A day trip to Pittsburgh last Friday as a passenger allowed me time to watch the trucks pulling heavy-haul trailers. Taking a close look at the rear guards of trailers brought to light a fascinating subset of visible structure design. Each of the companies building dry freight trailers, refrigerated trailer (“reefers”) and platform trailers
has created a design to meet the requirements that a frame of certain height and width be placed at the rear end of the trailer. But what a variety. They are welded and bolted, steel and aluminum, sometimes with stiffener plates, sometimes with members around the outside edge, and always looking for simplicity and ease of manufacture.
This diversity is similar to the diversity of truss railroad bridges that went up in the United States as self-taught engineers applied their knowledge of load bearing structures and invented many types of truss before the Civil War. Now truss analysis programs are available for bridges. These indicate that many of these truss designs are very close to one another in capability.
EWI can help with design checks, and manufacturability assessments as companies look for an advantage is the structural design landscape.