Pullout Resistance of Tapered Metal Straps in Fills with High Fines Contents

Abstract

Mechanically stabilized earth-retaining walls (MSEWs) have been widely used in construction and transportation projects. Most codes and guidelines require that the soil used as backfill for MSEWs have fines contents lower than 15% to ensure adequate reinforcement pullout capacity, drainage, and soil stiffness. To use higher fines contents, an understanding of the factors influencing the pullout resistance of the reinforcing elements is crucial for an appropriate design. In this paper, a series of laboratory pullout tests has been conducted to investigate the potential of tapered steel straps with a wedge-shaped tail to enhance the pullout resistance in silty sands with up to 60% nonplastic fines. The pullout capacity was strongly influenced by the dilation angle, which was critically dependent on the silt content and the stress level. For all the tested silty sands, the pullout resistance of the tapered straps was higher than the resistance of rough flat straps, and this enhancement in the resistance increased slightly with the rise of the fines content.