Comparison of Pile Driving Equations

Abstract

In Sri Lanka, remote highway projects, driven piles are installed in large quantities mainly as a ground improvement where the soft soil thickness is very high and closer to the bridges to decrease the settlements. In building sector as well, the installation of the driven piles are very common to decrease the foundation construction time and has seen the installation of driven piles as the settlement reduction means. Recently, silent pile installation technology has increased and the Sri Lankan investors has invested large sum of money for the silent hammers. Capacities of the piles can be estimated using the pile driving equations during installation of the piles. This is very convenient to determine the capacities of the piles without performing a pile load test. On the other hand, this can be reducing the site investigation requirements to a minimum. As the capacities of the piles are estimated during installation, it can take into account in-situ subsurface conditions. The rapidly varying ground conditions, especially in Sri Lanka, or any other location, can be captured by pile driving records. Recently, especially in Sri Lanka, the installation of the PHP piles with a hollow area at the middle of a pile section has increased. The design community multiplies the area of the pile cross section by the end bearing capacity to obtain the end bearing force whether it is a PHP pile or a solid pile. This research will compare the pile driving equations with each other and select the best pile driving equations which predict the capacity very close to the measured capacity as an extension of the earlier research done by Thilakasiri and Jayaweera (2009). In addition the mobilization of the end bearing capacities in PHP piles with a hollow area at the middle of a pile section is compared with a solid pile and a relationship is derived to predict the capacity of the hollow area as a function of the hollow area as a percentage of the total area of the pile cross section.