Performance of helical soil-nailed walls under bridge abutment

Abstract

In the current study, the performance of helical soil-nailed walls (HSNWs) was evaluated under bridge abutment using reduced-scale model tests. For this purpose, sixteen wall models were constructed with different lengths, patterns and inclinations of the helical nails and then were loaded to failure using the strip footing. Findings indicated that 15° can be introduced as the optimal inclination for installing helical nails in walls under bridge abutments to achieve the maximum bearing capacity and minimum lateral wall displacements. It was found that although using longer nails and installing them in a square pattern and optimal angle reduced the penetration depth of the slip surface, but caused more portion of the bridge footing pressure to be converted to connection load and, consequently, bending in the wall facing. Moreover, the role of the lower rows of nails in the stability of HSNWs was found to be more prominent than the upper rows. Also, it was concluded that the method proposed by FHWA [1] to calculate the connection load could be used as an upper bound in helical soil-nailed walls under bridge abutment.