Structural performance of a proposed UHP-FRC shield in harsh environment

Hamed, Mohamed (2018) Structural performance of a proposed UHP-FRC shield in harsh environment. Masters thesis, Memorial University of Newfoundland.

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Abstract

Offshore structures are used in harsh ice-infested environments. Shields for such structures are necessary to protect them from ice abrasion. An ice shield is proposed using ultra high performance fibre reinforced concrete (UHP-FRC). This type of concrete is attractive due to its high abrasion resistance that would be beneficial to protect the structure from ice-wear. In order to examine the interaction between the ice shield and the offshore structure, composite flexural and shear specimens were investigated in this thesis. Ten flexural specimens were cast and tested. All specimens were made with two layers of concrete. The top layer was UHP-FRC and the bottom layer was high performance fibre reinforced concrete (HP-FRC). The parameters tested were the thickness of the top layer (50 mm and 75 mm), the spacing between the shear connectors (390 mm and 195 mm), and the type of shear connectors (shear keys and T-headed studs). The structural behaviour of the specimens was examined in terms of crack development, specimen deformation, strains in steel and concrete, horizontal shear slip and capacity, and ultimate capacity. The results revealed that the thickness of the top layer did not have a significant effect on the serviceability behavior of the specimens. However, increasing the thickness led to an increase in the ultimate capacity. The specimens with 390 mm spacing between the shear keys were unable to develop a full composite action and had an interface failure. The specimens with T-headed studs and 195 mm developed fully composite action with high ductility. Direct shear specimens were also cast and tested. The shear specimens duplicated the interface geometry of the flexural specimens and had the same parameters. The results of the direct shear tests were compared to the predictions of different code and some proposed equations in the literature. The results of the comparison revealed that most code and proposed equations can adequately predict the interface capacity of the composite specimens. In addition, the interface shear capacity of both the flexural and the direct shear tests were compared. It was concluded that the shear specimens yielded higher shear capacity than the flexural specimens for the specimens with shear keys that failed due interface failure.

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