SMALL-SCALE SITE INVESTIGATIONS: FILLING A COSTLY GEOTECHNICAL VOID

The goal of this paper is to alert geotechnical professionals to the long neglected need for small-scale site investigations within urban areas and to offer examples of how geologists can provide consulting services to correct that oversight. Planners of major engineered structures routinely rely on geotechnical input to assure the desired longevity for the finished product, but most residential and small commercial buildings are completed without benefit of pre-construction site investigations. In the absence of site-specific data, foundation designs for small structures are largely determined by generalized and often inadequate building codes. In spite of published reports prepared by state and federal agencies that identify areas unsuited for conventional construction practices, developers and builders continue to follow the credo that “one approach fits all sites”. Experience of the author over the last 40 years in the St. Louis and Kansas City metropolitan areas indicates that, in most cases, the geotechnical conditions at small building sites are only scrutinized after differential movement, settlement, flooding, or slope instability has caused damage to the completed structure. Because of the paucity of geotechnical professionals available to make “house calls”, the homeowner is likely to have the “cause” of the damage diagnosed and a “cure” recommended by an unqualified foundation or landscape contractor. Clearly, our profession is not providing adequate service in such situations. At present, large geotechnical firms cannot economically mobilize staff and equipment to serve the needs of small-scale construction projects and most professionals employed by such firms are prevented from engaging in outside consulting activities. Accordingly, this paper is intended to provide examples of how an independent or retired engineering geologist can be of service to individuals who are building, buying or selling a residential structure and to describe the inexpensive equipment needs required to successfully enter the marketplace as a “residential consultant” in the urban arena.