Final answer:
The question relates to engineering safety regulations during steel assembly. The exact weight limit for a bundle of joist bridging is not provided in the question and should be referenced from relevant local building codes or OSHA guidelines.
Step-by-step explanation:
The subject of this question is in the field of engineering, particularly related to the construction and assembly of steel structures. During steel assembly, there are strict safety regulations regarding the weight of materials to prevent overloading and ensure the safety of the workers and the structural integrity of the construction project. However, the question does not provide enough context to determine the exact weight limit for a bundle of joist bridging. Safety regulations such as these are typically set by local building codes or OSHA (Occupational Safety and Health Administration) guidelines in the United States. For an accurate answer, it is recommended to consult the specific regulations applicable to the jurisdiction of the construction site.