This had a profound impact. The amount of steel needed to build suspension bridges could be hundreds of tons less than required by previous design practice. Less steel greatly reduced the cost of a bridge. By the late 1920s and into the 1930s great long-span suspension bridges were being built across the country.
Waltham, Massachusetts. Waltham (/ËwÉËlËÎ¸Ã¦m/) is a city in Middlesex County, Massachusetts, United States, and was an early center for the labor movement as well as a major contributor to the American Industrial Revolution.
Middlesex County. 1  City of Waltham websites: 2  Waltham online resources: 3  Waltham information from state agencies:  Regional information from state 1  agencies: Information specific to Waltham can also be found within the following comprehensive listings:  Other Waltham community websites: