Remove column & add beam & columns

A few questions/comments:
[ul]
[li]Is the existing beam continuous over the column being removed?[/li]
[li]Are you trying to get the existing beam to work compositely with the new?[/li]
[li]For these types of design, you need to consider how they're going to shore up the roof while removing column/installing beam - do you have something in mind for this? You would need the ends of the joists shored up on each side of the beam, while leaving room to get the new steel in place and connected[/li]
[li]Sometimes the shoring can be just as costly as the rest of the work. A method I've used successfully in the past the eliminate the shoring: instead of using a single beam, put a new beam on each side of the existing column. You can install new columns, install the new beams on each side of the new/existing column, connect the beams to the new/existing columns and you can now remove the existing post below the new beams. Granted this method might be difficult given your spans, I've done this with shorter spans using a channel on each side of the columns[/li]
[/ul]

Is the existing beam continuous over the column being removed?
Exising beams are simple span
Are you trying to get the existing beam to work compositely with the new?
No - just figuring existing beams as dead load for now, but will analyze further to check assumptions and look for unexpected reactions, etc
For these types of design, you need to consider how they're going to shore up the roof while removing column/installing beam - do you have something in mind for this? You would need the ends of the joists shored up on each side of the beam, while leaving room to get the new steel in place and connected I was thinking we could shore each side of the existing beam and have clearance to install new beam from below. A contractor looked this with me a couple years ago and seemed good with it.
Sometimes the shoring can be just as costly as the rest of the work. A method I've used successfully in the past the eliminate the shoring: instead of using a single beam, put a new beam on each side of the existing column. You can install new columns, install the new beams on each side of the new/existing column, connect the beams to the new/existing columns and you can now remove the existing post below the new beams. Granted this method might be difficult given your spans, I've done this with shorter spans using a channel on each side of the columns[/i] I'll have to study that procedure a few minutes to make sure I follow you
Thanks for your input.

Jport - Modifying the bar joists will be labor intensive (expensive), I prefer not modifying existing members unless essential (to avoid unforeseen unintended consequences).

Instead, I would use a (likely heavier) W27, or what ever size is necessary, to support a point load at it's center with an an acceptable unbraced length of 24'.
This also avoids possible complications of how W18s share load with a W27. Keep things simple.

jport -
take a look at these two threads which are similar to what you are looking at.

thread507-431504

thread507-419492



Check out Eng-Tips Forum's Policies here:
faq731-376

I have had a similar situation recently and did similar to what SlideRuleEra is suggesting:



We specified some angle kickers to help brace the new beam top flange.

This is an amalgamation of some of the fine ideas suggested above with one nifty feature: LTB is precluded.

Thanks everybody! Lots of great info!
I still need to get dimensions, sizes, etc on the existing framing, but I can see some combination of these ideas working for me.