forward launching pre-cast girders

huangyhg

forward launching pre-cast girders
can anybody help me with info about forward launching truss or nose for a span of 95' and a box girder of 72 tons? any other ideas welcomed.
details: rr bridge 8 spans, 5 girders per span, i would like to erect them from the top (deep canyon underneath).
i don`t known really what do you expetc in this forum, but your problem is really complex. you have to design a steel structure that support each piece of concrete during the launching, is a  special design, where you have to know velocity of the wind, earthquake, dead load, impact, friction, stop forve and others. luck
                    
the book
theory and design of bridges
petros p. xanthakos
wiley interscience, new york 1994
in chapter 8 treats segmental construction (span per span as well) and has ample bibliography from where to expand study.