Strength and Behavior of Grouted Pile‐To‐Sleeve Connections

Abstract

Eighteen grouted pile‐to‐sleeve connections were tested to examine the influence of combined loading, relative shear‐key location between pile and sleeve, pile‐sleeve eccentricity, and grout strength. The results indicated that combined loading had no detrimental effect on ultimate capacity of a grouted connection. Ultimate capacity was not affected by the position of shear keys in the pile relative to those in the sleeve or by thickness variations in the grout annulus. The capacity of connections varied with the square root of the grout strength. Results were compared with recognized empirical formulations. The results indicated that safety factors could be reduced and yet maintain acceptable safety indices. Examination of tested grouted‐connection specimens indicated that the major load‐resisting mechanisms are grout commpression struts and friction that develops at the grout‐steel interface. A simplified analytical model was developed using concrete constitutive relationships, and various geometric and material parameters were investigated. The analytical results indicated that increases in shear‐key height or reduction of shear‐key spacing may not lead to higher ultimate strength of the connection.