Historic Iron and Steel Riveted Bridges: two presentations in 2025 by Vern Mesler and Nan Jackson, scheduled in Grand Rapids and Marshall, Michigan:
- Grand Rapids
- September 11, 2025, 7:00pm
- Ryerson Auditorium, Grand Rapids Public Library 111 Library N.E., Grand Rapids, Michigan
- Marshall Michigan
- September 22, 2025, 6:30-7:30
- Marshall District Library 124 W. Green Street, Marshall, Michigan
Books abound from both the eighteenth and nineteenth centuries that document the engineering perspective on riveted bridges and the development of their designs. During this same period, advances in wrought iron and steel making processes, metal fabrication methods, and machinery were also made, but these accomplishments are less evident in the written record. A historic riveted metal truss bridge is a craftsman’s record. If one reads it carefully, much can be learned from the bridge itself about the manufacturing processes used in its construction.
Walk along a historic metal bridge and you will likely see rivets. Steel and wrought iron rivets, thousands of rivets, each one driven by craftsmen operating either a pneumatic or hydraulic riveter in the fabrication shop or a field pneumatic hammer on the construction site.
Bridge components were fabricated with wrought iron, historic steel, and cast iron. These materials were made from iron ore smelted in a blast furnace, some rolled into structural shapes by Carnegie, Cambria, and Bethlehem historic mills, their signatures embossed in the metal as “mill marks.”
Michigan’s historic bridges have a connection with the early production of steel, as iron ore from Michigan’s Upper Peninsula was used in the original converter to produce large quantities of steel. Bessemer, Michigan, was named after the converter’s inventor, Henry Bessemer.
Lengthy diagonals of wrought iron or steel bar-stock stretch from top to bottom of the truss bridge; at each end of these diagonal bars is a forge-welded or upset eye and through the eye a bridge chord pin with recessed nut. These bridge chord pins and recessed nuts (known as Lomas nuts) are historically significant features of a historic metal truss bridge.
An engineer views a bridge for its design and abstract concepts; it is the craftsmen with fire, hammer, and skills learned from past master craftsmen that give the engineer’s concepts shape.
