Span-by-span erection is the most common construction method for precast segmental bridges, and the underslung gantries are the simplest, least expensive, and often most efficient self-launching machines for span-by-span erection.
Span-by-Span Erection of Precast Segmental Bridges: Underslung Self-Launching Gantries provides exhaustive coverage of the topic. It explores loads, kinematics, support and launch systems, and performance and productivity of these machines, and it also discusses span assembly, the stiffness interactions to consider for the design of bridge piers and superstructures, and staged application of post-tensioning to avoid decompression of epoxy joints and the risk of brittle span failure.
The eManual provides exhaustive coverage of the topic for bridge owners, designers and constructors interested in span-by-span construction of precast segmental bridges with underslung self-launching gantries. Other monographs of the Bridge Engineering eManuals project discuss segment fabrication, the span assembly operations common to all families of erection gantries and lifting frames, and the other types of self-launching gantries used for span-by-span and balanced cantilever construction.