Volume 34, N. 1

January-April 2011

Effects of the Construction Method on Pile Performance: Evaluation by Instrumentation. Part 2: Experimental Site at the Faculty of Engineering of the University of Porto

Article

Volume 34, N. 1, January-April 2011 | PDF (0 downloads)

Abstract

Three different types of piles (bored, CFA and precast driven) were installed in the experimental site located in the Campus of the Faculty of Engineering of the University of Porto to study the effects of the construction method on pile performance. The subsoil is a residual granitic soil reaching depth levels over 20 m. In this site, several field and laboratory tests were conducted to obtain the local geotechnical parameters. Static pile load tests with load-unload cycles were performed. Bored and CFA piles were instrumented along the depth, with installation of retrievable sensors; a flat-jack load cell was inserted at the bottom of the bored pile. Load tests results demonstrated that bored and CFA piles show similar behavior: i) the applied load reaching the pile tip was about 42%, ii) and the average mobilized lateral resistance was about 60 kPa. After the tests were completed, piles were extracted for further inspection of shaft and load cell conditions. The driven pile although having a smaller cross-section showed a stiffer response and higher resistance than the other two piles, which are a clear indication that the installation effects play an important role in the pile response. The results are compared to those obtained in Part 1 of this article relating to tests performed at the Experimental Field of Unicamp (State University of Campinas).

Keywords: construction technique, bored pile, CFA pile, precast pile, instrumentation, granitic residual soil,


Submitted on February 04, 2010.
Final Acceptance on September 20, 2010.
Discussion open until August 31, 2011.