Accuracy of STATNAMIC pile load testing in the Citramall project Surabaya, Indonesia

Approximately 850 prestressed concrete piles having a cross-sectional area of 400 x 400 mm(2) and 24 m deep were driven to support the Citramall building with a design load of 1100 kN. In the early stage, 2 trial piles were driven and dynamically test loaded to establish the required design criteria for obtaining the load capacity of the pile. The accuracy of the project and the very tight schedule forced the project engineer to find an alternative, more accurate pile load testing method, giving direct confirmation of the applied load and the corresponding pile settlement during the test. Based on this requirement, the Statnamic load test was selected. Static pile load testing, however, was still applied on 2 selected piles adjacent to the piles tested with Statnamic to compare the load-settlement behaviour. In total, 4 Statnamic tests were conducted in this project. Results of the tests showed that the load-settlement diagrams of piles tested with Statnamic were in very close agreement: compared to those obtained using static load tests.