5 Test methods

5.1 Tests on concrete

5.1 of EN 13369:2004 shall apply.

5.2 Measuring of dimensions and surface characteristics

Dimensions shall be verified in conformity with the methods given in Annex J of EN 13369:2004 and Annex E of this document. For the measurement of perpendicularity of the pile top and pile bottom against pile axis the measurement shall be made in two directions (e.g. horizontal and vertical directions).

5.3 Weight of the products

The weight of piles is calculated.

6 Evaluation of conformity

6.1 General

6.1 of EN 13369:2004 shall apply.

6.2 Initial type testing

6.2 of EN 13369:2004 shall apply.

Joint rigidity for segmental piles shall be tested following Annex A.

6.3 Factory production control

6.3, except 6.3.6.5, of EN 13369:2004 shall apply.

6.3.6.5 Finished products

Compliance verifications on the finished products shall be performed following Table 5. Other verifications can be performed when a special necessity arises.

The check shall be carried out at the earliest time possible, preferably in the factory or at the stack yard, and never after the precast units have been received and accepted by the client.

Table 5 — Finished product inspection
SUBJECT ASPECT METHOD FREQUENCY REGISTRATION
Elements Total length See 4.3 and 5.2 One every month for each casting line and any type of product Notation in the record form
Elements Straightness Visual inspection One visual for each casting line daily Notice of imperfections in the record form
See 4.3 and 5.2 One every month for each casting line Notice of imperfections in the record form
Elements Marking and Labelling Visual inspection Visual check daily Notation in the record form
Elements Other geometrical tolerances See 4.3 and 5.2 One every month for each casting line Notation in the record form

The manufacturer shall keep the records of the elements produced (unique code/mark, production location, date of casting, etc.) for the required period of archiving and shall provide these data when required.

7 Marking

The producer shall provide a manual in which, among other items, the meaning of the marking is described and instructions are given for the handling of the pile during transportation, storage and lifting on site.

Each foundation pile or segment shall be marked or labelled near the head of the pile. For segmental piles the pile joint type shall be indicated.

NOTE For CE marking see Annex ZA.

Markings, unambiguously indicating the points of support during storage and transportation, the hoisting points and, when necessary, the head and the toe of the pile element, shall be shown on the pile.

8 Technical documentation

The detailing of the element, with respect to geometrical data and complementary properties of materials and inserts, shall be given in technical documentation, which includes the construction data, such as the dimensions, the tolerances, the layout of reinforcement, the concrete cover, the expected transient and final support conditions and lifting conditions.

The composition of technical documentation is given in Clause 8 of EN 13369:2004.

Annex A

(normative)

Type test method for the verification of robustness and rigidity of pile joints

A.1 Impact load test with subsequent bending test

A.1.1 Principle

Impact load test with subsequent bending test consisting of submitting a segmental pile with cast in pile joint to a series of impact loads, which generates substantial stresses in the pile joint and in the pile segments. After impact test the gap between two joint halves is measured and the segmental pile is submitted to a two point load bending test, where the bending capacity of the pile joint is determined.

A.1.2 Apparatus

The following apparatus are used to perform the test:

  • pile driving rig with an impact hammer capable of achieving adequate stresses to the pile joint. The pile driving rig shall be capable of maintaining the submitted impact loads to an accuracy of ± 10 % of the specified value;
  • stress wave measurement device;
  • loading device for applying two equal vertical loads. The device shall be capable of increasing the load continuously and maintaining the chosen load level constant for the required time (3 minutes to 5 minutes). The force applied shall be measured to an accuracy of 3 %;
  • gauges for measuring deflections of the segmental pile due to imposed load during bending test to an accuracy of 0,1 mm;
  • gauge for measuring gap between two joints halves to an accuracy of 0,1 mm.

A.1.3 Test specimens

The test specimen is the segmental pile composed of two pile joint components.

When impact test is performed the length of the upper pile segment shall be at least 3 m. The bottom pile segment may be provided with a pile shoe and shall have a length, which ensures that the joint will remain above the ground during the impact test.

The three test specimens, one per test, are assumed to be identical.

A.1.4 Impact load test

The test piling shall take place in a well-defined area, where geotechnical investigation shows sufficient soil bearing capacity in a suitable depth. A reinforced foundation slab in the prescribed depth can also be used as a footing to increase the resistance during the driving operations.

The bottom pile segment is driven vertically until it stands firmly imbedded in the soil in such a way that the pile joint is above the ground and can be observed during the whole test. Care should be taken that failure in the pile does not occur, due to high stresses during driving.

