<p><p><strong>References:<br></strong><em>Bruce and Juran (1997)<br>Gibler et al. (2005)<br>Gomez et al. (2008a, 2008b)<br>Sabatini et al. (2005)</em></p><p><strong>Method Summary</strong></p><p>Ultimate tests are conducted before production pile installation in order to obtain information about the performance of micropiles at the project site given methods of construction, materials, etc. This information is then incorporated into the final design. For this reason, ultimate tests are technically not a QC/QA method. For projects that utilize ultimate tests, the relationship of ultimate tests to other static load tests, verification and proof tests, and the contribution of ultimate tests to selected installation methods should be understood. Ultimate tests are similar to verification tests, with the exception that ultimate tests are intended to be run to geotechnical failure. Failure is defined as the inability to maintain a constant load without excessive micropile movement or sudden loss of ability to support the load. The micropiles are individually tested using a static load which is applied in compression, tension, or laterally and movement of the micropile head is measured for each load increment. The micropile is loaded and unloaded in increments until the micropile demonstrates failure. Ultimate tests on micropiles allow the Contractor to demonstrate and optimize his specific means and methods. Typical load testing equipment includes: a hydraulic jack and pump; reaction and reference beams; pressure gauges and load cells; dial gauges; and a wire with mirror and scale (Sabatini et al., 2005). A creep test is performed as part of the ultimate test.</p><p><strong> </strong><strong>Accuracy and Precision</strong></p><p>Ultimate testing accurately and precisely assesses the ultimate strength of the micropile given the specified design and construction processes.</p><p><strong>Adequacy of Coverage</strong></p><p>Depending on the site and project conditions, ultimate tests may not be required.</p><p><strong>Implementation Requirements </strong></p><p>The requirements of ultimate testing are significant. The amount of time required to perform ultimate tests are greater than proof or verification testing. As a result, performing ultimate tests are more expensive than proof or verification tests.</p><p><strong> </strong><strong>General Comments</strong></p><p>Ultimate tests, also referred to as pre-production tests, offer a detailed range of information about the performance of the micropile system in the project environment. The results of an ultimate test can be used to provide an opportunity to verify the strength capacity of the micropile, establish load-deformation behavior, identify causes of pile movement, workmanship, method of construction, suitable interaction of materials, and verify the appropriateness of the assumed rock/soil shear strength to be used in design of production micropiles. The average ultimate bond strength and the ultimate pile capacity can be calculated based on the results of an ultimate test. The ultimate bond strength values can be used to confirm the ability of the micropile to support an expected service load. When conducting an ultimate test it must be verified in advance that the geotechnical capacity of the pile will be exceeded before the structural capacity of the pile exceeds 80% ultimate. Ultimate tests are not required for all projects and are typical for only large projects for which a design phase test program can be justified.</p></p>