Depth evaluation testing
When a further load needs to be added onto an existing pile, for instance in a building addition planned according to the Israeli Planning Guidelines for Seismic Strengthening (TAMA 38), the depth of the existing piles needs to be ascertained. This test is required so that the planner and the basing consultant can take the existing situation into account and plan the necessary reinforcement to the building addition. The depth evaluation test is carried out in the sonic method, allowing us to ascertain the depth of an existing pile (whose actual depth is actually unknown). As opposed to a regular sonic test, where the depth of the actual pile is known, in a depth evaluation test old piles (aged 25-30 years) are usually tested, and the original building plans are absent.
The test is carried out on the exposed side of a pile carrying any other constructed body, such as beam, wall or column. The exposed pile must be thoroughly cleaned, allowing adequate access to the test site. This kind of test usually lacks certain data, such as the concrete’s age, the method in which it was poured, its kind and its strength. The tested pile in this case is attached to beams, walls and columns, which sometimes affect the way a test wave is returned.
A depth evaluation test requires much experience and expertise in the process of testing and interpreting, taking into consideration the test’s location, comparison to adjacent piles and data on the soil’s profile. Any deviation or defect requiring a depth evaluation test might look like the end of the pile, and testing its lower regions is impossible.