Abstract
Construction and design of drilled shaft foundations in hard limestone requires flexibility from all parties involved due to the variability of the subsurface conditions. Strategies that have been found useful in the birmingham, alabama, area are described. The importance of well-trained and experienced field personnel in these conditions is noted. It is also vital that engineers understand the construction challenges so as to provide both quality assurance and cost-effectiveness in design and in the specifications. This paper appearsin transportation research record no. 1277, Modern geotechnical methods: instrumentation and vibratory hammers 1990.