Instrumented Pile Load Tests
A conventional static load test on a pile provides limited information as we monitor load and displacement only at pile top. However, if the load test is complemented with instrumentation it provides much more information. Geo Dynamics provides instrumentation for vertical load tests by placing vibrating wire strain gages at pre-selected levels on reinforcement cage. A conventional static load test conducted provides readings from strain gages at each location and it is then possible to evaluate unit friction from a set of complex calculations and expert interpretation. Extensometers are also installed at specified levels for measuring pile shaft movements. For lateral load tests and to monitor lateral ground movement, Geo Dyanmics provides inclinometer services to plot the lateral movement of the ground or pile and also to determine the depth of fixity.
Geo Dynamics has successfully conducted instrumented load tests for Cochin Metro for a large 2m pile and for several other clients. Our work has been verified by international experts. We have been able to break the myth in India that instrumentation works only on paper. Currently, Geo Dynamics is well-equipped to provide instrumentation for bored piles for vertical and lateral load tests to accurately evaluate friction, end bearing, unit skin friction, elastic compression, lateral deflection etc.
It is imperative that an instrumented load test is planned properly and well in advance with a proper choice of number and location of vibrating wire strain gauges. Interpretation of the tests require several calculations and need an expert with good understanding of pile soil interaction.
There are no specific guidelines for fixing the amount and type of strain gages or extensometers. Thus it is imperative that there is agreement with the client to ensure adequate numbers to avoid redundancy of gages. The actual test is conducted as per IS:2911 (Part:4)