What material is primarily used for a joint strip in containers?

The joint strip in containers is primarily made of steel or aluminum because these materials provide the necessary strength and durability to withstand the stresses and loads encountered during transportation. Steel and aluminum are also corrosion-resistant when treated, which enhances the longevity of the container, ensuring that it maintains its integrity throughout its operational life. The robust nature of these metals allows them to handle the torsion and impacts that might occur during handling and transit in intermodal operations.

Other options like wood may not be suitable due to its susceptibility to damage from weather and moisture, along with potential structural weaknesses. Plastic lacks the tensile strength required for heavy-duty applications, while fiberglass, although strong, does not provide the same level of durability or repairability as metal. The choice of steel or aluminum thus ensures that joint strips are functional and reliable components of intermodal container design.