If a big rig destroys an apartment building, should the tenants file together? What kind of damages can be recovered?

I am glad to hear that none of the tenants were injured.   More likely than not, the landlord will have  filed a claim against the trucking company's insurance carrier.  Because insurance companies have coverage limits, you may be dealing with a situation where multiple people are competing for the same money. 

The prior post by an out-of-state attorney gives a good summary of basic things to think about when deciding whether to hire the same attorney.  Note that in some situations the law will require consolidation of related cases/claims.  Additionally, plaintiffs have a legal obligation to "mitigate" damages (basically to keep them as low as reasonably possible).

You should note that the law imposes strict time limits on filing claims and you may lose valuable legal rights with the passage of time, so it makes sense to contact an attorney sooner rather than later.  This post is not legal advice and the specifics of your situation may mean a general answer does not apply.

The tenants can definitely sue for direct, out of pocket costs incurred owing to the building being rendered uninhabitable. For example, moving costs; any higher costs to rent at at the new location; higher commuting costs to get to work, during the time they're relocated; etc.. Being reimbursed for lost work is trickier, because of "proof" issues--showing that you had to take the time off and that it was directly linked to the event, or that you didn't take unnecessary time off. That's not to say you can't recover for it, just that it's less straightforward than recovering the direct, out-of-pocket expenses. (IMPORTANT! Keep your receipts, in order to prove the expenses.)

In terms of whether the tenants should file together or separately: the advantages of filing together is reducing costs by sharing them; the disadvantage is that you don't have sole control over the way the attorney handles the matter. A lot will depend upon the relationship between the tenants (do they like and trust each other?) and also on just how much money is at stake--if the amount each person is seeking to recover is less, it makes more sense to pool your resources.