Steel Building Expansion Joint - Is it required at first level composite slab over crawl space

[MJC6125]

I have a one story steel building with a large L-shaped footprint. We are planing to do an expansion joint at the junction between the two legs of the L. The first/ground level of the structure is a composite slab on steel beams over a crawl space due to expansive soils not allowing for a slab-on-grade.

Does the expansion joint need to be present at the 1st level framing/slabs or is it only required at the roof framing and exterior walls? I was thinking you wouldn't need it for 1st level because that framing and slab should be temperature controlled all year long. I don't think it's that different to a slab-on-grade, and I assume expansion joints aren't usually put in those in a building (I could be wrong on that?).

If you believe it is required, are expansion joints also required in foundations? This project has a grade beam on drilled piers foundation, so an expansion joint in that would need to be done via two lines of drilled piers with separated grade beams.

There are some steps in the slab throughout the building (not necessarily aligned with the building expansion joint) where the slabs will not directly attach to each other, so I feel like that should help with potential slab cracking from too large of a building footprint.

 

[HTURKAK]

If you post the structural plan showing the dimensions, bracing locations, if the crawl space vented or not, ambient temperature for winter and summer .. we can discuss ..

The expansion joints should not be required in foundations .

Remember, provide more info to get better responds.

 

[r13]

First you need to determine whether an expansion joint is necessary by considerations on building geometry, material properties, heat source, duration, and frequency and rate of heat intensity changes. Unnecessary joint can cause problems than none. If it is necessary for the roof, then it seems would require the same in the floor slab, otherwise tear could occur in the vertical elements that cross the joint, even the floor itself does not expand. By carefully select the type of expansion joint and proper design, the impact on foundation should be minimal, if any.

 

[dik]

At a transition in building shape, I'd put one in 'all the way up', except at the foundation as noted.


Dik