Why build a cable-stayed viaduct or “suspension bridge” over land (not water)?
First of all, the viaduct proposed is not a suspension bridge. The superstructure (or deck) of a suspension bridge is supported by vertical cables that are, then, sustained by a large arched main cable hanging from the top of the pylons. The superstructure of a cable-stayed bridge or viaduct is supported by diagonal cables in direct tension to the pylons. Cable-stayed structures are becoming popular in today’s bridge construction, because they are one of the most cost-effective methods of building long elevated spans, in terms of time of construction and use of materials. It has also the advantage of being more aesthetically pleasing than other types of bridges. A second reason for choosing a cable-stayed structure to replace the aging Gardiner Expressway, is to prevent enormous disruptions to existing train and automobile traffic. The pylons supporting the superstructure will have an A-shape, so its foundations straddle rail traffic in the corridor. The existing expressway functions n
