Advancements in Statnamic Data Regression Techniques

Until recently, the analysis of Statnamic test data has typically incorporated the “Unloading Point Method” (Middendorp et. al, 1992) to determine an equivalent static capacity. The UP method requires that the foundation move as a rigid body, thus excluding stress wave phenomenon from the analysis. If this requirement is met the foundation capacity can be determined using this simplified method. However, many foundations do not meet the UP criteria (e.g. fixed end or relatively long piles) and have proven difficult to analyze without more complex techniques. This paper presents a new analysis method that uses measured strain data as well as the standard Statnamic test data to determine foundation capacity. This new method discretizes the foundation into smaller segments that each meet the rigid body criteria of the UP method. Thereby, a more refined inertia and viscous damping evaluation can be implemented that individually determines the contributions from the various segments. This approach, termed the “Segmental Unloading Point” (SUP) method, is developed herein and then demonstrated with results from full-scale Statnamic test data.