In the context of reinforcing bars, the standard protocol regarding tack welds is that they are prohibited unless specific authorization is provided by the engineer overseeing the project. This prohibition is based on several factors related to structural integrity and safety.
Tack welds are often discouraged because they can introduce unintended stresses or weaknesses in the rebar reinforcement, which is critical in ensuring the strength and performance of reinforced concrete structures. The concern is that the heat from welding can alter the metallurgical properties of the bars, potentially leading to failure under load conditions.
By requiring authorization from an engineer for any tack welds, it ensures that any deviations from standard practice are based on a thorough evaluation of the specific engineering requirements of the project. This protocol helps maintain safety and quality standards in construction practices related to reinforcing bars.