D-Type Big Span Steel Bridge/4.2m bridge deck net length/82.296m maximum ferr span length

D-bridge is the patent of Grert Wall.It was invited fom Gemany and has advantage in the long -span and big loading comparing to balley bridge.Thus, it can save cost of piers.
It panel chord is bigger than bailey bridge panel but the panel structure is simpler .All the components are bolted so the bridge can be used as a permanent bridge because of its small deflection. The components are inter changeable and repetitively used.This kind of bridge has various
structure changes to satisty diferent loading capacity.