What document determines the type of high-strength bolts used for a project?

The correct choice is the engineer of record's project drawings. These drawings are critical as they provide the detailed specifications for the structural design of a project, including the type of materials to be used. Specifically, they outline the requirements for high-strength bolts, such as the grade, diameter, and the configuration of bolt connections required for structural integrity.

These drawings are directly developed in accordance with industry standards and design codes, which ensure that the selected bolts meet the necessary mechanical properties and performance criteria for their intended application. They are tailored to the specific needs of the project and take into consideration factors like load requirements, environmental conditions, and other design considerations relevant to the project.

In contrast, inspection reports detail the compliance of materials and construction methods with the specifications but do not define the materials themselves. On-site observations pertain to the conditions and practices found during the construction phase but lack the authority to dictate material specifications. Manufacturing guidelines are important for understanding how bolts should be produced but do not establish what is used in a particular project. Therefore, the engineer of record's project drawings serve as the definitive source for determining the type of high-strength bolts employed in a given construction project.