This paper presents results from 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 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, 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-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.
Author: Gray Mullins, Ruben Sosa, Rajan Sen & Moussan Issa, University of South Florida
Publisher: DFI