An alternative to the Mononobe–Okabe equations for seismic earth pressures

Mylonakis, George; Kloukinas, Panos; Papantonopoulos, Costas

doi:10.1016/j.soildyn.2007.01.004

Cited by 157 publications

(72 citation statements)

References 14 publications

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“…In comparison, the M-O solution and the Mylonakis et al (2007) solutions are considerably higher than measured values at accelerations above about 0.4 g. The equivalent seismic earth pressure, computed using the prototype structure dimensions, clearly exceeds all other results by a considerable margin, as would be expected based on the assumptions used in deriving this solution , as discussed in section 2.5.1. The data also show that the seismic earth pressure increments increase with depth consistent with static earth pressure distribution and consistent with that implicit in the M-O solution which forms the upper bound for the experimental results.…”

Section: Discussionmentioning

confidence: 65%

“…Similarly, the envelope suggested by Al-Atik and Sitar (2010) represents a reasonable upper bound for dynamic earth pressure increment on displacing, cantilever retaining walls. In comparison, the M-O solution and the Mylonakis et al (2007) solution are considerably higher than measured values at accelerations above about 0.4 g. The equivalent seismic earth pressure, computed using the prototype structure dimensions, clearly exceeds all other results by a considerable margin, as would be expected based on the assumptions used in deriving this solution which were discussed at section 2.5.1.…”

Section: Dynamic Lateral Earth Pressures Observed In Centrifuge Expermentioning

confidence: 66%

“…A recent alternative to the M-O method for plastic soils was developed by Mylonakis et al (2007). They proposed a closed-form stress plasticity solution for gravitational and earthquake-induced earth pressures on retaining walls.…”

Section: Mylonakis (2007)mentioning

confidence: 99%

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Seismic Earth Pressures on Retaining Structures and Basement Walls in Cohesionless Soils

Mikola

Candia

Sitar

2016

J. Geotech. Geoenviron. Eng.

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Observations of the performance of basement walls and retaining structures in recent earthquakes show that failures of basement or deep excavation walls in earthquakes are rare even if the structures were not designed for the actual intensity of the earthquake loading. Failures of retaining structures are most commonly confined to waterfront structures retaining saturated backfill with liquefaction being the critical factor in the failures. Failures of other types of retaining structures are relatively rare and usually involve a more complex set of conditions, such as sloping ground either above or below the retaining structure, or both. While some failures have been observed, there is no evidence of a systemic problem with traditional static retaining wall design even under quite severe loading conditions. No significant damage or failures of retaining structures occurred in the recent earthquakes such as Wenchuan earthquake in China (2008) and, or the large subduction zone earthquakes in Chile (2010) and Japan (2011). Therefore, this experimental and analytical study was undertaken to develop a better understanding of the distribution and magnitude of seismic earth pressures on cantilever retaining structures.The experimental component of the study consists of two sets of dynamic centrifuge model experiments. In the first experiment two model structures representing basement type setting were used, while in the second test a U-shaped channel with cantilever sides and a simple cantilever wall were studied. All of these structures were chosen to be representative of typical designs. Dry medium-dense sand with relative density on the order of from 75% to 80% was used as backfill. Results obtained from the centrifuge experiments were subsequently used to develop and calibrate a two-dimensional, nonlinear, finite difference model built on the FLAC platform.The centrifuge data consistently shows that for the height of structures considered herein, i.e. in the range of 20-30 ft, the maximum dynamic earth pressure increases with depth and can be reasonably approximated by a triangular distribution This suggests that the point of application of the resultant force of the dynamic earth pressure increment is approximately 1/3H 2 above the base of the wall as opposed to 0.5-0.6 H recommended by most current design procedures. In general, the magnitude of the observed seismic earth pressures depends on the magnitude and intensity of shaking, the density of the backfill soil, and the type of the retaining structures. The computed values of seismic earth pressure coefficient ( K ae ) back calculated from the centrifuge data at the time of maximum dynamic wall moment suggest that for free standing cantilever retaining structures seismic earth pressures can be neglected at accelerations below 0.4 g. While similar conclusions and recommendations were made by , their approach assumed that a wall designed to a reasonable static factor of safety should be able to resist seismic loads up 0.3 g. In the present study, experimental da...

