Managing the requirements for drilled pile tips

Abstract

Load bearing drilled piles, especially drilled piles whose casing becomes a part of the pile, have been developed and researched in Finland extensively since the 90’s and they have become a common solution in difficult deep foundation projects in Northern Scandinavia. Although the Eurocodes do not currently feature the design of drilled piles, there exist relevant national building codes in countries using them. However, drilled pile tips are only briefly mentioned in them, although they usually form a load bearing part of the drilled piles and have a critical effect on their performance. This thesis aims to research all the relevant legislative and practical requirements for drilled pile tips in load bearing piles and present them in a clear and concise manner. The main areas of interest were the legislative and practical load bearing and manufacturing requirements for drilled pile tips, the welding joints between pile casings and casing shoes, and the current situation with the CE-marking in relation to drilled pile tips. The objectives were achieved by researching the legislative and instructive literature about drilled piles and their design. Extensive research had to be done to locate and analyse all the relevant laws and regulations, because in many European countries, Finland included, the regulations are still in a state of slight disarray with the new Eurocode system overlapping with the old national building codes. In addition to this literary research, some expert interviews were also conducted to better understand the legislative and practical requirements that have not been explicitly stated. Other sources, such as previously done theses, were also searched for relevant information, although they only provided a very limited amount of relevant information. Finland was chosen as the main geographical focus point due to the popularity of drilled piles here. Furthermore, the Finnish national annexes and guides are sufficiently similar to the design in other countries that use drilled piles, mainly Sweden and Norway, that the conclusions drawn are generally valid in them also. The main results of this thesis were the suggestions concerning the design of drilled pile tips, the welding splice of the casing shoes and the voluntary CE-marking of drilled pile tips. This thesis will also function in the future as an introduction to drilled piles and their design in Finland.