1 of 18  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 06: Concrete and Steel Works  A structural member shall not deviate from its intended length by more than:   1 mm in the case of compression members faced at both ends for bearing, or   + 0 to - 4 mm in the case of other members.  Lengths of components shall be such that cumulative variations do not prejudice the accurate align- ment of the completed structure.  Where two steel surfaces are required to be in contact to effect a bearing or frictional contact, the sur- faces shall be prepared so that at least 90% of the area is touching before any clamping force is ap- plied.  6.4.13 Dissimilar metals  Where dissimilar metals are used in close proximity to structural steel members or their connections,  contact between such metals and the steel shall be avoided unless the Contractor can demonstrate to  the satisfaction of the Engineer that contact between the dissimilar metals will not lead to galvanic cor- rosion.  Contact between aluminum or aluminum alloy and galvanized mild steel shall be permitted. For fixing  aluminum to steel structures, bolts, nuts, washers and screws shall be galvanized.  Where galvanized parts may become sacrificial anodes to the main structure or where the electrolytic  potential difference exceeds 250 mV, the parts shall be separated by an insulating medium of adequate  strength.  The requirements for stainless steel are given in Section 7.3.4 of these Specifications.  6.4.14 Stainless steel  6.5 Structural Design Requirements  6.5.1 General  The Contractor shall carry out and document the structural design for the structures and buildings,  which are defined to be under the responsibility of the Contractor as minimum in accordance with the  requirement given in this section below. The structural design requirements should be implemented for  the structural design that expressed above.  Structures should be capable of withstanding external lateral soil pressure when empty.  Structures should be capable of withstanding internal pressure when filled with water and assuming no  lateral external load from soil and/or groundwater.  Combined structures should be capable of withstanding internal water pressure when one compartment  is filled with water and the adjacent compartment is empty.  Structures should be capable of withstanding both external pressure support from soil and/or ground- water and internal pressure when filled with water. The pressure from ground water and any external water should be taken into consideration.  All structures should be secured against uplift by their own weight together with the surrounding soil.  6_Vol3_d4.3_Section 6 Concrete and steel works_en_GIR_rev6.docx 