4 Information needed

4.1 Any information relevant to the execution of the works on site shall be provided with the specification for the works.

4.2 The following minimum information should be considered and made available before commencement on site:

a) ground investigation report(s) at the construction site, as well as additional information of the subsoil at the building site, such as the presence of:

  • structure and foundation remnants;
  • artificial elements (utility lines and services);
  • underground contamination or hazards;
  • presence of fill material;
  • obstructions;

b) specifications on design and execution of the piling works and additional requirements for the supervision, monitoring or testing of the works;

c) present topographic data, such as:

  • slope, actual ground level;
  • location of main grid lines and site datum level;
  • piling platform level(s) related to site datum;

d) site conditions and limitations which can affect the piling work, such as:

  • size of working area, topography, slope, access roads, access limitations for equipment and materials, head-room restrictions;
  • concurrent activities, e.g. dewatering, tunnelling, deep excavations;
  • presence of trees, overhead cables / power lines;
  • proximity of potential unstable slopes;

e) environmental conditions and limitations which can affect the piling work, in relation with:

  • presence and condition of sensitive buildings or installations in the vicinity of the piling works;
  • environmental restrictions e.g. on noise, vibration or pollution;
  • any legal or statutory restrictions e.g. time restrictions;

f) other aspects such as:

  • possible corrosion and abrasion problems;
  • previous experience with displacement piles or other foundation methods on or adjacent to the site;
  • foundations of adjacent buildings.

4.3 Any additional or deviating requirements falling within the permission clauses given in this standard shall be established and agreed before the commencement of the works and the quality control system shall be suitably amended, e.g. for:

  • reduced or increased geometrical construction deviations;
  • application of different alternative construction materials;
  • special reinforcement, e.g. the use of steel tube or steel sections or fibres (steel or manmade);
  • grouting of pile shafts or bases;
  • use of rock shoes;
  • use of driving assistance (preboring, waterjetting,...);
  • use of friction reducing coatings.

5 Site investigation

5.1 The general requirements for the ground investigation are contained in ENV 1997-1:1994.

5.2 The ground investigation shall be sufficiently extended to recognise the presence of all ground formations and layers affecting the construction and performance of the piles, and to determine their characteristic strength and deformation properties required for the design.

5.3 The following information, when relevant for the execution of displacement piles should be given in the ground investigation report(s):

  • a) ground level at any point of investigation or testing relative to the recognised national datum or an agreed reference point;
  • b) presence and characteristics of loose or soft soils or ground that is likely to soften, loosen or become unstable during the execution of displacement piles;
  • c) presence of cobbles and boulders or other natural or artificial underground obstructions that can cause difficulties for the installation or could require special methods or tools for their penetration or removal;
  • d) the thickness, level and characteristics of soft strata below the bearing stratum that could affect the pile foundation performance;
  • e) presence, extent and thickness of any strata that can be sensitive to water infiltration or to stresses caused by piling tools (e.g. impact or vibration);
  • f) piezometric levels of groundwater and its variation, including any artesian groundwater tables and water wells;
  • g) any strata where high ground water velocities exist;
  • h) aggressiveness of groundwater or ground that could affect the durability and setting of the pile material;
  • i) level and inclination of any relevant underlying rock / surface;
  • j) thickness and extent of any existing weathered rock;
  • k) presence, extent and thickness of contaminated soil or waste, that can influence the pile quality and the handling and disposal of any excavated material or lead to contamination of underlying strata.

6 Materials and products

6.1 General

6.1.1 All material and products for incorporation into the displacement pile shall be in accordance with the relevant European Standard(s), technical requirements and/or with the specification for the works.

6.1.2 The sources of supply of materials:

  • shall be documented; and
  • shall not be changed without prior notification.

6.1.3 The dimensional tolerances shall comply with relevant European Standards.

6.1.4 Where a pile shoe is used it shall comply with the relevant material standard or specification.

6.2 Prefabricated displacement piles

6.2.1 Concrete piles

6.2.1.1 The materials and fabrication of prefabricated concrete piles, including joints, shall comply prEN 12794:1997.

6.2.2 Steel Piles

6.2.2.1 The materials, and fabrication of steel piles shall as a minimum comply with ENV 1993-5.

6.2.2.2 Re-used and second choice steel piles shall as a minimum comply with the requirements concerning type, size, tolerances, quality and steel grade specified in the design and be free from damage and corrosion that would affect strength and durability.

6.2.2.3 Concrete which is subsequently cast in a steel pile shall comply with ENV 206.

6.2.3 Timber piles

6.2.3.1 The materials, fabrication and handling of timber piles shall comply with ENV 1995-1-1 unless specified otherwise in the following paragraphs.

6.2.3.2 Hewn piles shall be evenly tapered. The section dimensions should not change more than 0,015 m/m. The straightness of the pile shall not deviate from the straight line more than 1 % of the length.

6.2.3.3 Piles shall be provided in one piece unless otherwise approved.

6.2.3.4 Preservation methods shall comply with the specification.

6.2.4 Cast Iron piles

6.2.4.1 Cast iron piles shall comply with the specification of the manufacturer and the design.

6.3 Cast in place displacement piles

6.3.1 All material and products incorporated into the pile shall be in accordance with EN 1536 unless specified otherwise.

6.3.2 Semi dry concrete may be used if tamped during installation. The cement content for semi dry concrete shall be of at least 350 kg/m3. The strength class shall be at least C25/30 and workability as specified.

6.4 Grout

6.4.1 Grout shall comply with EN 1536.

6.5 Paints, coatings and other shaft protections

6.5.1 Coatings used to reduce shaft friction shall comply with the specification.

6.5.2 Paints, coatings and other means of corrosion protection, or preservation products for piles, shall comply with the specifications in the design and be applied in accordance with the manufacturers instruction.

EN 12699:2001 Execution of special geotechnical work – Displacement piles