2.8 Geotechnical Design Report

(1)P The assumptions, data, methods of calculation and results of the verification of safety and serviceability shall be recorded in the Geotechnical Design Report.

(2) The level of detail of the Geotechnical Design Reports will vary greatly, depending on the type of design. For simple designs, a single sheet may be sufficient.

(3) The Geotechnical Design Report should normally include the following items, with cross- reference to the Ground Investigation Report (see 3.4) and to other documents, which contain more detail:

  • a description of the site and surroundings;
  • a description of the ground conditions;
  • a description of the proposed construction, including actions;
  • design values of soil and rock properties, including justification, as appropriate;
  • statements on the codes and standards applied;
  • statements on the suitability of the site with respect to the proposed construction and the level of acceptable risks;
  • geotechnical design calculations and drawings;
  • foundation design recommendations;
  • a note of items to be checked during construction or requiring maintenance or monitoring.

(4)P The Geotechnical Design Report shall include a plan of supervision and monitoring, as appropriate. Items, which require checking during construction or, which require maintenance after construction shall be clearly identified. When the required checks have been carried out during construction, they shall be recorded in an addendum to the Report.

(5) In relation to supervision and monitoring the Geotechnical Design Report should state:

  • the purpose of each set of observations or measurements;
  • the parts of the structure, which are to be monitored and the locations at which observations are to be made;
  • the frequency with which readings are to be taken;
  • the ways in which the results are to be evaluated;
  • the range of values within which the results are to be expected;
  • the period of time for which monitoring is to continue after construction is complete;
  • the parties responsible for making measurements and observations, for interpreting the results obtained and for maintaining the instruments.

(6)P An extract from the Geotechnical Design Report, containing the supervision, monitoring and maintenance requirements for the completed structure, shall be provided to the owner/client.