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I am looking at a W18x50 beam. ASD design loads at the ends are 9.5k shear and +/- 5.4k axial load (there is no diaphragm, so horizontal bracing is provided and this leads to some axial loading). For fatigue, the end connections see a range of 6.6k shear.

SWComposites, I appreciate you wanting to help with this, but this is more of a structural steel question. When modeling a steel structure, connections are usually defined as simple or moment resisting. There are various standard types of simple shear connections (shear tabs, double clip...

Going back to straub46's reply, I'm concerned about the beams that support the runways. BTW, this is a structure inside a building, not the building itself. Previous systems had fully restrained beam to column connections to provide lateral stiffness and lateral force resistance. The system is...

It's an underhung crane system, so bearing supports are not an option. Similar previous systems have been installed with runways hung from beams that have full moment end connections (shear tabs and either flange plates or field welded flanges). There are reasons in this particular situation...

Thanks Brian. The steel solutions center is a good idea. This is a beam that supports runways for an underhung automated crane system, and cranes will pass by every 3 minutes, so definitely a fatigue situation.

I have a basic question. My understanding is that one of the ways that simple shear connections accommodate rotations is through localize yielding, for example at bolt holes. My understanding is also that cyclic loading that is sufficient in magnitude to cause yielding will cause crack growth...

There have been some posts asking for more detail about the falling part, the conveyor etc. The conveyor carries finished weldments in a major ag/construction manufacturing facility. As such, there is a wide variety of shapes, sizes, weights, dimensions etc. The conveyor is a overhead power &...

Thanks bones206. One question - the deflection formula is based on elastic behavior over the entire cross section, so it is only valid to initial yield, right? I am thinking to do an analysis similar to what you linked except using S instead of Z. The end result doesn't change much.

Tomfh - can you elaborate on how to calculate the internal work, especially past yield? For a W10x49 spanning 16 ft. modeled as simply supported, I calculate an elastic spring rate of 53494 lb./in., a deflection at yield of 1.063 in., so energy absorbed to initial yield = 0.5 k x² = 0.5*(53494...

I am trying to figure out how to design a beam to absorb the impact from a falling object. A conveyor carries 13,000 lb. parts over an industrial enclosure that we are building. The customer wants the roof beams to protect the people inside if a part falls from the conveyor. The fall distance is...

Thanks to everyone for your replies. @retired13, replacement with a wide flange would be the right thing to do. In my original statement I simplified the situation a little bit. What they are actually proposing is weld repair of the cracked tubes before adding the cap plate ... which is another...

I need help finding published examples of fatigue checks for built up members. We have an HSS16x8x3/8" serving as a crane runway. Using HSS in this application was a terrible idea ... no need to tell me that. The cranes run on polyurethane coated wheels which are not as wide as the flat surface...

... and just to clarify, our equipment is installed inside of a new building. The owner applied for a building permit for the building, and the building inspector seems to be applying the special inspections required for the building to the equipment that is contained inside the building.

Thanks JLNJ and JStephen. JLNJ said field erected items get special inspections unless waived by the AHJ. Maybe we just have not run up against this requirement before, but are you saying that everytime and everywhere that structural steel is field erected, a 3rd party inspector must be hired?

I am trying to understand when 3rd party inspections are required by IBC. 1705.2.1 says that "special inspections ... shall be in accordance with the quality assurance inspection requirements of AISC 360." AISC 360 defines quality control being provided by the fabricator and erector, while...

Thanks dhengr, I follow your suggestion now. In all of this, keep in mind that I am a mechanical engineer, so if I say something that is ignorant in the structural world, have mercy. The hoist manufacturer traditionally has used a design of tube columns, tube beams, and tube knee braces, all...

dhengr: I really appreciate your time. The tube beam is HSS12x6x1/4" and the knee brace is HSS6x6x1/4". The knee brace is at 45 degrees. The beam projects 22" from the column. The column flange width is 11.25". Tube to column weld is 5/16" fillet all around, knee to column weld is 3/16"...

Thanks dhengr. Would it be possible for you to roughly sketch what you are suggesting? I am struggling to follow the description.

Just found this in AISC Design Guide 7: Fatigue provisions have a 95 percent reliability factor (two standard deviations below mean curve of test data) for a given stress range, and expected life condition. Thus, it is reasonable to expect that 5 percent of similar details can experience...

Thanks HotRod10 - that's exactly what I have been wrestling with. If I use the assumption that the weld carries both components of the load, then I need to reinforce the connection in the field. Two options I am considering are to build up the existing welds or add plates on the sides of knee...