What inspection task is common to all allowable methods of pretensioning high-strength bolts?

The correct choice emphasizes the importance of inspecting the condition and markings of high-strength bolts, which is a critical step in ensuring their performance and reliability when pretensioned. All acceptable methods of pretensioning high-strength bolts require that the bolts are in good condition and properly marked to meet specific standards. This inspection helps to ascertain that the bolts are not damaged and that they are the correct type for the application, particularly in terms of grade and tensile strength.

The markings on the bolts not only indicate their specifications but also provide essential information about compliance with industry standards, which is vital for structural integrity. Thus, inspections of bolt conditions and markings are universally applicable across all methods of pretensioning.

The other options do not pertain to commonality across all pretensioning methods. Checking the bolt color can be relevant in some contexts but is not a standardized practice for pretensioning checks. Measurement of bolt length may be important, but the requirement can vary based on the specific application or connection design, making it less universally applicable than condition and marking inspections. Overall weight assessment is not typically a standard inspection task for pretensioned bolt methods. Therefore, focusing on the condition and markings of the bolts provides the necessary assurance that they will function correctly under load.