Both BS8110 and BS5400 Pt.4 mandate the use of nominal reinforcement in columns to ensure structural integrity and prevent brittle failure. However, this requirement might not be universally applicable to pile design.
Firstly, piles are typically embedded underground, minimizing their exposure to unexpected loads that could compromise their stability. Secondly, shear failure in piles, even under severe collision scenarios, is generally not considered critical to the overall structure, as the load can often be redistributed to other piles. Additionally, the likelihood of pile buckling due to fire is low since fires rarely occur underground.
However, the recommendation to include nominal reinforcement for seismic resistance in piles is valid. Earthquakes can generate significant lateral forces that can induce bending and shear stresses in piles. Nominal reinforcement helps to enhance the pile’s ductility and energy absorption capacity, making it more resilient to seismic events. As suggested by J P Tyson (1995), this reinforcement is particularly crucial in regions with high seismic activity.
In conclusion, while the necessity of nominal reinforcement in piles may be debatable for certain scenarios, its inclusion for seismic resistance is strongly justified, especially in earthquake-prone areas. Engineers should carefully assess the specific project conditions and potential risks to make informed decisions regarding the appropriate reinforcement strategy for pile design.