Additions and replacements to existing superstructures, upgrading of structural loads and settlement or scour investigation all require the evaluation of existing foundations. Original pile installation records are often no longer available. Tethys tackles the challenges of unknown foundations on a routine basis. Tethys assesses the depth and evaluates the integrity of piles supporting existing structures by low strain integrity testing method (PIT), works well in certain soil-foundation conditions. In situations that require finding the length of existing steel piles (H-piles, Pipe piles, Cased Drilled Shafts, Steel Sheet Piles), When capacity determination is the issue Tethys perform a Wave Equation Analysis to select an adequate hammer to utilize for a Dynamic Load Test on a representative number of existing piles. The Dynamic Load Test gives sufficient information on pile capacity and integrity to aid the designer in the decision whether to reuse the piles. A detailed job report, including theoretical discussions of the methods and techniques employed, is issued shortly after the conclusion of the field tests.