Abstract:
This paper presents a stability assessment of the steel pipe piles that are proposed to support a deadman anchor beam of a bulkhead wall. Finite element stability analyses indicate the necessity to anchor a bulkhead wall that has a 16-foot wall height and a 4-foot water differential head on the back. The steel pipe piles that were installed to support shoring system during the construction are proposed as the potential anchor piles for the bulkhead wall. The distance between the anchor pile and bulkhead wall is relatively short with respect to the wall embedment, and therefore the lateral capacities of the anchor piles are considered compromised due to the potential interaction of their passive soil zones with the active soil wedges of the bulkhead wall. The reduced lateral resistance capacity of the anchor pile is determined by applying the Coulomb wedge method on the truncated soil passive zone between the wall and pile. The required tieback force for the bulkhead wall is determined from the conventional retaining wall stability analysis with at-rest earth pressures, and they are verified with the finite element model analysis. The conventional retaining wall stability approach with the truncated passive resistance is then used to check the stability and performance of the anchor piles using the concept of solder piles. The bending demand of the anchor pile is also verified by a LPILE model analysis, in which the pile resistance reduction factor (like group reduction factor) pM is determined based on the truncated soil wedge. Using the proposed design approach, the lateral capacities of the pipe piles with different spacing to the bulkhead wall are evaluated.