Seismic bearing capacity factor Nγe for dry sand beneath strip footing using modified pseudo-dynamic method with composite failure surface

2019 ◽  
pp. 1-10
Author(s):  
Kshitija Nadgouda ◽  
Deepankar Choudhury
Keyword(s):  
Bearing Capacity ◽  
Dynamic Method ◽  
Failure Surface ◽  
Strip Footing ◽  
Capacity Factor ◽  
Composite Failure ◽  
Dry Sand ◽  
Seismic Bearing Capacity ◽  
Bearing Capacity Factor

Seismic Bearing Capacity Factor Considering Composite Failure Mechanism

2018 ◽  
Vol 9 (1) ◽  
pp. 65-77
Author(s):  
Swetha S Kurup ◽  
Sreevalsa Kolathayar
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Static Analysis ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Shallow Foundation ◽  
Capacity Factor ◽  
Composite Failure ◽  
Seismic Bearing Capacity ◽  
Bearing Capacity Factor

This article describes how the design of shallow foundation needs complete knowledge about bearing capacity. During earthquakes additional lateral force acts at the foundation bed which reduces the bearing capacity. Most of the literature present either the pseudo static analysis or assume a planar failure surface to estimate seismic bearing capacity factors. Here, a pseudo dynamic approach that considers the time dependent effect of earthquake loading is employed. A composite failure surface has been considered for a more realistic estimation of seismic bearing capacity. New expressions were formulated to arrive at the seismic bearing capacity factor, considering the forces acting on the failure wedge based on the limit equilibrium approach. The effect of soil friction angles and the seismic peak of horizontal ground accelerations on the seismic bearing capacity were studied using the proposed method. It was observed that present pseudo-dynamic analysis with a composite failure mechanism gives lower values of seismic bearing capacity factors when compared to pseud- static analysis.

Pseudo-Dynamic Bearing Capacity of Shallow Strip Footing Resting on c-Φ Soil Considering Composite Failure Surface

2015 ◽  
Vol 6 (2) ◽  
pp. 12-34 ◽  
Author(s):  
Arijit Saha ◽  
Sima Ghosh
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Friction Angle ◽  
Strip Footing ◽  
Unit Weight ◽  
Composite Failure ◽  
Seismic Accelerations ◽  
Seismic Bearing Capacity

The evaluation of bearing capacity of shallow strip footing under seismic loading condition is an important phenomenon. This paper presents a pseudo-dynamic approach to evaluate the seismic bearing capacity of shallow strip footing resting on c-F soil using limit equilibrium method considering the composite failure mechanism. A single seismic bearing capacity coefficient (N?e) presents here for the simultaneous resistance of unit weight, surcharge and cohesion, which is more practical to simulate the failure mechanism. The effect of soil friction angle(F), soil cohesion(c), shear wave and primary wave velocity(Vs, Vp) and horizontal and vertical seismic accelerations(kh, kv) are taken into account to evaluate the seismic bearing capacity of foundation. The results obtained from the present analysis are presented in both tabular and graphical non-dimensional form. Results are thoroughly compared with the existing values in the literature and the significance of the present methodology for designing the shallow strip footing is discussed.

scholarly journals The Static and Seismic Bearing Capacity Factor Nγ for Footings Adjacent to Slopes

2016 ◽  
Vol 158 ◽  
pp. 410-415 ◽  
Author(s):  
Orazio Casablanca ◽  
Ernesto Cascone ◽  
Giovanni Biondi
Keyword(s):  
Bearing Capacity ◽  
Capacity Factor ◽  
Seismic Bearing Capacity ◽  
Bearing Capacity Factor

Seismic bearing capacity of a strip footing on rock slopes

2009 ◽  
Vol 46 (8) ◽  
pp. 943-954 ◽  
Author(s):  
Xiao-Li Yang
Keyword(s):  
Bearing Capacity ◽  
Failure Criterion ◽  
Strip Footing ◽  
Rock Slopes ◽  
Coulomb Failure ◽  
Coulomb Failure Criterion ◽  
Seismic Bearing Capacity ◽  
Earthquake Effects ◽  
Almost All ◽  
Bearing Capacity Factor

Most of the seismic calculations currently used for the evaluation of seismic bearing capacity are formulated in terms of a linear Mohr–Coulomb failure criterion. However, experimental evidence shows that a nonlinear failure criterion is able to represent fairly well the failure of almost all types of rocks. In this paper, a nonlinear Hoek–Brown failure criterion is used to estimate the seismic bearing capacity factor of a strip footing on rock slopes in a limit analysis framework. Quasi-static representation of earthquake effects using a seismic coefficient is adopted for the seismic bearing capacity calculations. A linear Mohr–Coulomb failure criterion, tangent to the nonlinear Hoek–Brown failure criterion, is used to derive the objective function that is to be minimized. Upper-bound solutions are obtained by optimization. For static problems, bearing capacity factors related to uniaxial compressive strength, Nσ, are compared. For seismic problems, Nσ factors for different ground inclinations are presented for practical use in rock engineering.

scholarly journals A numerical study of the bearing capacity factor Nγ

2001 ◽  
Vol 38 (5) ◽  
pp. 1090-1096 ◽  
Author(s):  
D Y Zhu ◽  
C F Lee ◽  
H D Jiang
Keyword(s):  
Bearing Capacity ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Shallow Foundation ◽  
Capacity Factor ◽  
Foundation Engineering ◽  
Base Angle ◽  
Bearing Capacity Factor

Values of the bearing capacity factor Nγ are numerically computed using the method of triangular slices. Three assumptions of the value of ψ, the base angle of the active wedge, are analyzed, corresponding to the following three cases: (1) ψ = ϕ, the internal friction angle; (2) ψ = 45° + ϕ/2; and (3) ψ has a value such that Nγ is a minimum. The location of the critical failure surface is presented and the numerical solutions to Nγ for the three cases are approximated by simple equations. The influence of the base angle on the value of Nγ is investigated. Comparisons of the present solutions are made with those commonly used in foundation engineering practice.Key words: shallow foundation, bearing capacity, bearing capacity factor, limit equilibrium.

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