Structural Performance of Slotted Reinforced Concrete Bridge Pier

Abstract

Bridges are among the most important structures for human civilization. Bridge safety is therefore an ongoing concern of engineers. Scouring of river beds due to blocking of downstream current by the bridge pier is one of the main causes of bridge failure. A bridge pier with a slot facilitates the passage of water downstream and thereby creates less vorticity, which in turn results in the reduction of scour formation. The introduction of a slot in any compression member like a column (or a bridge pier in the present case) is likely to be questioned for its structural safety. Thus, the present work investigated the comprehensive structural behavior of bridge piers with slots in them. Such bridge piers were structurally evolved in the present work based on the basic design philosophy, and were numerically modeled in ABAQUS 2019. Multiple sizes of slots are investigated considering a wider scenario. Different performance measures like natural frequency, Von Mises stress, and strain were evaluated to explore the fundamental structural behavior. The Von Mises stress [considering the pier as a three-dimensional (3D) continuum] was taken into account for the typical design check between capacity and demand at the material level. Although the introduction of slots raises the concern for structural performance of the bridge pier, it was taken into account that there is an insignificant degradation (in terms of Von Mises stress measure as well as Cauchy’s stresses) in the structural performance of the slotted pier in comparison to the pier without slot. Reinforcement was proposed for the slotted pier considering induced stress pattern under reasonable loading scenario. Mode shapes of the slotted pier system were evaluated to understand its dynamic structural behavior. In addition, the overall capacity of the slotted pier system was evaluated on the basis of critical buckling load and axial load-carrying capacity against each of the different slot sizes in the pier, which may help to determine the trade-off between hydraulic requirements versus scouring and structural capacity/safety.