splicing a single span steel beam

[v2]

Please, consider the following conditions.

As part of a mezzanine construction in an existing building I need a searies of W14X159 47.0'long beams on the 3rd floor.

A one splice per beam at 1/4 of its length would be acceptable by the contractor.

given the size of this section, what whould you prefer more a welded splice detail or the all bolted one.keep in mind that the top flange cannot be bolted and the splicing plate cannot be on top of the top flange so there will be no interference with the composite steel deck.

Thank you.

 

[dlew]

V2,

I would use a welded splice because if the top flange can not be bolted, it will have to be welded any way.

The moment at the splice is relatively large (75% of the maximum moment). I would specify a non-destructive inspection (dye-penetration or magnetic particle) on those welds.

I assume the contractor wants the splice to be able to move the beam into position inside the existing building.
I would try to locate the splice as close to one support as possible. If, per example, the splice is located at 1/8 point of the span, the moment at the splice could be reduced to 44% of the maximum.

Hope this will help

AEF

 

[evelrod]

Full penetration welding is perfectly acceptable for your requirements, HOWEVER----Magnaflux or dye penetrant testing just will not do the job. Welds on this type of splice in the location you state and at any significant load should be (at least) UT'd. The other methods are fine in controlled conditions but are not accurate enough for your requirements. Contact you inspector and give him your requirements. He will know how to handle the UT.


Rod

 

[v2]

Thank you both.

I understand from Evelrod that if I used a full penetration weld all around then I will not need splicing plates any more. I think I can make the connection with splicing plates and 1/4" fillet welds all around.
but I just wonder which one would be more economical, since this connection is going to be used, and typical, on a large number of repetitive beams.

 

[evelrod]

If the splices are to be made in the field it is up to you to determine which method is cost effective. If the splices are to be done in the shop during fabrication then, by all means, use full penetration welds suitably inspected and tested.


Rod

 

If you have a lot of them, can you center your 1/4 pieces over the support and use a "drop-in" beam concept every other span to eliminate some of your moment connections with simple shear connections needed for erection anyways? (4 spans would eliminate 4 moment connections, 3 spans would elimnate 2) Maybe this would also size down your beam slightly with the shorter drop in beam span and cantiliver over support for backspan beams??

 

[LPPE]

Why not use a bolted splice connection? The plate and the bolts should be hidden in the slab, no? You can also weld shear studs to the flange plate, just use a shorter stud. Even if you dont use studs on the splice area, your composite section should not be significantly affected.
A bolted splice connection is much easier and less costly to erect in the field than a full pen splice. Also, a bolted connection doesnt need to be UT'd.