High strain dynamic pile testing in a challenging soil condition – A case study in Southern Alberta, Canada Pirahas Balasingam, Pedram Roshani & Jason Jagodich Morton & Jagodich Incorporated, Calgary, AB, Canada ABSTRACT Driven piles are increasingly utilized as foundation elements in challenging geotechnical conditions that have where drilled shafts would have been deemed appropriate. Predicting driven pile performance and capacity can be a daunting task. Unique soil conditions or variation across the subsurface of a project site can add further challenges to predicting performance of driven piles. High strain dynamic pile testing provides a fast, effective, and economical quality control tool for the installation of driven piles. This paper describes the application of High strain dynamic testing in performance evaluation of driven piles installed in a very dense sand ground condition in southern Alberta, Canada. The project site is located in the vicinity of Fort MacLeod, Alberta. Site conditions and pile installation process are described in detail. Pile instrumentation, test procedures, and PDA test results and their relevancy are discussed in detail. The results of CAse Pile Wave Analysis of Program (CAPWAP ® ) are discussed comprehensively in order to provide baseline conclusion that can be used in future for analysis of driven piles with similar soil conditions. A characteristic load settlement curve was developed for driven piles installed in very dense sand using the results of CAPWAP analysis performed on eighty two piles. RÉSUMÉ Les pieux battus sont de plus en plus utilisés comme éléments de fondation dans des conditions géotechniques difficiles où leurs pendant vissés auraient historiquement été considérés appropriés. Prédire les performances du pieu et sa capacité peut s’avérer une tâche ardue. Des conditions uniques ou une grande variabilité des propriétés du sol d'un site peuvent significativement complexifier la prédiction des performances. Les essais de chargement dynamiques de pieux à grande déformation fournissent une méthode de contrôle rapide, efficace et économique lors de l’installation de pieux battus. Ce document décrit l’utilisation de l’analyseur de battage de pieux (PDA) dans l'évaluation de la performance des pieux battus installés dans un sol en argile raide dans le sud de l'Alberta, Canada. Le site du projet est situé dans les environs de Fort MacLeod, en Alberta. Les conditions du site et le processus d'installation des pieux sont décrits en détail. L’instrumentation des pieux, les procédures d'essai et les résultats des tests PDA et de leur pertinence sont discutés en détail. Enfin, une analyse CAse Pile Wave, réalisée en utilisant le logiciel CAPWAP®, est présentée en détail afin de fournir une conclusion de référence qui pourra être utilisée pour l'analyse des pieux battus dans des conditions de sol similaires. 1 INTRODUCTION High-strain dynamic testing of piles (ASTM D4945) has been conducted for more than 40 years. The first pile driving analyzers (PDA) were simple analog computers without storage capability. Over the past few decades significant advancement has been made on the understanding of and testing of deep foundations. PDAs have also evolved considerably and are now made with flexible digital microcomputers with significant internal storage capacity, wireless connectivity, and graphic display. However, even though some new parameters have been added, the basic equations used to calculate the bearing capacity of the test piles are still the same. The concept of this testing procedure is to apply massive dynamic impact on the element and convert the resultant into static capacity. The basic purpose of high strain dynamic pile testing is to evaluate pile static capacity and its structural integrity using measurement of both force and velocity. CAse Pile Wave Analysis Software (CAPWAP) is utilized to analyze the field data (interpret the dynamic wave) and conduct the conversion into the required pile capacity. The method involves attaching a minimum of two pairs of strain transducers and accelerometers on diagonally opposite sides of the pile. These are fixed minimum two (2) times the pile diameter below pile top. Impact is generated using a hammer capable of delivering the required impact to achieve the target load. The load and height of drop is pre-calculated using the soil parameters using GRL Wave Equation Analyses and Drivability Studies (WEAP) analysis. The strain transducers attached to the pile measure the strain on the piles during impact, whereas accelerometers record the accelerations generated in the pile.