Finite Element Analysis of Fiber Reinforced Concrete Eccentric Anchorage Zone in Prestressed Girders

The anchorage zone, where the prestressing force is transmitted to the concrete, represents a critical component of prestressed girders. This research investigates the behavior of eccentric anchorage zones in prestressed girders constructed with fiber-reinforced concrete (FRC) using finite element analysis (FEA). The study specifically examines the impact of steel fiber volume ratio, bar size of the spiral in the local zone and bar size of the reinforcement in the general zone on the behavior of the anchorage zone.

A three-dimensional solid element model was created in ABAQUS software, employing non-linear analysis to replicate the structural behavior and strength characteristics of the eccentric anchorage zone when incorporating fiber-reinforced concrete. The analysis included different configurations of fiber volume ratios, the quantity of reinforcement in the local zone, and the quantity of reinforcement in the general zone.

The results indicate that using steel fibers with a volume ratio of 1%-1.5% can replace either spiral or tie reinforcement but cannot substitute the entire reinforcement system. Using 2% steel fibers results in an ultimate load increase of 30%-50%.

Specimens with fibers demonstrate more ductile failure modes. A spiral bar size of 20 mm increases ultimate load between 21% and 31%. Tie bar size of 10 mm increases ultimate load between 24% and 32%, with greater ductile behavior observed in specimens with tie reinforcement.