Welded Beam Splice

[INBCPE]

I have a W14 roof beam that I need to partially remove and replace in order to swap out a conveyor (about 8 ft of a 25 ft beam). The W14's span from one W24 girder to the next (50' apart), with one column support in the middle. We can brace the adjacent W14's and frame the opening, support the steel surrounding the opening (only a 12ft ceiling), open the roof to expose the beam, cut the 8 ft section out, remove the conveyor, splice in the replacement section of beam, and close up the roof. The splice will be welded in accordance with AISC (full pen, qualified D1.1 welder, NDT), and we're adding splice plates on either side of the web and under the bottom flange. In a nut shell, at the end of the job the beam will be back in position, but with two welded splices about 8 feet apart.

All the references I see are for bolted splices, except for the AISC manual, and very little detail is provided there other than showing where the backing has to be. The proposed splices are in areas of moment. Is the splice I proposed above consistent with anything out there? My only other alternative is replace the whole beam, but then I have to rip open the roof across the entire span.

Any help or direction is appreciated.

 

[warrenw]

I'm suprised that no one has replied to you post by now so I will give it a shot.
If you are welding the W14 with full penetration butt welds for the full cross-section of the W14, then the beam splice should be as strong as the beam it self. Adding the web splice plates and bottom flange plate will increase the capacity at the splice.
But if the W14 is not fully butt welded and the loads at the splice location are only carried by the splice plates, then the splice plates must have the same cross-sectional properties as the W14 (same section modulus and shear area, etc). In other words, if you take a cut thru the W14 at any point along the span the cross-section should be equal or greater than the original W14.

 

[dicksewerrat]

Why do you HAVE to cut the beam? Can't you move the conveyor 3 feet and miss the beam? Or take the conveyor apart and out the door? This just seems a bit radical.

 

[INBCPE]

Update:

To dicksewerrat, the equipment we were replacing was two stories high, with a steel and concrete mezzanine at the second story. Moving it over to clear the beams would involve a lot of demolition of the existing mezzanine. Also, the equipment would never have cleared the existing beams.

To warrenw, we designed splice plates, had them fabricated, and installed them in accordance with AISC and AWS D1.1. It worked out fine. Another contractor came up with an alternate solution several years ago, involving a gaping hole in the roof for the full length of the beam span, and replacing everything (roof, decking, beams, etc) that got ripped out. Our solution ended up being half the price and took only a third the time.