How Long Does a Static Load Test Take in Total?
A static load test verifies pile load capacity by applying real load to the pile head in increments and measuring settlement until the full test load is reached. The test method follows ASTM D1143/D1143M-20e1 and DPT 1251 of the Department of Public Works and Town & Country Planning (referenced through the DPT piling standard DPT 1106-64, clause 6.1).
Unlike a PDA test, which can test several piles a day, a static test ties up a single pile for several days, because a large amount of kentledge has to be hauled in and installed, and settlement has to stabilize at every load step.
Three figures you can plan with right away:
If you count from the day the bored pile is cast, add about 21–28 days for the concrete to cure, so the total time from casting to report is usually around 5–7 weeks. It can be shorter if you book the test while the concrete is curing. All figures are planning ranges; the actual duration depends on the test load, reaction system, project specification and site conditions.
Why Does a Static Load Test Take Longer Than a PDA Test?
A static load test takes longer than a PDA test because of the nature of the method itself, not because of crew delays. There are 3 main reasons.
- The reaction must exceed the test load — the test usually goes to 2–3 times the design load (depending on each project's specification). For example, a pile designed for 100 t needs kentledge or reaction piles able to resist more than 200–250 t. Hauling, stacking and leveling a load of this size takes days. Read more about reaction systems in Kentledge vs reaction piles: which to choose
- Settlement must stabilize at every load step — the Maintained Load method of ASTM D1143 Procedure B requires each load step to be held until the settlement rate is no more than 0.25 mm/hr, and the maximum test load to be held for 12 hours, or 24 hours if settlement has not stabilized, to capture the time-dependent settlement (creep) of clay
- The load must be released in steps while measuring rebound — after the maximum load, the load is released step by step while measuring rebound to determine the residual settlement. In addition, many Thai specifications require more than one test cycle
By comparison, PDA uses only a few hammer blows per pile, so about 5–10 piles can be tested per day if the piles are in the same area. See the in-depth comparison in Dynamic vs Static Load Test: which is better?
What Are the Steps of a Static Load Test, from Booking to Report?
A static load test has 6 main steps: booking, concrete curing, installing the reaction system, loading per the Loading Schedule, dismantling, and issuing the certified report. Steps 1 and 2 can run in parallel, while steps 3–5 are the actual time on site.
The diagram below lays out all 6 steps with the time frame for each. Step 4 (incremental loading) is the heart of the test. The box at the bottom combines steps 3–5 into the on-site time per pile of about 3–7 days, together with the factors that make it run longer.
Step 1: Booking, Confirming Data and Designing the Test Setup (1–3 Working Days)
The first step is to provide the pile type and size, the design load, the test load required by the specification (e.g. 200% or 250%), the number of piles and the site location. The engineering team then designs an adequate reaction system, calculates the amount of kentledge, and selects the main beams, jack and load cell to suit the test load, before issuing a quotation and scheduling the site date. This step usually takes 1–3 working days.
Step 2: Waiting for Concrete Strength and Soil Setup (Bored Piles ~21–28 Days)
The pile must be strong enough to carry a test load of 2–3 times the design load without damage, so bored piles usually wait about 21–28 days for the concrete to reach its design strength. Precast driven piles already have hardened factory concrete, but must wait for the soil around the pile to recover (soil setup) as specified by the engineer. See details in At what concrete age can a pile be tested?
Note that if the reaction system uses bored reaction piles, those reaction piles must also wait for their concrete to cure, so plan to cast the reaction piles together with the test pile. This step can run in parallel with booking; the two do not have to happen one after the other.
Step 3: Site Preparation and Installing the Reaction System (1–3 Days)
On the first site day, the crew trims the pile head flat and square, places the kentledge supports (concrete pads or timber/steel cribbing) at the distance from the test pile required by the standard, then uses a crane to lift concrete blocks or other kentledge onto the main beams.
Next, a hydraulic jack with a load cell is installed on the pile head, and at least 2–4 settlement gauges (dial gauges or LVDTs) are mounted on an independent reference beam. For a Kentledge system of several hundred tonnes, or where site access is narrow, this step can take up to 3 days. See the pile head preparation checklist in Preparing the pile head before testing
Step 4: Loading per the Loading Schedule (1–3 Days)
This step is the heart of the test. The engineer increases the load in steps of about 25% of the design load and holds each step until settlement stabilizes (rate no more than 0.25 mm/hr) before recording readings. At the maximum test load, the load is held for 12–24 hours, then released step by step while measuring rebound.
If the specification calls for 2 cycles (Cycle 1 to 100% then unload, Cycle 2 to 200% then unload), this step usually takes 2–3 consecutive days, with the crew taking readings around the clock. A test pile loaded in 3 cycles to 250–300% may take about 3–4 days.
Step 5: Unloading and Dismantling (~1 Day)
After the final unloading step and once rebound has been fully recorded, the crew removes the kentledge, takes down the beams and equipment, and hands the area back to the contractor. This generally takes about 1 day.
Step 6: Analysis and Certified Report (A Few Working Days)
This step takes a few working days after the final unloading step. The engineer plots the load-settlement curve, evaluates the total settlement, residual settlement and ultimate capacity using the Davisson criterion, and concludes whether the pile meets the specification criteria.
The report is signed and certified by a civil engineer licensed by the Council of Engineers Thailand (COE) and can be submitted with building permit applications to the relevant authorities. See how to read the curve in How to interpret static load test results
Loading Schedule: How Many Steps, How Long Are Holds, and How Many Cycles?
