Numerical Study of an Integral Abutment Bridge Supported on Drilled Shafts |
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Authors: | Phillip S K Ooi Xiaobin Lin Harold S Hamada |
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Affiliation: | 1Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Hawaii, Holmes Hall 383, 2540 Dole St., Honolulu, HI 96822 (corresponding author). E-mail: ooi@eng.hawaii.edu 2Former Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Hawaii, 2540 Dole St., Honolulu, HI 96822. E-mail: xiaobin@hawaii.edu 3Emeritus Professor, Dept. of Civil and Environmental Engineering, Univ. of Hawaii, Holmes Hall 383, 2540 Dole St., Honolulu, HI 96822. E-mail: hamada@eng.hawaii.edu
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Abstract: | The majority of integral abutment bridges (IABs) in the United States are supported on steel H-piles to provide the flexibility necessary to minimize the attraction of large lateral loads to the foundation and abutment. In Hawaii, steel H-piles have to be imported, corrosion tends to be severe in the middle of the Pacific Ocean, and the low buckling capacity of steel H-piles in scour-susceptible soils has led to a preference for the use of concrete deep foundations. A drilled shaft-supported IAB was instrumented to study its behavior during and after construction over a 45-month period. This same IAB was studied using the finite-element method (FEM) in both two- (2D) and three dimensional (3D). The 3D FEM yields larger overall pile curvature and moments than 2D because in 3D, the high plasticity soil is able to displace in between the drilled shafts thereby “dragging” the shafts to a more highly curved profile while soil flow is restricted by plane strain beam elements in 2D. Measured drilled shaft axial loads were higher than the FEM values mainly due to differences between the assumed and actual axial stiffness and to a lesser extent on concrete creep in the drilled shafts and uneven distribution of loads among drilled shafts. Numerical simulations of thermal and stream loadings were also performed on this IAB. |
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Keywords: | Bridge abutments Drilled shafts Finite element method Thermal factors Earth pressure Axial loads |
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