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.
The formal boundaries for the City of Waltham (see map below) encompass a land area of 12.73 sq. miles and a water area of 1.02 sq. miles. Middlesex County is in the Eastern time zone (GMT -5). The elevation is 66 feet.