320.5 Foundation Investigations
This guidance defines responsibilities and establishes procedures for conducting special investigations of critical foundation areas.
It is the responsibility of the District to locate possible critical foundation areas during the soil survey and submit a request for an investigation to the State Construction and Materials Engineer. Excepting those District responsibilities outlined in Drilling Operations, the investigation is then the responsibility of the Construction and Materials Division. Special foundation investigations may also be initiated by Construction and Materials Division should a need become evident during final soundings for structures or other work supervised by Construction and Materials Division personnel. Investigations may be initiated at either the Division or District level for those foundation problems not detected until construction of the project.
A letter should be submitted by the District requesting the Construction and Materials Division to perform an investigation. In emergency situations, requests may be initiated by phone, followed by written confirmation. These requests should include the latest date the information is needed. Except in emergency situations, the normal minimum time desired for completion of an investigation is about six months. As long as a year could be required depending upon work loads, priorities, ground conditions, and the severity of the problem. Pertinent information such as logs of preliminary borings, difficulty of access due to crops or soft ground, etc., should also be included in the letter of request. Upon receipt of the request, the necessary personnel and equipment will be assigned. The investigation may include, as applicable, subsurface exploration, special field or Laboratory testing, analysis of data, development of recommendations, and reporting.
The investigation will be reported in letter form. Distribution of reports is individually considered. Normally, the District requesting the investigation will receive the original and copies will be sent to any concerned Divisions. When the request originates from a Division, copies may be attached to the original for later distribution at the discretion of the requesting Division.