Beam-on-Nonlinear-Winkler-Foundation Modeling of Shallow, Rocking-Dominated Footings

2009 ◽  
Vol 25 (2) ◽  
pp. 277-300 ◽  
Author(s):  
Chad W. Harden ◽  
Tara C. Hutchinson
Keyword(s):  
Earthquake Engineering ◽  
Energy Content ◽  
Nonlinear Behavior ◽  
Seismic Energy ◽  
Shallow Foundation ◽  
Winkler Foundation ◽  
Soil Foundation ◽  
Performance Based Earthquake Engineering ◽  
Foundation Structure ◽  
Selection Of

The nonlinear behavior of shallow foundations under large amplitude earthquake-induced loading can result in dissipation of seismic energy through the mechanism of soil yielding beneath the foundation. In addition, foundation uplifting may shift the period of the soil-foundation-structure system away from the damaging energy content of most earthquakes. However, this yielding and uplifting may lead to excessive transient and permanent deformations (settlement, rocking, and sliding). Therefore, modeling procedures that account for foundation nonlinearity and uplift are needed before these benefits can be realized in performance based earthquake engineering (PBEE) practice. This paper adopts a beam-on-nonlinear-Winkler-foundation (BNWF) simulation methodology for modeling shallow foundation-structure systems, where seismically-induced rocking plays a predominant role in their response. Numerical results demonstrate that reasonable comparison between the nonlinear Winkler-based approach, and experimental response in terms of moment-rotation, settlement-rotation, and shear-sliding displacement can be obtained, given an appropriate selection of model and soil properties.

Comparison between standards for seismic design of liquid storage tanks with respect to soil-foundation-structure interaction and uplift

2012 ◽  
Vol 45 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Miguel Ormeño ◽  
Tam Larkin ◽  
Nawawi Chouw
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Earthquake Engineering ◽  
Storage Tanks ◽  
Base Shear ◽  
Structure Interaction ◽  
Liquid Storage ◽  
Field Evidence ◽  
Soil Foundation ◽  
Foundation Structure

Field evidence has established that strong earthquakes can cause severe damage or even collapse of liquid storage tanks. Many tanks worldwide are built near the coast on soft soils of marginal quality. Because of the difference in stiffness between the tank (rigid), foundation (rigid) and the soil (flexible), soil-foundation-structure interaction (SFSI) has an important effect on the seismic response, often causing an elongation of the period of the impulsive mode. This elongation is likely to produce a significant change in the seismic response of the tank and will affect the loading on the structure. An issue not well understood, in the case of unanchored tanks, is uplift of the tank base that usually occurs under anything more than moderate dynamic loading. This paper presents a comparison of the loads obtained using “Appendix E of API STANDARD 650” of the American Petroleum Institute and the “Seismic Design of Storage Tanks” produced by the New Zealand Society for Earthquake Engineering. The seismic response assessed using both codes is presented for a range of tanks incorporating a range of the most relevant parameters in design. The results obtained from the analyses showed that both standards provide similar base shear and overturning moment; however, the results given for the anchorage requirement and uplift are different.

Behavior of the Leaning Tower of Pisa: Insights on Seismic Input and Soil-Structure Interaction

2016 ◽  
Vol 847 ◽  
pp. 454-462 ◽  
Author(s):  
Raffaello Bartelletti ◽  
Gabriele Fiorentino ◽  
Giuseppe Lanzo ◽  
Davide Lavorato ◽  
Giuseppe Carlo Marano ◽  
...  
Keyword(s):  
Earthquake Engineering ◽  
Soil Structure ◽  
Dynamic Monitoring ◽  
Element Analysis ◽  
Structure Interaction ◽  
Scenario Earthquakes ◽  
The Finite Element Analysis ◽  
Soil Foundation ◽  
Foundation Structure ◽  
Made In

The most recent studies about the seismic behavior of the leaning Tower of Pisa that consider the soil-foundation-structure interaction date back to twenty years ago. From 1999 to 2001, the foundation of the monument was consolidated by means of under-excavation and the "Catino" at the basement was rigidly connected to the foundation. Meanwhile, significant progresses have been made in the field of earthquake engineering. Therefore, the need exists to assess the dynamic behavior of the Tower in light of the novelties occurred in the past decades. In the present study, the mechanical characteristics of the foundation have been calibrated comparing the outcomes of the experimental dynamic monitoring with the results of the finite element analysis performed on a simple but effective model. The scenario earthquakes for return periods equal to 130 years and 500 years are also presented.

The pattern of distribution of vertical stress of swelling of soil under foundations and underground structures

2016 ◽  
Vol 4 (3) ◽  
pp. 60-67
Author(s):  
Раис Абжалимов ◽  
Rais Abzhalimov
Keyword(s):  
Strain State ◽  
Vertical Stress ◽  
Strip Foundation ◽  
Underground Structures ◽  
Foundation Soil ◽  
Swelling Soils ◽  
Swelling Soil ◽  
Soil Foundation ◽  
Foundation Structure ◽  
Selection Of

Examines the pattern of distribution of vertical stress of swelling of soil under foundations and underground structures, stress-strain state (VAT) system, "swelling soil-Foundation - structure" for the strip Foundation and VAT for a square Foundation when uneven wetting of the Foundation soil. Provides recommendations for selection of type of foundations on swelling soils.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

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