Model of Soil-structure Interaction of Objects Resting on Finite Depth Soil Layers for Seismic Design

Pap, Zsuzsa B.; Kollár, László P.

doi:10.3311/ppci.14459

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…The wavelength L is approximated by the following reasoning. For shallow layers, a quarter-wave is assumed in the soil [23], Fig. 4(a).…”

Section: Assumptions and Basic Hypothesismentioning

confidence: 99%

Role of Nonlinearity in the Soil in Earthquake-Resistant Design of Structures

Shayah,

Kollár

2023

Period. Polytech. Civil Eng.

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The nonlinearity of the soil may considerably affect the response of structures subjected to seismic events. This paper aims to show under which circumstances geometry, soil, and earthquake-type; the nonlinearity is important. A simple model based on a 1D shear column was developed to calculate the maximum shear strain (γ) in the soil subjected to earthquake excitation. It was found that γ is a function of peak ground acceleration PGA and the maximum horizontal ground displacement (∆). EC8 provides an expression for calculating ∆ that is independent of the soil thickness. It was found that this expression is conservative for shallow layers and underestimates γ for thick ones, as a result, improvements have been suggested. By performing several time history analyses, simple formulas are developed which enable the designer to assess when nonlinearity must be taken into account. Four curves based on soil thickness and peak ground acceleration have been introduced for different soil types (A, B, C, and D) using a limit value of γ = 10–4. These curves show that depending on the soil depth, the threshold acceleration of nonlinear soil behavior is around 0.48, 0.36, 0.29, and 0.10 m/s2 for soil types A, B, C, and D, respectively. Obviously, nonlinear analysis must be performed for shallow soil layers under moderate seismicity.

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“…The wavelength L is approximated by the following reasoning. For shallow layers, a quarter-wave is assumed in the soil [23], Fig. 4(a).…”

Section: Assumptions and Basic Hypothesismentioning

confidence: 99%

Role of Nonlinearity in the Soil in Earthquake-Resistant Design of Structures

Shayah,

Kollár

2023

Period. Polytech. Civil Eng.

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“…When the undamped (ξ=0), infinitely long constrained beam or bar is loaded by a harmonic edge load at x=0; for ω< ωc the steady-state solution shows no energy dissipation, it behaves like a SDOF system. However, when ω> ωc there is energy dissipation (due to the so called "radiation damping") and the displacement propagates far from the edge [15].…”

Section: Analytical and Numerical Solution Of Long Platesmentioning

confidence: 99%

Human Induced Vibration of Long Rectangular Steel and Composite Floors

Pap¹,

Kollár²

2021

ce papers

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Recently several light‐weight, long span floors are built (e.g. steel‐framed structural systems), where the design is governed by vibration control. In these cases the acceleration due to human‐ or machine‐induced vibration can be very high, which may cause human discomfort. Long rectangular plates subjected to concentrated loads are often investigated by a replacement beam with a so called “effective width”, and the amplification factor is calculated according to a SDOF system, which in the case of resonance is equal to 1/2ξ, where ξ is the damping ratio. Since damping in lightweight, steel‐framed structural systems is very low (1–3%), dynamic amplification (calculated according to an SDOF system) can be rather high. However, the steady‐state dynamic response of beams and long plates subjected to periodic loads are significantly different. The steel‐framed floors are mechanically long even in that case when the ratio of the sides of the floor is around one due to the high orthotropy. For long plates, the response and the amplification factor are substantially different from those of beams. Hence, design based on effective width may lead to 2‐4 times higher acceleration than the real values. As an example the roof of a gymnasium under construction is examined, where different sport activities (walking, running, aerobic) will take place. The natural frequency of the floor supported by steel joists is small, close to the frequency of walking, therefore a detailed vibration analysis was performed.

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“…Therefore, small-scale tests, numerical evaluations, and real-scale tests have shown that rocking foundations' application can be considered an efficient approach to reducing damage to structures. Pap and Kollár [29] conducted a study to model of soil-structure interaction of objects resting on finite depth soil layer using a simplified model, and their finding showed that in modeling the soil-foundation interaction by finite element method, the effects of soil should be taken into account by their introduced model.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Behavior of Bridge Piers Considering Rocking Isolation Constructed on Non-plastic Silts and Sands Using 1g Shaking Table Tests

Irani

Hajialilue-Bonab

Sarand

et al. 2023

Period. Polytech. Civil Eng.

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Occurred damages on the bridge piers during earthquakes lead to significant financial losses worldwide every year and can cause social problems by disrupting traffic flow and transportation services. Rocking isolation of foundations is one of the damage reduction approaches to avoid structural damage on piers by transferring plastic hinges from piers to underlying soil media. The behavior of rocking foundations on non-plastic silts has not been investigated well until now in the literature. In this research, the characteristic seismic behavior of a bridge pier considering rocking isolation is evaluated using small-scale physical modeling tests. To this aim, eight shaking table tests (with sinusoidal excitations) are conducted where both sandy and silty materials are employed as the soil media. In addition to the effects of the underlying soil, the effects of the critical contact area ratio of the foundation and frequency of input motions are evaluated. Achieved results indicate that the considered bridge pier shows the same behavior trend for underlying silty soil and sandy one. However, because of the frequency-dependent behavior of non-plastic silty soil, the pier attracts lower accelerations and higher moments. Therefore, the achieved results show that the proposed design approaches of rocking foundations that are mostly extracted based on experimental studies on sands (or rarely on clay) can lead to non-conservative designs in silty soils.

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Model of Soil-structure Interaction of Objects Resting on Finite Depth Soil Layers for Seismic Design

Cited by 3 publications

References 13 publications

Role of Nonlinearity in the Soil in Earthquake-Resistant Design of Structures

Role of Nonlinearity in the Soil in Earthquake-Resistant Design of Structures

Human Induced Vibration of Long Rectangular Steel and Composite Floors

Investigation on the Behavior of Bridge Piers Considering Rocking Isolation Constructed on Non-plastic Silts and Sands Using 1g Shaking Table Tests

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