DEVELOPMENT OF AN ANALYTICAL MODEL FOR THE ULTIMATE CAPACITY OF AXIALLY LOADED GROUTED PILE TO JACKET CONNECTIONS
BLANFORD, MARK LEWIS
Doctor of Philosophy
Steel offshore platforms are typically connected to their foundation pilings by injecting cement grout in the annulus between each pile and its sleeve. In the last few years a good deal of experimental study had contributed to a rational understanding of the design of these grouted connections; however, very few analytical results have accompanied this effort. In the present investigation a mathematical model is developed to simulate the mechanical response of a grouted connection to monotonically increasing axial loads. When shear lugs are included to increase the load capacity of the connection, the local behavior of the grout at the lugs strongly influences the response. A modest experimental program was conducted to study the crushing-type failure of the grout beneath the lugs, and an analytic formulation is proposed which relates the lug load-displacement history to the grout cube strength and volumetric porosity. The predictions of the model are compared with experimental load-deflection curves, and trends resulting from the variation of design parameters are studied. This analysis adequately predicts the measured behavior of grouted connections in many respects, and identifies areas in which further study should be concentrated.