Case Study: Application of the Observational Method Using High Strain Dynamic Tests

In-situ High Strain Dynamic Testing (HSDT) was developed more than 40 years ago. When a hammer or drop weight strikes the top of a pile, a compressive stress wave travels down its shaft at a speed that is a function of the elastic modulus and mass density. The impact induces a force and particle velocity at the top of the pile that can be measured using accelerometers and strain gauges. This paper discusses the theory behind using HSDT instruments and the procedures to calculate the capacity of the pile. The role of selecting the proper instrument to record them is also discussed. Finally, a case history involving the use of HSDT as an instrument for the observational method is presented