet size increases the volume of weld metal required and the time it takes to weld by the square of the weld leg. In other words, the volume of weld in a 13 mm is four times that required to deposit a 6.4 mm weld. If the root opening exceeds 5 mm, the base metal has to be repaired by depositing weld on the edge to close the root opening. Costly process that takes time to complete.

The groove weld, with backing is probably the best way to proceed. However, the groove shown appears to be a square groove, very difficult in the best of circumstances. A bevel groove with a 45 degree bevel would be easier to weld.

Best regards - Al

 

[foreng]

Thanks gtaw,

Very helpful

 

[hokie66]

Gtaw's advice is good. Not only is the second option better for site welding, you get a stronger connection with the groove weld.