Leftwow:
I am not trying to pick on you personally, but if you don’t start asking some meaningful questions, with enough basic info. to start a meaningful exchange, you really won’t get much real help. It never ceases to amaze me that you OP’ers. don’t get the concept that we can’t see what you are looking at from here, and we really can’t read your mind, just because you post no relevant design info. Reread your own posts so far, and assume that you don’t know anything about your design problem, which is our situation here. Imagine the hundreds of arrangements that any of us could conjure up, which would fit what you’ve told us. Then, say and think, “wow...” what a stupid question, instead of “wow...” they don’t seem to understand that it is not a regular crane rail beam. Of course, you still haven’t given us much meaningful design info., either. It took about 13 posts to learn, “It is a fixed telescoping boom crane. On top of a structure.” That’s a bunch of wasted time on the part of people trying to help you, as they play your guessing game.
What does the supporting structure look like? Where are the possible support points for your structure, and how do you plan to frame your structure? Dimensions, existing member sizes and orientations, etc. etc. are all important in an experienced engineer’s first impression of your problem. Does the crane weigh 265k or is this the load it can lift at some radius at any position on the compass? Does the crane start from its ring beam/bearing circle and on up; and then your structure supports this bearing ring, and takes the load out to the existing structure below?
Lomarandil (24FEB17, 22:00) is right on the money. And, I would add to his comments that sometimes in a situation like this it is easier/better to start with fabricated/welded structural elements, box beams, plate girders with heavy webs, from plates, bars, etc. which really allow you to put the meat where it is needed. Many times rolled sections are not the best starting point, although many Structural Engineers seem to think this is so.
You have to lay out this kinda stuff in some meaningful form, so others understand what the heck you are talking about. And, you should proof read your posts with this in mind. You may not have definite answers to some of these questions, I certainly don’t have all the answers. But, you have to give us a meaningful starting point with sufficient basic design info. or we’ll still be guessing at post #200. And, from this standpoint, “I am looking to design a beam that can withstand 265 kips of shear force. In this situation, what would you guys consider, and what is your opinion on the best section to resist a high shear force?” is a sophomoric question.
