SuperPile 2017 Online Proceedings, (DFI)
Optimization of Deep Foundation Design & Construction through Establishment of Site-Specific Ultimate Foundation Capacities
Seth H. Hamblin, P.E.
Deep foundation design solutions are often developed in the absence of a comprehensive site-specific load testing and integrity evaluation program where foundation elements are tested to their ultimate capacity, or failure. Primarily due to schedule and budgetary limitations, and design code requirements, executing deep foundation load tests to failure is typically replaced by performing ‘proof tests’ which only serve to evaluate design assumptions developed through predominantly conservative static design approaches. The result of this frequently used methodology within the deep foundation industry is suboptimal and more expensive foundation systems. The presentation demonstrates examples of successful projects that have departed from the traditional methodology described above and highlights the numerous advantages of replacing ‘proof testing’ with full scale load testing to develop ultimate foundation capacities and optimize foundation design. The results of several case studies will be presented, each highlighting a different deep foundation type, where a comprehensive and pre-planned deep foundation load testing program was performed to establish ultimate capacities prior to the selection and final design of the structures. The results obtained from each program were incorporated into the development of the final design and ultimately produced significantly more economical and higher capacity foundations, while also expediting the foundation installation schedule. Obstacles within the industry which limit implementation of full scale testing will also be examined. We hope that exhibiting meaningful examples of load testing to failure and highlighting current impediments will create discussion within the industry which leads toward wider implementation of ultimate load testing programs by both Engineers and Contractors.
|article #2668; publication #1031 (SP-2017)|