Analysis And Design Calculation On Stress Of Unbonded Tendons In Prestressed Concrete Multi-span Continuous Structures

Ultimate stress increment is a hotspot problem in theory of unbonded partially prestressed concrete structure,however,according to design critera and the art of the state on this issue around the world,it is still not considered in reason that ultimate stress of unbonded tendons in prestressed concrete multi-span continuous structures varies with load cases.This paper demonstrates ultimate stress increment of unbonded tendons can be composed of approximate elastic deformation along the elements and local plastic deformation by nonlinear analysis on the unbonded partially prestressed concrete continuous structures. Referring to the rule of ultimate stress increment of unbonded tendons at every load case,a regression formula of ultimate stress increment of unbonded tendons based on elastic-perfectly plastic model has been presented for engineers to calculate ultimate stresses of unbonded tendons in prestressed concrete multi-span continuous structures.