edge distance ties too tight

[delagina]

i have a small concrete block on top of a steel beam. there's an equipment saddle with bolts on top of the concrete. the bolts will be connected to the steel beam as shown in pic.

my main concern is the concrete - 700mmx200mm. i want to put ties around the bolts but it seems too tight.

what is the minimum rebar you will put in this concrete to prevent cracking? say forces are negligible

 

[delagina]

i was thinking of doing this instead. but do i really need ties

 

[TehMightyEngineer]

It's hard to tell from the pictures but the first thing I notice is the edge distance (edge of flange to edge of bolt) for the bolts is very, very small. I doubt they can take much load or even be fabricated like that.

As for the concrete block; you mention that this is an equipment saddle. What loads does it have? Gravity I assume but will the equipment try to move the beam/concrete laterally? If the loads are small (and you fix the bolt issue) I imagine that this may work. I don't think you would need ties either way but that depends entirely on the code you have to follow and the loads applied. I saw you put in a stiffener, was this due to web crippling calculations or just from engineering judgement?

Maine EIT, Civil/Structural. Going to take the 1st part of the 16-hour SE test in October, wish me luck!

 

[Teguci]

If you want to prevent cracking, don't do this. Replace the concrete with steel stands ( you could use the same beam size to make (2)-6" deep stands for each set of anchor bolts. If you need to fill the voids, use grout or install studs and fill with concrete.