After driving of the bottom segment the upper segmental pile is jointed to the lower segment.

The impact load test consists of impact blows to the segmental pile generating compressive/tensile stresses around the pile joint. The number of impact blows and the compressive stress level around the pile joint shall be according to pile joint class. The stress level in the pile is monitored by means of stress wave measurements.

After each 500 blows the joint and the pile section around the joint is visually examined, and findings are recorded. The penetration of the pile is also recorded. In addition to this, the alignment between the bottom — and top section of the pile is controlled to be not more than inclination 1:150.

A.1.5 Bending test

For the test, the segmental pile is cut to a length having slenderness (pile length/minimum dimension of the pile cross-section) between 11 and 12.

For the measurement of the gap v0 between two joint halves without external loading the segmental pile is supported as shown in Figure A.1. The gap v1 is measured when the segmental pile (loaded only by its own weight) is supported in the middle where the pile joint is located and gap v2 is measured when the segmental pile (loaded only by its own weight) is supported at both ends to an accuracy of 0,1 mm. The gap v0 is calculated from the equation: v0 = (v1 + v2)/2.

Measurement of the gap v0 between two joint halves without external loading
Figure A.1 — Measurement of the gap v0 between two joint halves without external loading

For the loading test the segmental pile is placed on two supports so that it is tested in its weakest direction with a span equal to 10 times the minimum dimension of the pile cross-section but at least 3 m. The pile joint shall be situated exactly in the middle of the span. In Figure A.2 the distance a is equal to L/3 + 2 times the minimum dimension of the pile cross section.

Bending test arrangement
Figure A.2 — Bending test arrangement

The test pile is loaded with two equal point loads in the third point of the span as shown in Figure A.2. Data to be recorded:

  • deflection is measured using three gauges, which are installed in point ai (at the middle of the span) and in points al and ar at a distance of (0,5 a) from the middle on the span (see also Figure A.2);
  • the first deflection measurement is made when the pile is exposed to its own weight only (zero reading). The increase of each load step is chosen in order that at least 10 load steps are made before ultimate bending moment has been reached. After each load step the load is kept constant for about 3 minutes before reading the gauges;
  • the gap, on the lower side of the test specimen, between the two joint halves, shall be measured and recorded during the test for each load step to an accuracy of 0,1 mm;
  • the failure load; the test is carried on to the point when failure in the test specimen occurs.

A.1.6 Evaluation of test results

The measured deflection values provide the background for calculating the flexural stiffness from the following formula:

where see Figure A.2

a = L/3 + 2h, in which h is the depth of the pile, see also Figure A.2;

M = bending moment in the pile joint caused by imposed load;

δm = deflection in the middle of the span = δi – (δl + δr)/2 where δi, δl and δr are respectively the displacements of points ai, al and ar.

If all 3 test specimens perform satisfactorily during the impact test, e.g. no failure occurs in the pile joint during the driving test and failure in the pile joint during the bending test occurs after the calculated bending moment in the pile joint has been reached, then the test shall be deemed satisfactory.

A.1.7 Test report

The test report shall include the following information:

  • number, title and date of issue of this document;
  • name of this Annex A and title of test method (impact load test with subsequent bending test);
  • identification of the tested pile joints in relation to production drawing;
  • material certificate of the components of tested pile joints including measured material strengths;
  • identification of the pile segments in relation to production drawing;
  • dates and place of manufacture of tested pile joints and pile segments;
  • place and date of testing, testing institute and name of the person responsible for testing;
  • intended pile joint class;
  • number of impact blows using different stress levels around the pile joint and the stress levels achieved;
  • results of the stress wave measurements in impact test;
  • observations, penetration of the pile and inclination of pile top and bottom segments after each 500 blows in impact test;
  • gap v0 between two joint halves without external loading;
  • observations of the test specimens (e.g. cracks or deflection) before bending test;
  • bending test arrangement i.e. span;
  • load chart and load deflection diagram in bending test (deflections as absolute values);
  • gap in the joint for each load step in bending test;
  • calculated bending moment in the pile joint taking into account the actual strength of the materials, short term loading and γm = 1;
  • calculated bending moment, in the lowest value for the shaft and the joint, taking into account the design strength of the materials;
  • load and bending moment at yielding and at failure;
  • flexural stiffness of the pile joint at the level of 0,75 x calculated characteristic bending moment of the pile joint;
  • observations of the test specimens after termination of test.

EN 12794:2005 Precast concrete products – Foundation piles