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Section: Discussionmentioning

confidence: 65%

Section: Dynamic Lateral Earth Pressures Observed In Centrifuge Expermentioning

confidence: 66%

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Seismic Earth Pressures on Retaining Structures and Basement Walls in Cohesionless Soils

Mikola

Candia

Sitar

2016

J. Geotech. Geoenviron. Eng.

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“…While various modifications of this method have been introduced since, e.g. Seed and Whitman [5] and Mylonakis et al [6], the principal problem for a designer is that at high accelerations, > 0.5g, these methods predict very large dynamic forces, which appear unrealistic in view of actual experience in recent earthquakes. The problem of predicting high seismic loads becomes even more pronounced in the design of "non-yielding walls", defined as structures based on rock or very stiff soil that will not deflect more than 0.002H [2], which is based on a solution by Wood [7].…”

Section: Introductionmentioning

confidence: 99%

On seismic response of stiff and flexible retaining structures

Wagner¹,

Sitar

2016

Soil Dynamics and Earthquake Engineering

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A B S T R A C TThis paper presents an overview of the results of experimental and analytical studies of the seismic response of stiff and flexible retaining structures. These studies were motivated by very large dynamic forces in areas of high seismicity predicted by current seismic design methodologies based on the work of Okabe [3] and Mononobe and Matsuo [4]. However, there is no evidence of systematic failures of retaining structures in major earthquakes even when the ground accelerations clearly exceeded the design assumptions. The experimental program consisted of a series of geotechnical centrifuge model studies with different types of structures with cohesionless and cohesive backfill. Overall, the results of these studies show that the Mononobe-Okabe (M-O) method of analysis provides a reasonable upper bound for the response of stiff retaining structures and that flexible retaining structures experience loads significantly smaller than those predicted by this method. Moreover, for deep embedded structures the dynamic forces do not continue to increase with depth and gradually become a small fraction of the overall load on the walls.

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“…Well after the seminal works by Okabe [27] and Mononobe and Matsuo [25], several studies have tackled the problem of computing active dynamic pressures with a theoretical [20,24,29,17], experimental [2] and numerical approach [10,8].…”

Section: Introductionmentioning

confidence: 99%

A two-rigid block model for sliding gravity retaining walls

Conti

Viggiani

Cavallo

2013

Soil Dynamics and Earthquake Engineering

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a b s t r a c tThis paper presents a new two-rigid block model for sliding gravity retaining walls. Some conceptual limitations of a direct application of Newmark's sliding block method to the case of retaining walls are discussed with reference to a simple scheme of two interacting rigid blocks on an inclined plane. In particular, it is shown that both the internal force between the blocks and their absolute acceleration are not constant during sliding, and must be computed by direct consideration of the dynamic equilibrium and the kinematic constraints for the whole system. The same concepts are extended to the analysis of the active soil wedge-wall system, leading to an extremely simple procedure for computing the relative displacements of the wall when subjected to base accelerations exceeding the critical value. A comparison with the results of numerical analyses demonstrates that the proposed method is capable of describing fully the kinematics of the soil wedge-wall system under dynamic loading. On the contrary, direct application of Newmark's method may lead to inaccurate predictions of the final displacements, in excess or in defect depending on a coefficient which emerges from direct consideration of the dynamic equilibrium of the whole system. This coefficient can be viewed as a corrective factor for the horizontal relative acceleration of the wall, related to the mechanical and geometrical properties of the soil-wall system.

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An alternative to the Mononobe–Okabe equations for seismic earth pressures

Cited by 157 publications

References 14 publications

Seismic Earth Pressures on Retaining Structures and Basement Walls in Cohesionless Soils

Seismic Earth Pressures on Retaining Structures and Basement Walls in Cohesionless Soils

On seismic response of stiff and flexible retaining structures

A two-rigid block model for sliding gravity retaining walls

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