Vertical Uplift Capacity of Rectangular and Square Plate Anchors in Granular Soil under Seismic Forces

Author(s):  
R. Ganesh ◽  
Jagdish Prasad Sahoo
2005 ◽  
Vol 42 (1) ◽  
pp. 263-271 ◽  
Author(s):  
Deepankar Choudhury ◽  
K S Subba Rao

Uplift capacities of inclined strip anchors in soil with a horizontal ground surface are obtained under seismic conditions. Limit equilibrium approaches with a logarithm-spiral failure surface and pseudostatic seismic forces are adopted in the analysis. The results are presented in the form of seismic uplift capacity factors as functions of anchor inclination, embedment ratio, angle of internal friction of the soil, and horizontal and vertical seismic acceleration coefficients. The uplift capacity factors are worked out separately for cohesion, surcharge, and density components. Use of the principle of superposition for calculating anchor uplift capacity is validated. The vertical seismic acceleration coefficient always reduces the uplift capacity, whereas the horizontal seismic acceleration coefficient reduces the uplift capacity in most cases. The roles of anchor embedment ratio, soil friction angle, and anchor inclination in determination of the seismic uplift capacity are also discussed. Comparisons of the proposed method with available theories in the seismic case are also presented. The present study gives the minimum seismic uplift capacity factors compared with the existing theory.Key words: seismic uplift capacity factors, inclined strip anchors, limit equilibrium, pseudostatic, c–ϕ soil.


Géotechnique ◽  
2021 ◽  
pp. 1-42
Author(s):  
Anamitra Roy ◽  
Shiao Huey Chow ◽  
Mark F. Randolph ◽  
Conleth D. O'Loughlin

2018 ◽  
Vol 46 (6) ◽  
pp. 801-816 ◽  
Author(s):  
M. Rahimi ◽  
S.N. Moghaddas Tafreshi ◽  
B. Leshchinsky ◽  
A.R. Dawson

2002 ◽  
Vol 39 (3) ◽  
pp. 648-664 ◽  
Author(s):  
K Ilamparuthi ◽  
E A Dickin ◽  
K Muthukrisnaiah

An experimental investigation of the uplift behaviour of relatively large scale model circular plate anchors up to 400 mm in diameter embedded in loose, medium-dense, and dense dry sand is described. Uplift capacity is strongly influenced by anchor diameter, embedment ratio, and sand density. In tests on shallow half-cut models, a gently curved rupture surface emerged from the top edge of the anchor to the sand surface at approximately ϕ/2 to the vertical, where ϕ is the angle of shearing resistance. For a deep anchor, a balloon-shaped rupture surface emerged at 0.8ϕ to the vertical immediately above the anchor and was confined within the sand bed. The load-displacement behaviour of full-shaped models was three-phase and two-phase for shallow and deep anchors, respectively. Alternative methods of determining the critical embedment ratio are considered, and values of 4.8, 5.9, and 6.8 are proposed for loose, medium-dense, and dense sand, respectively. Empirical equations are presented which yield breakout factors similar to those from many published laboratory and field studies.Key words: circular anchor, uplift capacity, sand, critical embedment ratio, failure mechanism.


1989 ◽  
Vol 29 (3) ◽  
pp. 138-144 ◽  
Author(s):  
Braja M. Das ◽  
Vijay K. Puri
Keyword(s):  

Author(s):  
Anamitra Roy ◽  
Shiao Huey Chow ◽  
Conleth D O'Loughlin ◽  
Mark F. Randolph

his paper investigates the uplift capacity of horizontal plate anchors in sand through finite element analyses and centrifuge experiments. Finite element simulations adopt a sophisticated bounding surface plasticity model that accounts for stress and density dependent behaviour, as well as loading and fabric related anisotropic effects in sands. Failure mechanisms at peak anchor capacity show that failure occurs progressively, with a marked decrease in mobilised friction angle within the shear bands close to the anchor edge. Numerical simulations of a large set of centrifuge experiments on rectangular, strip and circular plates at different relative densities and stress levels are in good agreement for dense conditions, but perform poorer for loose conditions due mainly to the open cone yield surface in the bounding surface model. Equivalent comparisons with current limit equilibrium methods highlight the challenges in direct application of element level strength equations. Finally, the paper proposes a modified limit equilibrium solution based on a ‘rigid-block’ failure mechanism extending to soil surface, but with anchor factors that encompass the results from the finite element simulations. The modified solution provides a higher level of agreement with results from a large database of plate and pipeline test data than existing limit equilibrium methods.


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