Ultimate Moment of Unbounded Prestressed Concrete Pier

The calculation formula for the ultimate flexural capacity of the unbonded prestressed concrete bridge pier has been derived, the relationship between the ultimate bearing capacity and prestressing tendon area, the regular reinforcement area, the strength of concrete and other influence factors has been analyzed. The ultimate flexural capacity of the unbonded prestressed concrete bridge pier is studied based on the plastic-hinge method. Then the influence of different factors on the ultimate flexural capacity is analyzed. The results show that, the increase in the area of regular reinforcement and the strength of concrete can enhance the ultimate flexural capacity. Moreover, the ultimate bending moment increases first and then decreases, with the increasing of the prestressing tendon. Thus, the most effective method to increase the ultimate flexural capacity of prestressed concrete bridge pier is to increase regular reinforcement ratio, and to control the number of prestressing tendon simultaneously.