The Loading Schedule sets how much load is added at each step, how long each step is held, and how the load is released. The on-site duration depends directly on this schedule.
Roughly, a Quick Test (where the specification allows it) takes about 2–4 hours of loading, a Maintained Test about 24–48 hours, and a multi-cycle specification about 2–4 days. The table below compares the 4 most common formats.
← Scroll to see the full table →
| Loading method | Load steps / hold time | Approx. loading time | Used when |
|---|---|---|---|
| Maintained Test (ASTM D1143 Procedure B) | Steps of 25% of the design load, held until settlement rate ≤ 0.25 mm/hr (max. 2 hrs/step) · at 200%, hold 12 hrs, or 24 hrs if not yet stable · unload in 25% steps, held 1 hr each | ~24–48 hrs | The standard method most widely used for general buildings |
| Thai 2-cycle specification (multi-cycle Maintained Load) | Cycle 1: 0 → 100% → 0 · Cycle 2: 0 → 200% → 0 · hold at 200% usually specified as 24 hrs | ~2–3 days | Working piles under most project specifications |
| Test pile 250–300% (3 cycles or to failure) | Adds a 3rd cycle to 250–300% of the design load, or loads the pile to failure to determine ultimate capacity | ~3–4 days | Test piles before production piling starts |
| Quick Test (ASTM D1143 Procedure A) | Steps of ~5% of the expected failure load, each held 4–15 minutes, up to the test load or failure | ~2–4 hrs | Where the specification allows it and ultimate capacity is needed quickly, with no focus on creep behavior |
The number of cycles, the test load percentage and the hold times must follow the project specification and the design engineer. SPN tests to the Loading Schedule set by the project and records the actual procedure used in every report so that it can be audited later. Read more about test loads for each type of pile in Test Pile vs Working Pile: how many times the load to test?
How Long Does Each Step of a Static Load Test Take?
In short: booking 1–3 working days, bored pile concrete curing ~21–28 days, installing the reaction system 1–3 days, loading 1–3 days, dismantling ~1 day, and issuing the certified report within a few working days.
← Scroll to see the full table →
| Step | What to do | Approx. time |
|---|---|---|
| 1. Booking + system design | Confirm the test load, choose the reaction system, quotation, scheduling | 1–3 workdays |
| 2. Concrete curing / soil setup | Bored piles wait for design strength · driven piles wait for soil recovery (in parallel with item 1) | ~21–28 days (bored piles) |
| 3. Install the reaction system | Trim the pile head, place supports, stack kentledge, install jack, load cell and gauges | 1–3 days |
| 4. Loading per the Loading Schedule | Increase the load in steps, hold at maximum load 12–24 hrs, unload in steps (1–3 cycles) | 1–3 days |
| 5. Dismantling | Remove kentledge, take down beams, hand back the area | ~1 day |
| 6. Analysis + certified report | Load-settlement curve, Davisson criterion, signed by a licensed engineer (COE) | Few workdays |
Total on-site time (steps 3–5) is about 3–7 days per pile. If several piles are tested on the same project, the crew can move the kentledge set straight to the next pile, which shortens the average time per pile — ask for a timeline specific to your job when you request a quote.
What Makes a Static Load Test Run Longer Than Planned?
Based on SPN's field experience, static load test timelines usually run over for 5 main reasons:
- Settlement does not stabilize within 12 hours — common in Bangkok soft clay; the load must be held for the full 24 hours per ASTM D1143 Procedure B
- Soft ground under the kentledge — the Kentledge supports settle or tilt during the test, and work has to stop for releveling. Compacting the ground before mobilization helps a great deal
- Site access and crane — narrow roads, mud or rain can stop several hundred tonnes of kentledge from being delivered on schedule
- Reaction piles not yet cured — with a Reaction Pile system using bored piles, you must also wait for the reaction pile concrete, not just the test pile
- Pile settles beyond the limit during the test — testing must stop so the design engineer can decide before continuing. For the next steps, see Static Load Test failed: what to do
What Information Do You Need to Book a Static Load Test?
Have the 7 items below ready when you contact us to book, so the reaction system can be designed and the schedule assessed in one go.
- Pile type, size and length (driven or bored pile, diameter)
- Design load and the test load required by the specification (e.g. 200% / 250%)
- The Loading Schedule required by the specification (number of cycles, hold times), if any
- Number of piles to test and their locations on the layout
- Conditions around the pile (clear space for kentledge, access for cranes and trucks)
- Concrete casting date or driving completion date, to calculate when the pile is ready for testing
- Site location (province/district) for estimating travel and mobilization costs
Static load test fees are about THB 50,000–150,000+ per pile, depending on the test load and reaction system. This price excludes travel and equipment mobilization costs, which are charged extra according to the site distance.
See the factors that affect the price in Pile testing prices 2026, or the overview of SPN's pile testing services
Summary
A static load test takes about 3–7 days on site per pile, because the reaction must exceed the test load and every load step must be held until settlement stabilizes, particularly the maximum load, which is held for 12–24 hours per ASTM D1143. If the pile is ready, the total time from booking to a certified report is usually around 2–3 weeks. For a freshly cast bored pile, add another 21–28 days for the concrete to cure.
The most effective way to keep to the timeline is to send the complete specification and pile data at booking, compact the ground where the kentledge will sit, and plan to cast the reaction piles together with the test pile.