DFI Announces New, Free Publications Based on Research Projects
DFI announces three new publications available at no cost from the Publications Store at www.dfi.org. The publications are deliverables from research projects supported by the DFI Committee Project Fund and in-kind contributions. The Committee Project Fund was established in 2011 to fund DFI Technical Committee projects that advance the state of practice and understanding of deep foundations and produce a usable deliverable.
Guide to Tremie Concrete for Deep Foundations, 2nd Edition: The primary purpose of this report—published by the EFFC and DFI Concrete Task Group—is to provide guidance for characterization related to performance, mix design process, and methods used to test fresh concrete. The principles of this guide apply to tremie concrete for deep foundations but may also be applied for other forms of deep foundations (e.g., continuous flight auger piling). The guide addresses design considerations including concrete rheology, mix design, reinforcement detailing, concrete cover, and good practice rules for placement. A review of methods to test the as-built elements is presented together with advice on the identification and interpretation of the results.
Influences of Mixture Proportions and Test Conditions on the Strength and Stiffness of Wet-Mixed Soil and Cement: Establishing a suitable mix design is important to provide the engineering property values necessary for adequate performance of a deep mixing support system. The mix design process often includes a laboratory mixing program to identify suitable binder types and appropriate mixture proportions. The objectives of this research were to investigate: (1) the influences of laboratory procedures and test conditions on measured property values of cement-treated soil, (2) relationships between engineering property values, such as the relationship between unconfined compressive strength and Young’s modulus, and (3) the influence of mix design proportions on cured strength and on mixture consistency immediately after mixing.
ACIP Pile Installation, Installation Monitoring, Full-scale Load Testing and Extraction Program: DFI’s Augered Cast-In-Place (ACIP) Pile Committee performed a foundation installation, monitoring, performance and extraction program for ACIP piles in the fall of 2016. The purpose of the project was to demonstrate a fully monitored installation of instrumented 18 in (457 mm) and 24 in (610 mm) diameter ACIP piles, including automated monitoring equipment (AME); post-installation thermal integrity profiling (TIP) measurements; compression, tension, and lateral load testing (including monitoring of strain gages embedded along the compression pile shaft); and post-testing extraction of an installed pile for visual inspection.