SITE INVESTIGATION
                               Assist. Prof. Berrak TEYMUR
                           Foundation Engineering
                        • Analysis       Design       Construction
                        • As a foundation engineer, you need to 
                          consider 
                           – geotechnical/structural issues (involves geology, 
                             subsurface exploration, structure type and load 
                             type), 
                           – professional engineering issues (cost-
                             constructability-reliability) 
                           – engineering modelling (how accurate and how 
                             reliable?).
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                                                  Steps in Foundation 
                                                           Engineering
                                         –Understand project and site
                                         –Develop design criteria
                                         –Identify possible foundation alternatives
                                         –Conduct soil investigation
                                         –Characterise site
                                         –Engineering analysis to evaluate alternatives
                                         –Develop recommendations and write reports
                                         –Monitor design, construction and performance
                                        Potential Problems Related to 
                                                    Foundation Design
                                     •  Bearing capacity failure of foundation (strength of 
                                        soil)
                                     •  Differential settlement of foundation
                                     •  Excessive overall settlement of foundation
                                     •  Instability of foundation, embankment, slopes
                                     •  Sulphate attack on concrete (groundwater)
                                     •  Damage to surrounding structures due to excavation 
                                        and dewatering an excavation
                                     •  Collapse of excavation as a result of excessive water 
                                        in flow.
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                                     Site Investigation
                               A soil investigation program is necessary to 
                               provide information for design and 
                               construction and for environmental 
                               assessment.  
                           Purposes:
                           1.  To evaluate the general suitability of the site 
                               for the proposed project
                           2.  To enable an adequate and economical 
                               design to be made
                           3.  To disclose and make provision for difficulties 
                               that may arise during construction
                                Site Investigation Phases
                            • Phase-I:  Collection of preliminary 
                              information
                               –obtain information regarding the type of 
                                 structure to be built and its general use. 
                               –A general idea of the topography and the 
                                 type of soil
                               –Geological survey maps etc.
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                   Site Investigation Phases
                 • Phase-II: Reconnaissance
                  –The engineer should always make a visual 
                    inspection of the site. 
                  –to provide a general picture of the 
                    topography and geology of the site. 
                   Site Investigation Phases
               • Phase-III: Site Investigation
                 –consists of planning, making test boreholes 
                  and collecting soil samples
                 –For a 30.5m wide building, depending on 
                  number of stories (1 to 5 stories) 3.5m to 24 
                  m deep borings can be made. 
                 –For a multi story building borehole spacing is 
                  10-30m.
                 –The exploration cost is generally 0.1-0.5% of 
                  the cost of the structure. 
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