What is a common approach in dealing with Utility caused delays? Is the Contractor entitled to monetary compensation or only a time extension?

Is a Change Order required for Force Account?

Note that the Contract Administrator is the interpreter of the Contract Documents, and the judge both parties to the Contract (GC 3.6.1). Refer to General Conditions regarding Extra Work and Change Orders.

Whose role is it to prepare payment certificates?

The Contract Administrator.

"Quality Assurance and Quality Control Testing" video - Contract Consideration Series

There is a certain amount of confusion shown in forum and class questions about the difference between Quality Assurance and Quality Control. This video brings some clarity to this topic as well as discussing testing and retesting options.