Measurement of residual force locked in open-ended pipe pile using fbg-based sensors

The residual forces locked in the piles significantly affect the interpretation of the pile load distributions. FBG-based sensors are used to studying residual forces in open-ended pipe piles, due to their high resolution and accuracy as well as excellent long-term stability. Two 13m-long full-size precast high-strength prestressed concrete (PHC) pipe piles were instrumented with FBG sensors and jacked in a building site in China. The field measurements show that the post-jacking residual forces increase with the penetration depth. The neutral plane of the residual force is located at 0.2 pile length above the pile toe, at which the direction of residual shear stress changes from downward to upward direction. The test results also indicate that an open-ended pile with a relative short soil plug behaviors assemble the open-ended pile. © 2012 ejge.