Standard Statnamic instrumentation consisting of a high quality load cell, photovoltaic displacement sensor (activated via laser projector) and a servo accelerometer has not changed over the years. However, this instrumentation has been augmented with additional accelerometers at the pile head. Also, the majority of all load test programs incledes strain gages and toe accelerometers cast within concrete piles or mounted on steel piles to provide subsurface foundation measurements. Thus, a more powerful data acquisition sysytem was required. Now, Redundant data systems are used for positive acquisition of the data. The original data acquisition termed FPDS developed by The Netherlands Organization (TNO) is shown at left and the powerful MEGADAC system is shown at right. The MEGADAC is capable of measuring almost every type of geotechnical or structural instrument either static, Statnamic or dynamic. It is capable of monitoring several hundred channels at virtually any sampling rate up to 5000 per second or more if required. It is not uncommon to record a hundred thousand data points during a half second load test. Such precision maps out foundation response subtleties with great resolution. All the data is readily available in ASCII format allowing efficient data regression. This device is probably the most versatile monitoring system on the market today.
TNO FPDS at left and MEGDAC system at right.
Statnamic load cells are made by two notable instrumentations companies, Geokon and George Kelk, Inc. These load cells are calibrated on a regular basis. Direct pile top displacement measurements are recorded by the photovoltaic sensor excited with a laser projector. Acceleration measurements are recorded top at several locations around the pile top. These highly accurate accelerometers also provide displacement measurements.