Behavior of pile caps on one steel pile

Abstract

Piles are slender linear structural elements, whose purpose is to transfer the load from the superstructure to the soil. The connection between the piles and the superstructure is commonly done by pile caps that, according to the NBR 6118, are volumetric structures used to transfer the load coming from the superstructure to the piles. The first studies of great relevance, regarding the design of pile caps, are from Blévot & Frémy1 however, most of the researches on this area studied pile caps on reinforced concrete piles, leaving a vast field to be explored about pile caps on steel piles. According to Velloso & Lopes,2 the main disadvantage of using steel piles, in relation to other types of piles, is its high cost. Still, in some situations the use of steel piles is economically viable as they can be driven in almost any kind of soil and are highly effective against the vibration on the driving process. In agreement with NBR 6122,3 connection between the pile and the cap can be made with an embedment length of the pile in the cap of 20 centimeters and, in addition, a helical reinforcement may be used. After its review, the NBR 61224 suggests only that the connection must be made by using either steel plates on top of the piles, stirrups or steel rebar welded to the pile. Fundações Teoria e Prática5 recommends that a helical reinforcement is placed over the embedment length of the steel pile in the cap. Pfeil6 suggests that straight rebar must be welded over the embedment length of the steel pile, with the addition of helical reinforcement, and that the embedment length of the steel pile must be at least 30 centimeters.