New field-tested design framework improves bored pile foundations in weathered rock

Large-diameter bored piles are essential for major infrastructure, from elevated railways and long-span bridges to high-rise buildings. Yet when these piles extend into weak, weathered sedimentary rocks such as siltstone and sandstone, engineers face a persistent design challenge: the rock behaves neither like conventional soil nor like strong, intact rock. Instead, its load-bearing capacity depends heavily on in situ weathering, fracturing, and the interaction between the pile and the surroundi...