When it comes to the definition of “constructive acceleration,” the case of Fraser Const. Co. v. U.S., 384 F.3d 1354 (Fed.Cir. 2004) is a cited case and contains an instructive definition, quoted below, for proving a constructive acceleration claim.
In a nutshell, a constructive acceleration claim is when the contractor incurs added costs for trying to complete the contract on time when it should be provided extensions of time to perform based on excusable delay (i.e., delay not caused by the contractor). These added costs could be bringing in additional supervision to manage the work, adding manpower to perform the work, working overtime, working weekends, adding more shift work, stacking trades, etc. However, just because a contractor claims they have been constructively accelerated does not make it so. The contractor has to actually ask for an extension of time based on an excusable delay and the owner either denied the extension or unreasonably sat on the request for an extension of time; thus, the contractor incurred significant costs to accelerate in order to finish the project on time because it was deprived of a requested time extension for excusable delay.