4.2.4.

(1) The design of foundations, excavations and soil – and rock-retaining structures shall be based on a subsurface investigation carried out by a person competent in this field of work, and on any of the following:

(a) application of generally accepted geotechnical and civil engineering principles by a person especially qualified in this field of work as provided in this Section and other Sections of this Part,

(b) established local practice where such practice includes successful experience both with soils and rocks of similar type and condition and with a foundation or excavation of similar type, construction method, size and depth, or

(c) in situ testing of foundation units such as the load testing of piles, anchors or footings carried out by a person competent in this field of work.

(2) The foundations of a building shall be capable of resisting all the loads stipulated in Section 4.1., in accordance with limit states design in Subsection 4.1.3.

(3) For the purpose of the application of the load combinations given in Table 4.1.3.2.v1, the geotechnical components of loads and the factored geotechnical resistances at ULS shall be determined by a suitably qualified and experienced person.

(4) Geotechnical components of service loads and geotechnical reactions for SLS shall be determined by a suitably qualified and person.

(5) The foundation of a building shall be designed to satisfy SLS requirements within the limits that the building is designed to accommodate, including total settlement and differential settlement, heave, lateral movement, tilt or rotation.

(6) Communication, interaction and coordination between the designer and the person responsible for the geotechnical aspects of the project shall take place to a degree commensurate with the complexity and requirements of the project.

(1) A subsurface investigation shall be carried out to the depth and extent to which the building or excavation will significantly change the stress in the soil or rock, or to such a depth and extent as to provide all the necessary information for the design and construction of the excavation or the foundations.

(1) The identification and classification of soil, rock and groundwater and descriptions of their engineering and physical properties shall be in accordance with a widely accepted system.

(1) Except as permitted in Sentence (2), the bearing surface of a foundation shall be below the level of potential damage, including damage resulting from frost action, and the foundation shall be designed to prevent damage resulting from adfreezing and frost jacking.

(2) The bearing surface of a foundation need not be below the level of potential damage from frost where the foundation,

(a) is designed against frost action, or

(b) overlies material not susceptible to frost action.

(1) Where a foundation is to rest on, in or near sloping ground, this particular condition shall be provided for in the design.

(1) Where there is eccentricity or inclination of loading in foundation units, this effect shall be fully investigated and provided for in the design.

(1) Where dynamic loading conditions apply, the effects shall be assessed by a special investigation of these conditions and provided for in the design.

(1) Where a foundation or any part of a building is subject to hydrostatic uplift the effects shall be provided for in the design.

(1) Where proposed construction will result in a temporary or permanent change in the groundwater level, the effects of this change on adjacent buildings shall be fully investigated and provided for in the design.

(1) Where conditions of permafrost are encountered or proven to exist, the design of the foundation shall be based upon analysis of these conditions by a person especially qualified in that field of work.

(1) Where swelling or shrinking soils, in which movements resulting from moisture content changes may be sufficient to cause damage to a structure, are encountered or known to exist, such a condition shall be fully investigated and provided for in the design.

(1) Where rock that expands or deteriorates when subjected to unfavourable environmental conditions or to stress release is known to exist, this condition shall be fully investigated and provided for in the design.

(1) Buildings may be placed on fill if it can be shown by subsurface investigation that,

(a) the fill is or can be made capable of safely supporting the building,

(b) detrimental movement of the building or services leading to the building will not occur, and

(c) explosive gases can be controlled or do not exist.

(1) The structural design of the foundation of a building, the procedures and construction practices shall conform with the appropriate Sections of this Code unless otherwise specified in this Section.