Experimental Evaluation of Engineering Properties of GFRP Screw Anchors for Anchoring Applications

Abstract

Steel screw anchors (SSAs) have been widely used in geotechnical engineering practice because they are simple in structure and easy to design and construct. The main disadvantage of SSAs is that they rust quickly and are not found to be suitable for permanent structures, unless adequate corrosion protection measures are provided. Anchors made of glass fiber–reinforced plastic (GFRP) are corrosion-resistant material that are light in weight with a higher tensile resistance in comparison with SSAs. For this reason, GFRP anchors have been found to be a good substitute for SSAs during the last two decades. In this paper, details of a newly developed GFRP screw anchor (GFRP-SA) with respect to the physicomechanical, tensile, and creep properties along with its performance both in the laboratory and in field conditions are provided. A specially developed machine that facilitates quick installation of the GFRP-SA is also briefly introduced. In addition, two full-scale field tests that were undertaken to study in situ long-term performance of the GFRP-SAs for anchoring soil slopes (1) in an expansive soil, and (2) in a compacted subgrade soil are presented and discussed. Furthermore, the average pullout resistances of the GFRP-SAs were also determined from field tests. The results of the field studies suggest that GFRP-SAs can be installed with relative ease and they provide adequate resistance against shallow landslide slope failures. The study presented in this paper is encouraging for the use of GFRP-SAs in conventional geotechnical engineering practice for stabilizing slopes in different types of soils.