Testing Using Bi-directional Method for Bored Pile on Clay Soil in Indonesia

Sei Alalak Curved Cable Stayed Bridge located at Banjarmasin, South Kalimantan is a replacement bridge located next to the previous bridge. Bored pile was chosen as its foundation with 1.8 m diameter and 70 m length design for 1350-ton ultimate capacity. The soil consists of medium to stiff clay along the pile length. Bi-directional load test was chosen over conventional load test considering the potentially damage in pile structure when using reaction system and cost when using the kentledge system. Vibrating wire strain gauge as its instrumentation installed at various level to get load transfer, skin friction distribution as well as t-z and q-z along the shaft. Result showed most of capacity borne by its shaft resistance under small displacement while the end bearing needs more displacement to fully mobilized.