Integrity testing of concrete deep foundation with focus on thermal methods

Simon Gudina

In the proceedings of: GeoSt. John's 2019: 72nd Canadian Geotechnical Conference

Session: Pile Foundations

ABSTRACT: Integrity test methods for concrete deep foundations are reviewed. The most common and traditional non-destructive evaluation or quality assurance for concrete foundations have been methods involving Cross-hole Sonic Logging (CSL) or its variant, Single-hole Sonic Logging (SSL), Gamma-gamma Logging (GGL), Sonic Echo (SE), and Impulse Response (IR). The latter two are generally known as Pile Integrity Testing (PIT) method. These conventional tests are generally carried out several days after completion of pile installation. In the last several years, a new quality assurance method for cast in place concrete deep foundations has been developed. It is based on concrete thermal behavior (concrete hydration) to assess the integrity of installed concrete deep foundations. This latest method is known as Thermal Integrity Profiling (TIP) and is covered in ASTM D 7949: Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations. Despite being a very recent development, TIP has been gaining widespread acceptance as a quick quality assurance method for concrete deep foundations. TIP test results can be available as early as 24 hours after concrete placement. Traditional and TIP methods are discussed with respect to their relative advantages and limitations. Current trends and status of TIP method in the USA, specifically with respect to state Departments of Transportation (DOTs) is reviewed. Finally, two case studies involving TIP testing are presented showing the effectiveness of the method in providing quality assurance at a very early stage and hence contributing to a timely completion of pile installation and subsequently to timely project completion.

RÉSUMÉ: Les méthodes de test d'intégrité pour fondations profondes en béton sont passées en revue. Les méthodes les plus méthodes de journalisation sonique à trous croisés (CSL) ou sa variante, la journalisation sonique à un trou (SSL), la journalisation gamma-. Ces tests classiques sont généralement qualité pour les fondations profondes en béton coulé sur place a été mise au point. Il est basé sur le comportement thermique du béton (hydratation du béton) afin d'évaluer l'intégrité des fondations profondes en béton installées. Cette D 7949: les fondations profondes en béton. Les résultats du test TIP peuvent être disponibles dès 24 heures après la mise en place du béton. Les méthodes traditionnelles et TIP sont discutées en fonction de leurs avantages et limites relatifs. Les méthode TIP aux États-Unis, en particulier en ce qui concerne les États DOT, sont passés en revue. Enfin, deux études de cas impliquant des tests TIP sont présentées, montrant l'efficacité de la méthode pour fournir une assurance qualité à un stade très précoce, contribuant ainsi à l'achèvement en temps voulu de l'installation des pieux et ensuite à l'achèvement du projet. 1 INTRODUTION Integrity testing is a non-destructive evaluation method used to assess the quality of cast-in-place concrete deep foundations. These methods compare the homogeneity or uniformity of the tested foundation element. In general, integrity tests are meant to detect zones of defect (i.e., anomaly) either due to reduced cross-section or due to inferior quality material. Integrity test methods may involve techniques based on acoustic echo, ultrasonic cross hole, gamma-gamma, or thermal logging procedures. Integrity tests are generally used for quality assurance of newly constructed concrete deep foundations; they can also be used to evaluate the condition of existing foundations (Rausche 2004). This article reviews only those methods used for the quality assurance of newly constructed concrete deep foundations. While integrity testing can be used for both cast-in-place and driven piles, this article considers the former only. 1.1 Integrity testing versus pile load testing As opposed to most pile load tests, integrity tests are non-destructive by nature and will not result in a change in load carrying capacity of the element tested. Integrity tests do not measure load carrying capacity of tested foundation elements but indicate the existence of defects, etc. In general, pile load tests measure the ultimate load carrying capacity; integrity tests yield results that are general indicators of performance but do not provide quantitative measure of performance.

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