A pile is generally considered "set" if the downward movement does not exceed with a minimum holding time of 30 seconds .
Specialist builders must have detailed procedures, method statements, and instructions for the application of appropriate regulations, codes of practice, standards, specifications, guidance documents, and customer requirements. Jacked piles (steel, concrete) require a pile jacking machine with accessories.
GEOSS defines termination not by a single number but by a three-part rule:
Additionally, all jacked piling works must be supervised by a registered under BCA’s IES/ACES scheme, with a copy of the GEOSS checklist submitted to QPS (Qualified Person Supervision) daily. A pile is generally considered "set" if the
Yet, jacking piles is not merely “pushing steel into the ground.” Without a rigorous framework, the process can lead to ground heave, pile damage, or refusal at premature depths. Enter the . Specifically, the GEOSS Good Practice for Installation of Jacked Foundation Piles provides the definitive local benchmark for engineers and contractors. This article dissects that good practice, translating code into actionable field wisdom for the Singaporean context.
Use pre-boring at the pile point to ease penetration and limit ground movement in dense soil. Active Monitoring:
: Piles terminating unexpectedly early due to localized hard strata or boulders may not have sufficient deep friction or end-bearing capabilities. Designers must evaluate if these short elements jeopardize overall group foundation integrity. GEOSS defines termination not by a single number
Do not attempt to achieve refusal by suddenly increasing hydraulic pressure. That cracks piles.
A critical aspect of GeoSS practice is the standardisation of pile termination to ensure geotechnical capacity: Jacking Force: The required jacking force ( cap P sub j
: Standard practice often involves Ultimate Load Tests (ULT) loaded to 3x WL and Working Load Tests (WLT) loaded to 2x WL to verify stiff settlement behavior. Specifically, the GEOSS Good Practice for Installation of
Jacked piling uses pre-formed elements (like prestressed concrete spun piles, precast RC piles, or H-steel piles) pressed into the ground via a hydraulic system weighted by counterweight dead loads. This article breaks down the technical requirements, termination criteria, and structural challenges of installing jacked foundation piles according to the GeoSS Guideline and Singapore Building and Construction Authority (BCA) frameworks. Core Mechanics and Machine Capacities
: Piling machines must undergo a regular maintenance regime by a dedicated team, with daily, monthly, and yearly checklists to ensure equipment is always in good condition. Compliance and Regulatory Framework
Under performance‑based pile design (joint BCA/IES/ACES/GeoSS circular 2022), BCA allows the flexibility for QP(D) to submit more than one set of pile design and pile design parameters in a single submission for approval for projects adopting bored pile foundation. After obtaining written approval from the CBC of the adopted design and pile design parameters, installation of working piles can commence on site. Under the performance‑based pile design, pile optimisation can be carried out on site without the need to wait for the approval to the amendment plan.
In Singapore’s marine clay, a jacked pile gains capacity over time (thixotropic setup). GEOSS provides a time-dependent factor: