Seal slab/steel pile interface bond from full-scale testing

This paper presents results front model and full-scale tests to assess the interface bond between a cast-in-place concrete seal slab and steel H-piles in cofferdams. Three different seal slab placement conditions-fresh water salt water, and bentonite slurry-were evaluated and the results were compared against controls where no fluid was displaced by the concrete. Normal pile surfaces were investigated. Additionally, the situation of soil-caked piles was also tested. In the model tests, eight 15 cm deep, W6 x 15 sections were used for two different embedment depths of 1.5d and 2d, with d being the depth of the section. In the full-scale tests, 16 specimens 35 cm deep (W14 x 90 sections) were tested with the embedment varied between 0.5d and 2d. The results show that significant bond stresses developed even in the worst placement condition. Recommendations made for revising current values in specifications have already, been implemented by, the Florida Department of Transportation.