Flexural strength of prestressed reinforced concrete piles using high-strength material

If concrete bridge systems are constructed in conditions such as very soft soil that can experience soil liquefaction due to a severe earthquake, it is difficult to prevent yielding of the pile foundation. In this study prestressed reinforced concrete pile using high-strength material to increase the pile's flexural capacity is developed. The main structural characteristics of the developed pile are that (1) the neutral axis is constantly near the centroidal axis of the pile, even if longitudinal reinforcements are yielding due to flexural moment, because the pile has a high axial compression force induced by the prestressing steel bars. This means that the concrete in the compression region can contribute to increasing the flexural strength of the pile; and (2) using carbon fiber sheets to prevent the spalling of the cover concrete can contribute to increasing the flexural strength of the pile. The results of the bending test show that the proposed prestressed reinforced concrete pile with carbon fiber sheets and infilling concrete has a higher flexural capacity than that of a pile without these sheets and infilling concrete, and the pile did not exhibit brittle behavior.