Population Demographics of Suspension Bridges

A plot showing the number of bridges for each category of suspension bridge constructed for every year starting with the year 1990 is shown in Fig. 15.24. This plot clearly indicates that the classical catenary suspension bridge reached its zenith during the latter half of the 1920’s. It also shows the impact that the introduction of stayed bridges, starting in 1955, has had on the catenary suspension bridge. The decreasing population of the catenary suspension bridge results from the limited number of sites requiring spans in excess of 2,000 ft.
The growth and popularity of the cable-stay bridge in the last half of the 20th century has been phenomenal. The cable-stay bridge has largely supplanted the classical catenary suspension bridge, for spans up to approximately 2,000 ft. The catenary suspension bridge is still dominant for spans exceeding the 2,000 ft limit, although the cable-stayed bridge is beginning to make inroads.