A Systematic Approach for Determining Vertical Pile Depth of Embedment in Cohensionless Soils to Withstand Lateral Barge Train Impact Loads
Technical Report,01 Apr 2014,31 Dec 2014
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS VICKSBURG United States
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Pile-founded flexible lock approach walls are typically constructed with impact beams simply supported on pile bents or by using an impact-deck supported by groups of clustered piles. Cast-in-drilled-hole CIDH reinforced concrete RC piles have seen recent widespread use as a cost-effective method of transferring superstructure loads to the foundation soil e.g., cohesionless soils, like sand. The primary design load for lock approach walls are dynamic barge train impacts on a beam or deck which occur as the barge train aligns itself for entrance to the lock. These bents and decks are supported tens of feet ft above the mudline and barge impacts occur at the beam or deck level i.e., lateral loading at approximately the top of the pile. Because of this lateral loading applied at the top of the piles, vertical pile groups must be designed to exhibit long-pile behavior e.g., nominal change of deflection at the pile cap for a given load as the pile-tip depth-of-embedment increases. These design loads introduce substantial moments for the vertical piles at a short distance below the mudline. A pushover analysis of vertical-pile clusters can be performed to determine the energy absorption of the structure and the peak loads that cause the piles to hinge a short distance below the mudline, leading to collapse. This peak load is used to compare different pile depth-of-embedment procedures for long-pile behavior, and leads to the development of a new systematic procedure for defining this depth. Reducing the length of piles will result in a cost savings for Corps projects, especially for in-the-wet construction.
- Structural Engineering and Building Technology
- Civil Engineering