In construction of drilled shafts under water, placing concrete in the shafts is
technically demanding and involves complex construction logistics. Past
construction experience has demonstrated that high quality concrete can be
placed in drilled shafts under water with a proper concrete mix and proper
placement techniques. However, a significant number of failures have occurred
which have resulted in excessive cost overruns and delays. These problems may
have occurred because proper underwater concrete construction techniques
have not been widely disseminated within the industry. This is a technical area
where competent design and sound construction planning can achieve a
significant reduction in both risk and cost. This paper will discuss some key
technical issues in the concrete mix design, concrete production and placement
for the drilled shaft construction. The paper also describes two lesson-learned
case histories from drilled shaft construction projects.
Author: Sam X. Yao & Robert B. Bittner, Ben C. Gerwick, Inc.
Publisher: DFI