An experimental investigation for pullout response of a single granular pile anchor in clayey soil

Hans Raj Vashishtha,Vishwas A Sawant

doi:10.1186/s40703-021-00162-3

Hans Raj Vashishtha, Vishwas A Sawant

Open Access

https://doi.org/10.1186/s40703-021-00162-3

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Abstract

The granular pile anchor foundation is an effective and economical foundation system to counter the pullout forces exerted in case of transmission towers or foundations in expansive soil. The pullout tests were performed to study the behaviour of a single granular pile anchor in the clayey soil bed. Tests were conducted in a steel tank of 1 × 1 × 1 m size with the help of loading frame arrangement. The pullout load required for upward movement equal to 10% diameter was considered as the pullout capacity of the granular pile anchor. In the parametric study, length and diameter of the granular pile anchor were varied to examine their effect. Number of anchor plates was also varied in few tests. The pullout capacity enhanced with an increase in the diameter and length to diameter ratio. The effect of the length to diameter ratio was appreciable up to the value of 10. However, no significant effect was found in the cases of multiple anchor plates. A relationship is proposed to predict normalized pullout capacity.

Highlights

Concurrent with the development of communication networks during the recent years, many mobile communication towers have embarked at various places
The graphs were prepared between upward movement on the x-axis and pullout loads (N) on the y-axis after conducting the pullout test to study the pullout behaviour of the granular pile anchor (GPA)
The curves reflect the effect of the length to diameter (L/D) ratio on the pullout capacity of a 75 mm diameter single GPA

Summary

Introduction

Concurrent with the development of communication networks during the recent years, many mobile communication towers have embarked at various places. These transmission towers are subjected to significant wind loads. It generates uplift forces on the foundations on one side and compression on the other side. The granular pile anchor (GPA) foundation system is an effective and economical foundation system to resist the pullout forces. A mild steel plate of same diameter as granular pile is devised as anchor plate This anchoring arrangement through anchor plate and anchor rod enables the GPA to offer resistance towards the pullout forces.

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Conclusion