ANALYSES OF THE EXTREME AXIAL SHORTENING OF THE PARTIAL PRESTRESSED CONCRETE CONTINUOUS BEAM BRIDGE

Extreme axial shortening of a continuous beam bridge always occurs in both construction and working stages, and it may cause loss in serviceability, durability, or safety of bridge. This paper takes a partial prestressed concrete (PPC) continuous beam bridge as an example and carries out an analytical study on the phenomenon of shortening, especially for some interrelated parameters' effect of this phenomenon. The studied interrelated parameters are dead load, living load, shrinkage, creep, temperature change. A finite element analytical model is developed and the effect of reinforcing steel bars is considered in the study. The variety of axial shortening is traced and a quantitative analysis of the axial deflection is made. The results indicate that the creep is the most significant factor for the beam extreme axial shortening, which contributes to 40% above of the total value. Through the analytical study on this case, a study method is illustrated and the principle of this kind of bridges' extreme axial shortening is uncovered.