Static Load Test for bore piles: A complete guide!

Static load test for bore piles:

A static load test is a process that assesses a structure or foundation’s capacity to support a specific load. So, the structure or foundation is subjected to a static load throughout the test, and the deformation and strain are tracked to assess how the object responds to the stress.

During a static load test, we’ll use hydraulic jacks, weights, or other load application equipment to apply the load slowly and gradually to the pile . However, depending on the design specifications and rules, we’ll frequently apply the load in small increments.

Meanwhile, we’ll use sensors like strain gauges, tilt meters, or displacement transducers to perform the static load test. So, these will help us to track the deformation and strain of the structure or foundation.

Consequently, we’ll hold the load for a predetermined amount of time, usually several hours or days. The responsible engineer will record the data at regular intervals.

After reaching the maximum load, we’ll reduce the load gradually. By this time, we’ll study the deformation and strain until the structure or foundation reaches its initial state.

We’ll assess the performance of the pile based on the data we gathered during the static load test. Then we’ll compare the data to the design specifications, codes, and standards. It’ll ensure us if the pile is safe and can achieve the essential performance requirements.

so, to confirm the design presumptions and guarantee the safety and performance of the structure, we frequently perform static load tests in the construction of bridges, buildings, and other structures.

The objective of static load test

1.Determination of the ultimate and allowable bearing capacity.

2.Determining the settlement under ultimate and working load.

3.Proof of acceptability.

so, you already understand that Today we’ll discuss the static load test following the ASTM standard (ASTM D1143) practice by the Kentledge method using concrete block as counter weight and applying load onto the pile by a hydraulic jack (fitted with a single pump and single pressure gauge) acting on pile against a Kentledge

so, We’ll use the load onto the pile as a maintained load (ML) test, while increasing and sustaining the load for a certain period as defined by the code.

Previously we’ve done discussing about the High strain Dynamic load test for piles,let’s start today’s discussion on static load tests for piles.

Proof Load for static load test

Firstly, We’ll consider the proof load as 2.0 times of design load, and we’ll apply it onto the pile in increments, and we will maintain each increment for a certain period as mentioned in ASTM D 1143/ According to the contract document.

General Procedure for static load test

Then the labors will trim the Piles head smooth, leveled and finished with rich cement mortar to set the bearing plate under the hydraulic jack. 

Step by step procedure for static load test
Fig: Work Flow chart for bore pile static load test

In brief, we call the loading platform as the Kentledge, comprising steel I-beams as the spreader beam, main beam, rocker beam etc and concrete blocks as the counterweight. However, We’ll rest the Kentledge on two temporary concrete blocks wall on two sides of the test pile. Moreover, The contractors will use the dead weight of I-beams and Concrete to react to the applied load. In addition to the weight of Kentledge, they’ll add about 10% of the test load with the counterweight to avoid the tilting of Kentledge.

Section A-A for the kentlage setup of static load test
(Sec A-A)
Top view of block layout for static load test as counterweight
Block layout as counterweight for bore pile static load test

Girder Calculation of kentlage setup for static load test


Test Pile Ø =  1000 mm

Test Load, P = 700 MT

Test Load, P = 6,864 Kn

Weight of Kentledge, P*1.2= 8236

Size of Kentledge:

Length of main beam, L =12 m

Length of short beam, B =12 m

So, Design of Main Girder Load on main girder- w= P/L =572.000  kN/m 

Following this, Maximum cantilever moment, M = w*L2/8 =10296.000 kN-m

Property of Main Girder:


Total Depth= 1750 mm =175 Cm

Width=600 mm = 60 Cm

Moment of Inertia of each plate girder, I = 3398733 cm^4 (dimensions are provided in attached drawing)

Distance of extreme fibre, C = (175-10)/2= 82 cm

Sectional Modulus, Z= I/C =(3398733/82)= 41447.96 cm^3

Yield strength, fy=345 N/mm^2

Required Total Sectional Modulus, Z=M/f=(10296.000*1000*100/34500) cm^3 =29843.478 cm^3

Number of main girder required= (Required Total Sectional Modulus/Sectional Modulus) = 0.720

Providing 2 number plate girder as main girder,

Forming steel, FS=2/0.720 = 2.778

Property of Secondary Girder, 600 mm

Total Depth, D = 600mm


Flange Thickness=20mm

Web Thickness=16mm

M.I.=1,0500 cm^4

Design of Secondary Girder

Load on main girder- w= P/L= 572.00 kN/m

Maximum cantilever moment, M = w*L2/8 =10296.000 kN-m

Maximum cantilever moment, M = w*L2/8 = 1029600000 N-cm

Moment of Inertia of each plate girder, I=  105000cm^4

Distance of extreme fibre C, D/2= 30 cm

Sectional Modulus of each girder, Z= I/C = 3500 cm^3

Yield strength of steel, fy= 300  N/mm^2

Yield strength of steel, fy, = 30000 N/cm^2

Required Total Sectional Modulus (M/fy) = 34320.000

Number of main plate girder required= (Total sectional modulus/sectional modulus of each girder)= 9.806

Providing 22 number hot rolled section as main girder,

Forming steel, FS=(22/9.806) 2.244

Measuring Settlement for static load test

We’ll measure the settlement of the pile upon the application of load by micrometers of accuracy up to 0.01 mm and stroke of 100 mm concerning a horizontal reference beam fixed on the ground. The measured settlement is the settlement of the butt of the pile.

