Geotechnical Engineering - Experience is Paramount
Some people within the design and construction community think geotechnical engineering and foundation recommendations are all about the experience of the Geotechnical Engineer-of-Record. On the other hand, many believe that geotechnical engineering is mostly about satisfying requirements of the general building code, which primarily comprises the International Building Code (IBC), germane portions of the American Society of Civil Engineers (ASCE/SEI 7), and specific statewide codes. Neither of these thought processes is correct when isolated individually, but both thought processes are critical to the process.
Local knowledge and experience are essential when developing a geotechnical report and foundation recommendations, as they allow the engineer to accurately assess site-specific soil conditions, geological features, and potential risks that may not be readily apparent to someone unfamiliar with the area. This results in more reliable and informed design recommendations for construction projects. Still, the project geotechnical engineer must comply with all of the code-required acceptance criteria specified in Chapters 17 and 18 of the IBC code and relevant provisions set forth by the ASCE/SEI 7 standard.
IBC Section 1705.6 requires special inspections and tests of existing site soil conditions and stipulates that fill placement and load-bearing requirements shall be performed in accordance with Section 1705.6. The approved geotechnical report and the construction documents the registered design professionals prepared shall be used to determine compliance. The load-bearing capacity of the supporting soil has a significant impact on the structural integrity of any building. Proper compaction, lift, and density are crucial to achieving the design bearing capacity as set forth in the approved geotechnical report. IBC Chapter 18, Section 1803, specifies extensive code-required criteria that must be included in the geotechnical report. Finally, IBC Chapter 18, Section 1804.6, requires that the fill material must comply with the provisions of the approved geotechnical report as set forth in Section 1803.
IBC Section 1803.1 (Commentary) The field of soils mechanics and foundation engineering is diverse and complicated, and since it is not an exact science, its application requires specialized knowledge and judgment based on experience. Where subsurface conditions are found or suspected to be of a critical nature, the building official is encouraged to seek the professional advice of experienced foundation engineers.
For more information or further enthusiastic discourse on topics of CODE, please contact Alan Tuck at: [email protected] or 540.344.7939.