According to ATM A153, what material must anchor bolts and nuts used for substation foundations be made of?

The correct choice is based on the need for durability and corrosion resistance in substation foundations. Hot-dipped galvanized materials are coated with a layer of zinc through a process that involves immersing them in molten zinc. This coating serves to protect the steel from environmental factors, including moisture and corrosion, which can significantly compromise the integrity of anchor bolts and nuts over time.

In the context of substation foundations, reliability is crucial, as these components are essential for ensuring the structural stability and safety of electrical equipment. Hot-dipped galvanized anchor bolts and nuts offer not only strength but also a long-lasting defense against rust and degradation, making them suitable for use in harsh outdoor environments.

Other materials like bronze and stainless steel, while they have their own benefits, may not provide the same combination of strength and corrosion resistance at an economical cost and may not meet specific standards set by relevant guidelines like ATM A153 in this case. Cold-rolled steel can be strong but lacks adequate protection against rust unless it is properly treated or coated, which does not align with the specific requirements outlined for substation installations.