Question
What is the sucker deck principle for changeable depth bridge decks?

Answer
For a variable depth bridge deck, depth of continuous multi-span bridge deck is greater than before in pier supports and this absorbs sagging moments in a mid-span with consequent increase in hogging moments in pier supports. As a consequence, mid-span depth is able to be significantly concentrated due to reduction in sagging moment. In core, this sucker deck principle is applied in places where headroom requirement is of great concern. Moreover, in terms of structural presentation, sucker decks are effective in dropping dead loads than voided block of equivalent uniform depth for span length between 20 to 40meter. In necessities of aesthetics point of view, public be likely to value the structural form of arches and curved soffit somewhat than boring consistent deck alignment. Reference is completed to Brian Pritchard in 1992.