34 of 49 Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 05: Earth Works, Pipe Works and Ground Improvement  Wick drains shall be composed of two parts: inner core and filter material. These may be manufac- tured as a single material or the filter may be wrapped around the core, and overlapped to keep the  core closed inside.  Wick drains shall be, 100 mm wide, 6 mm thick polyester (PES) or polypropylene (PP), or similar,  with the approval of the Engineer.  Wick drains shall be flexible, capable of being rolled to a 300mm diameter drum without damage. The  wick drain must be strong enough so it will not break, tear or loose its drainage properties during in- stallation. The core of the drain shall resist crushing or formation of kinks when bent.  The positions of the wick drains shall be at most 100 mm away from the coordinates shown on the  drain layout drawings.  Vertical deviation of the drains shall be at most 1Horizontal in 50Vertical. Wick drains shall be cut at least at least 150 mm above the working platform.  Daily reports shall be written for the drains installed. A copy of these reports shall be presented to the  Engineer within two days after installation. The records shall include:   date   reference area and grid for each drain   depth of installation for each drain   obstacles and delays   readings of the installed instruments.  Any unexpected conditions experienced and reported will be briefly mentioned in these records. After all field works are completed, five copies of the Final Report will be presented to the Engineer  within two (2) weeks after removing the preloading fill.  Method of preloading with wick drains shall be approved by the Engineer.  5.4.6 Pile Foundations  5.4.6.1 General  Pile foundation may be necessary for supporting structures where the subsoil is considered to have  insufficient bearing capacity. The Contractor shall carry out detailed design of these structures in ac- cordance with the Contract Conditions and Employer’s Requirements and shall determine the type of  foundation required, the number of piles and their working loads and the optimum arrangement of  piles required for supporting the structures.  Excavation, concrete steel reinforcement and steel casing where applicable shall conform to the rele- vant sections of the herewith Volume 3 Employer’s Requirements.  At least 21 days before the Contractor intends to commence piling work on the site, the Contractor  shall submit for the Engineer’s approval full details of his proposed piling system including the type  and dimensions of piles, reinforcement details and full details and full design and driving calculations.  The details to be submitted shall include the Contractor’s proposals for equipment, temporary works  and construction methods.  No work on piling shall commence on the site until the Engineer’s approval to the Contractor’s pro- posal has been received.  5_Vol3_d4.3_Section 5 Earth and pipe works_en_GIR_rev6.docx 