Comparison of Uplift Capacity and Nonlinear Failure Surfaces of Single-Belled Anchor in Homogeneous and Layered Sand Deposits

Tanaya Deb,Sujit Kumar Pal

doi:10.1155/2019/4672615

Abstract

This experimental study explains the contribution of embedment ratios, diameter ratios, and bell angles to uplift capacities of single-belled anchors and formation of nonlinear failure surfaces in homogeneous and layered sand deposits. Uplift capacities in both types of sand deposits are increased with higher embedment ratios, lesser diameter ratios, and bell angles. Uplift capacities are higher in layered sand deposit in comparison with homogeneous sand deposit for the same model. Analytical uplift capacities are predicted by the horizontal slice method based on observed failure surfaces. A comparative discussion is made on nonlinear failure surfaces as well as analytical uplift capacities in reference to aforementioned parameters for the variation in sand deposits. The 45° and 63° belled anchors are more effective as uplift-resistant structures than 72° anchors in both types of sand deposits. Out of 36 analytical data on homogeneous sand and 33 analytical data on layered sand, 94.45% data are within the range of +08.51 to −10.70% and 100% data are within the range of +10.47 to −10.72%, respectively, with respect to the experimental uplift capacities. Four numbers of multiple linear regression models have been developed by observed breakout factors to eliminate the size effect, so the newly developed models are suitable for actual engineering to compare with prototype tests within the suggested imitation of values of variable parameters.

Highlights

For radar tower, television line tower, power pole, roadside sign posts, and outdoor sign pools, imbalance horizontal forces mainly due to severe wind velocity and resultant uplift load are more than their self-weight
Kumar [22] conducted a numerical study on uplift resistance of circular and strip anchor where failure mechanism was explained by velocity hydrograph
All the experimental data of Qu(SI) and Qu(SII/Sand I (SI)) for each 3D models are shown in Table 4 (column (ii) and (vi), respectively) facilitate to compare uplift behaviour of belled anchors in SI and Sand II (SII)/SI deposits in reference to variation in L/Db, L/Db, and β

Summary

Introduction

Television line tower, power pole, roadside sign posts, and outdoor sign pools, imbalance horizontal forces mainly due to severe wind velocity and resultant uplift load are more than their self-weight. Peck et al [1] reported that piles are often used specially to resist tensile forces beneath several common types of structures such as towers, gas storage tanks, and tall stacks; beneath such structures, the tensile forces are always caused by the moment due to wind In such structures, the expected uplift load and overturning moments are basic design considerations to ascertain their types, shapes, and sizes. Sakai and Tanaka [23] presented pictorial view of failure mechanism in two-layered sand, where medium dense and loose sands were overlying dense sand and vice versa. These studies are performed on plate anchors only. Till the Advances in Civil Engineering date, studies on the uplift behaviour as well as nonlinear failure behaviour on belled anchors in higher-dense sand overlying lesser-dense sand have yet been lacking

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