Construction-Induced Stresses in H-Piles Supporting an Integral Abutment Bridge

Although the advantages of integral abutment bridges are widely known, design practices and assumptions vary extensively, especially when bridges have skew. Some agencies explicitly calculate bending effects on piles, but many do not consider the dead load bending. Piles traditionally have been required to be deep enough in soil to achieve fixity. The monitoring of the performance of a skewed integral abutment bridge on shallow bedrock in Coplin Plantation, Maine, during construction is reported. The sequence and procedure of construction was analyzed to assess its effects on stresses in the pilings. Stresses from bending in the direction of the centerline were equal to or greater than stresses from axial loading of the piles. These stresses were related to rotation of the abutment caused by dead loads. Stresses from bending perpendicular to the roadway centerline were apparently related to the skew and were less than one-third of the bending parallel to the centerline. Axial loads and maximum stresses varied among piles, although skew effects and pile foundation fixity differences accounted for some, but not all, variability. Maximum stresses were less in the piles without fixity; this indicates that construction loadings support the feasibility of designing integral abutment piling without fixity.