Dynamic Pile Load Test of Cast-in-Place Concrete Piles-German Practice and Codes

摘要

For over 30 years, cast-in-place concrete piles have been dynamically load tested in Germany. In the first 10 years (up to about 1995) this test method was only applied for special cases, and the involved parties were well aware of the differences between dynamic and static load tests. Since then, this method was more and more frequently executed as a low-cost static test, often merely to support the business of piling contractors-i.e., selling piles. Many tests were carried out with low-impact energy because the available drop weights had only up to 12 tons. Thus, the geotechnical and engineering aspects of the test method were more and more neglected. Some clients accepted what was delivered despite the fact that EC 7 defines a clear safety concept for dynamic pile load tests. Given this situation, one main public authority wanted to examine the proficiency of the German pile testers and prepared a series of controlled tests. As a consequence, recommendations of the German Geotechnical Society were revised, and an addendum was published. It is the intent of this paper to show that dynamic pile load tests are a reliable and valuable tool for axial bearing-capacity assessment for cast-in-place piles and will provide useful results if the tests are conducted by experienced engineers in accordance with the revised recommendations. cast-in-place piles; dynamic pile load tests; signal matching; German practice; recommendations; pile testing