Effect of lateral movement type on earth pressures developed behind the abutment of a semi-integral bridge

Resumo

Semi-integral abutment bridges are constructed without thermal expansion joints, and the
superstructure-abutment system is not integrally connected to the substructure. In view of this peculiar
characteristic, the abutment undergoes combined movements of translation and rotation due to the expansion and
contraction of the superstructure. This work proposes to analyze the effect of different lateral movements on the
earth pressures developed behind the abutment of a semi-integral bridge. Numerical simulations were carried out
by using a finite element model. Lateral movements of the abutment were simulated in three different conditions:
combined rotation and translation (Case 1), rotation only (Case 2), and translation only (Case 3). Predicted lateral
earth pressures were compared with experimental field data obtained from a semi-integral bridge abutment.
Predicted values were obtained at the same position where the field measurements were performed on the
abutment. The best match between field and numerical pressures were obtained with Case 1. During expansion
phases of the bridge superstructure, Case 2 slightly underestimated the lateral earth pressures, while Case 3
overestimated them. The opposite occurred during contraction phases. The combined movement of rotation and
translation proved to be more suitable to represent the lateral movements of the bridge abutment in field conditions.