What are the main design considerations for temporary nose in incremental launching?

Temporary nose attached to superstructure during the launching process to reduce the cantilever moment on the superstructure, a temporary nose used in conjunction with central prestressing to reduce the tensile stresses on concrete to acceptable limits, the two main design consideration for temporary nose:

  • sagging moment: The maximum sagging moment that occurs at the point of joining temporary nose with the superstructure, this occurs when the launched structure is far from the pier, approximately 75% of the span length, this moment at the location of joining temporary nose and superstructure shall be considered in the design, the joining location will be weaker than the rest of the structure.