Page 18 - Building Regulation and Design Guidelines - Structural (Grey Code)
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SECTION: 1  GEOTECHNICAL GUIDELINES & REGULATIONS                                     SECTION: 1  GEOTECHNICAL GUIDELINES & REGULATIONS




                     1.3.6   SHALLOW FOUNDATIONS
                          -   The foundation level should be in compliance with the architectural
                              requirements.                                                                                1 PILE  2 PILE  3 PILE  4 PILE  5 PILE  6 PILE
                          -   Net allowable bearing pressure to be determined considering
                              shallow foundations at the foundation level using practical
                              experience and the results obtained from the field standard                                    7 PILE  8 PILE  9 PILE  10 PILE
                              penetrations tests, the empirical equations developed by Terzhagi
                          -   Peck/Merehof and modified by Bowles considering a proper FOS
                              against shear failure of the soil.
                                                                                                                              11 PILE   12 PILE  13 PILE
                          -   Using the calculated allowable bearing pressure value, the total
                              settlement for isolated/strip footing and raft foundation shall be
                              within 25mm & 50mm respectively. The differential settlements
                              should be indicated.
                                                                                                                              14 PILE   15 PILE  16 PILE
                          -   The proposed foundation recommendations must ensure that an
                              adequate safety factor against likely uplift pressure established                                 Fig. (1.15): Piles Distribution
                              based on selected Design GW level is satisfactory to local authority
                              and / or project requirements particularly when basement floor(s)                 -   The geotechnical report shall include an estimate of single pile vertical
                              exist.                                                                                and lateral stiffness for the adopted pile cut off levels and penetration
                                                                                                                    depths. Lateral stiffness shall be based on cyclic conditions. The
                          -   Modulus of sub-grade reaction ks (kN/m3) shall be indicated in the                    assessment of pile group effects on vertical and lateral stiffness shall
                              soil report when the raft foundation is recommended.                                  be performed by the foundation design Engineer.
                          -   The foundation ground must be proof rolled with vibratory                         -   For bored cast-in-situ piles, settlements of the order of 1% of the pile
                              compactor to confirm that any loose materials are compacted to not                    diameter is normally required to mobilize full skin friction whereas
                              less than 95% of the maximum dry density obtained by performing                       full bearing is developed at much higher settlements (usually at 10%
                              modified Procktor test.                                                               of pile diameter). Therefore, it is recommended that the pile capacity
                                                                                                                    shall be based on full skin friction and partial end bearing.
                          -   The specialist should confirm in writing that the undesirable
                              materials have been removed, the foundation ground has been                       -   Where the borehole depth is not satisfactory for the design,
                              inspected and the recommended bearing capacity corresponding to                       additional boreholes should be carried out to the required depth to
                              the foundation depth is properly achieved.                                            reconfirm the continuity of the strata. Fig. (1.15): Piles Distribution


                     1.3.7   PILE FOUNDATIONS                                                              1.3.8   FOUNDATION CONCRETE
                          -   The  soil  report  should  propose  the  suitable  type  of  pile  to  be         Concrete mix design should consider strictly the chemical analysis data
                              used, the allowable working loads in compression and tension                      for both soil and water and to be in line with Trakhees Construction
                              considering minimum factor of safety of 2.5. Piles spacing should                 Materials Quality Control Guidelines.
                              be recommended in the piling recommendations Minimum 2.5 the
                              pile diameter, Fig. (1.15). It should be noted that the minimum pile         1.3.9   LIQUIFACTION:
                              toe level should be at least at depth of two times the diameter of
                              pile socketed in the hard strata in order to consider this strata in              The likely liquefaction induced effects are:
                              the design.                                                                       -   Settlement.

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