<p><p><strong>Reference(s):</strong></p><p><em>Coastal Caisson Corp. (2009)<br>DGGT AK2.8 (2002)<br>Dumas et al. (2003)<br>Scheller and Reitmeier (2000)</em></p><p><strong>Method Summary</strong></p><p>Before beginning production, it is necessary to install calibration and test columns to verify structural design and determine installation parameters for the production columns. This also gives the contractor a chance to demonstrate installation methods and equipment needed to meet the project requirements. Requirements for drilling, withdrawal, and rotational speed, as well as crowd pressure and the minimum amount of material required per column, should all be determined during calibration column installation. After installation parameters have been determined, test columns should be installed and evaluated in a two-fold manner. Some should be excavated from the ground to verify continuity through visual observation and to perform compressive strength testing on samples. Others should be left in place and load tested to evaluate capacity and settlement. Trial columns may not be used as production columns. Trial columns should be installed at numerous representative locations on the site. In the event that there is an unexpected change in soil parameters or stratigraphy during installation of production columns, additional trial columns may be needed to verify the installation parameters and procedure in such areas.</p><p><strong>Accuracy and Precision</strong></p><p>If production columns are installed using the same installation procedure, speeds, and pressures, trial columns provide an accurate and precise method for evaluating column design and installation parameters.</p><p><strong>Adequacy of Coverage</strong></p><p>Excavation of columns allows for compressive testing and continuity verification along the length of the column. The amount of trial columns is usually very limited, but can be placed at representative locations at the site.</p><p><strong>Implementation Requirements </strong></p><p>The same equipment is used for installation of production columns.</p><p><strong>General Comments</strong></p><p>Trial columns to determine installation parameters and design are necessary for all CSV applications.</p></p>