Push-out Strength of Concrete Plugs in Tubular Steel Piles

Investigations into the performance of concrete plugs in tubular steel piles under tension and compression have been conducted at Monash University over the past three years. The work presented in this paper reports the result of push out tests carried out on seven steel tubes specimens filled with reinforced concrete plugs with variable depths. Only one tube diameter, one concrete strength and one reinforcement arrangement was tested. The single variable was the length of the plug. Test results included the ultimate push-out forces, slip of concrete plugs, and longitudinal and hoop strains along the piles for some specimens. Strain measurements on the steel tube allowed the determination of shear transfer during the push out tests. The tests clearly showed that average bond strength achieved in compression significantly exceeds expectations and it is higher than the results of previous investigations using plugs without reinforcement. KEY WORDS: Tubular piles; composite behavior; offshor