Load Application in static load test procedure

The contractor will use a Single cylinder-acting hydraulic jack with a hydraulic power pack to apply load onto the pile head. Therefore they will place the jack on the top of the pile head to deliver an axial load to the test pile against the Kentledge. However, Fluid pressure developed in the hydraulic jack will be monitored by a calibrated pressure gauge and load calculated by multiplying the fluid pressure by the cross-sectional area of the ram of the jack. So, this is how the complete system can transfer the maximum load required for the test.

Measurement of Load

As I have said, the contractor will use a calibrated pressure gauge with a jack to measure the pressure and to calculate the corresponding load. And again the engineer from the contractor will supply the Certificates of calibration while calculating.

Measuring Movement of Pile Heads during static load test

Independent Reference frame

Indeed, We, the contractor, will set up an Independent reference frame to measure the movement of the pile. You’ll find the supports of the reference beams into the ground at a safe distance from the test pile so that the movement of the test pile doesn’t disturb it and the crib wall as well. 

Moreover, the dial gauges attached to the pile in diametrically opposite positions and equidistant from the pile axis will help us measure the pile movement. Furthermore, the dial gauges shall enable readings within an accuracy of 0.01 mm.

Protection of Testing Equipment

Obviously, the site people will protect all equipment for measuring load and movement from the weather and any external interference throughout the test period. However, The safety personnel will keep the construction equipment and persons not involved in the testing process at a safe distance from the test to avoid disturbance to the measurement apparatus.


In this case, the contractor should be responsible for carrying out all the works under the supervision of qualified, experienced, and trained engineers and technicians. So, they shall submit the list of personnel before the commencement of the test. Moreover, during the progress of a test, the engineer shall provide all the testing equipment and all test records as required during supervision.

Loading and Unloading Procedures Table

Fig: Loading and Unloading Procedures Table during bore pile static load test

Holding Time

A = Any time, if the rate of settlement is less than 0.25 mm /h

B = Max 2 h if the rate of settlement is greater than 0.25 mm/h

C = Any time after 12 h if the butt settlement is not greater than 0.25 mm in 1 h but otherwise 24 h

Reading Time:

D = At interval 10 min for 1st 2 h than, 1 h for next 10 h, 2 h for next 12 h.

When Pile Fails:

If pile fails at any load the pile will be jacked up to 15% of pile diagonal/dia of settlement.

Quality control and assurance

  1. Firstly, ensure the health and workability of all equipment and facilities employed for load Test.
  2. Secondly, an approved loading and unloading schedule should be maintained for the load test.
  3. Obviously each person on duty is responsible for his own work.
  4. Following this, Safety personnel are deployed to ensure safer work environments and intrusion of wild/unwanted animals to save the equipment from harm and to ensure a more accurate test.
  5. In addition, any kind of interference with the reference beam is prohibited to ensure accuracy of pile top displacement data.
  6. In cases of abnormal situations during the test, it is necessary to consult with the engineer and act
    according to suggestion.
  7. Proper steps are to be taken in cases of any natural hazard which might temper with the test.
  8. Proper guidelines will be followed to ensure accurate result.


Firstly, Entire testing area will be isolated by proper barrier so that entry of unwanted person and cattle’s can be stopped. Secondly, sufficient measures will be taken to secure the Kentledge against tilting and failure. Thirdly, during night work sufficient lighting will be arranged. Most importantly, all workers will use proper safety gears while present at work site.


We can learn important details about a structure’s strength, equilibrium, and general safety from the results of the static stress test. Engineers can identify any flaws or weaknesses in a structure that might impair its ability to endure practical loads or outside forces like earthquakes or windstorms by examining how the structure responds to a static load. Static load testing is a crucial instrument for guaranteeing the dependability and safety of machinery and structures across a range of sectors. It enables engineers to spot potential issues before they develop into significant problems and aids in ensuring that structures are constructed to the greatest standards of performance and safety.

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3 thoughts on “Static Load Test for bore piles: A complete guide!

  1. Very good effort to enrich the civil engineering topics. Worth to understand for the civil engineer. Thanks for your knowledge sharing way that can help a lots of civil team.

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