Natwerk Designs

What leg length of weld do i need for universal beam splice?

I've got to design the splice detail for a steel universal beam (i-beam). It needs to be spliced similar to fig.c in this picture http://www.mundysteel.co.uk/images/builderimg.jpg It consists of end plates welded to the ends of the sections and then bolted together. I need to know how much of the beam needs to be welded to the plate. Is it just along the top and bottom of the flange or aroung the inside too. Then i need to know what size weld i need to use. I have found this table http://www.corusconstruction.com/en/design_and_innovation/structural_design/fasteners/fillet_welds/ I'm assuming the longitudinal capacity is the one were considering here. But how do i apply these values to the problem? The beam is going to be installed horizontally so there will be a bending moment about the top flange trying to pull apart the bottom flange. How do i work out the resistance of the weld? Maybe someone could just tell me what leg length and where to weld. beam is 254x146x37 Please only answer if you have experience and know what your talking about or can direct me to a resource that is trustworthy. If the splice fails people could get hurt so its important. Thanks I meant transverse capacity not longitudinal capacity above sorry.

Public Comments

1. When an I-beam is put in bending (with a downward load), the top of the beam is in tension and the bottom is in compression. The center of the beam is mostly in shear. If you have the ends of two I-beams butted against each other, and you need to weld them into a single I-beam, the highest-stress areas will be along the top and bottom edge, so these should definitely be welded (especially the top edge, which is in tension). However, you should also consider that the weakest point on a weld is where the weld begins or ends (since there's a small concave radius at this point, creating a stress concentration). Now, since the welded splice is going to be by far the weakest point on the beam, you should go for the highest moment of inertia you can, meaning welding along the entire cross-sectional perimeter of the beam. If you must omit a section, omit the center of the beam (the vertical segment), since the stress is the smallest here, and it makes the least contribution to the moment of inertia. I strongly recommend welding the entire perimeter of the horizontal sections of the I-beam, like this: --------------------------- |------------ -------------| ------------- ------------- |--------------------------|
2. good evening, i am a fabricator/welder, whenever i am fabricating anything structural the i always 'fully weld' all the base plates / end plates etc, fully weld is the answer, it not as though its a huge beam thats going to take ages to weld...