Method for the construction of elongated concrete structures such as bridges and the like

A method for erecting elongated structures, particularly multiple-span bridge superstructures of concrete, across an erection site comprising the steps of:

• establishing a construction zone at one end of the erection site;
• providing at said construction zone formwork means within which said structure may be formed in discrete sections;
• constructing said formwork means to include a formwork bottom and a stationary formwork remainder, with said formwork bottom being separable from said stationary remainder;
• forming said structure in said formwork means in discrete successive sections;
• joining each of said successively formed sections to a previously formed section and launching said sections in series from said construction zone to the opposite end of said erection site;
• providing means for moving said formwork bottom from said erection site in said launching direction together with each of said formed sections of said structure;
• performing said launching of said sections in series from said construction zone by moving said formwork bottom together with each section formed at said construction zone through one section length in the launching direction across said erection site while maintaining said formwork remainder stationary at said construction site;
• and subsequently separating said formwork bottom from said formed sections at a location spaced forwardly of said construction site after launching said sections therefrom.