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1.
Motivated by the observed (successful and unsuccessful) performance of numerous structures on top of, or immediately next
to a normal fault that ruptured during the Kocaeli 1999 earthquake, this paper: (i) develops a two-step finite element methodology
to study the propagation of a fault rupture through soil and its interplay with the foundation–structure system, denoted hereafter
“Fault Rupture–Soil– Foundation–Structure Interaction” (FR–SFSI), (ii) provides validation of the developed methodology through
successful Class “A” predictions of centrifuge model tests, and (iii) applies the centrifuge-validated methodology to study
one-by-one the Kocaeli case histories of the first paper (Part I). It is shown that the presence of a structure on top of
an outcropping fault may have a significant influence on the rupture path: with heavy structures founded on continuous and
rigid foundations, the fault rupture diverts substantially and may avoid rupturing underneath the structure. The latter undergoes
rigid body rotation, with its foundation sometimes loosing contact with the bearing soil, but in most cases retaining its
structural integrity. In stark contrast, buildings on isolated footings and, perhaps surprisingly, piles exert a smaller diversion
of the rupture which is thus likely to outcrop between the footings or pile caps; the latter may thus undergo devastating
differential displacements. It is shown that structures in the vicinity of faults can be designed to survive significant dislocations.
The “secret” of successful performance lies on the continuity, stiffness, and rigidity of the foundation. 相似文献
2.
Construction of buildings in the proximity to seismically active faults is restricted by clause 4.1.2 of Eurocode 8 Part 5.
However, there is no clear definition of the safe distance to fault, and the uncertainty related to the location of main and
secondary traces of rupture for a future event can prevent the reduction of fault-breakage related risks to acceptable levels.
The diversion of the surface trace of rupture by massive structures seated on thick soil deposits can be beneficial for the
risk reduction. The scope of this study is first to revise previous theoretical approaches for providing simple engineering
criteria for the diversion of the surface breakage of fault rupture for shallow foundations and, secondly, to extend them
to treat the case of drained soils subjected to normal or reverse fault. The applicability of these criteria, which essentially
provide minimum values for the weight of structure depending on the thickness of the surface soil deposit, is discussed through
comparisons with the experimental results. 相似文献
3.
E. Faccioli I. Anastasopoulos G. Gazetas A. Callerio R. Paolucci 《Bulletin of Earthquake Engineering》2008,6(4):557-583
The 1999 earthquakes in Turkey and Taiwan, offering a variety of case histories with structures subjected to large tectonic
displacements, have refueled the interest of the earthquake engineering community on the subject. While several structures
were severely damaged or even collapsed, there were numerous examples of satisfactory performance. Even more astonishingly,
in specific cases the surface fault rupture was effectively diverted due to the presence of a structure. For the purpose of
developing deeper insights into the main mechanisms controlling this fascinating interplay, this article documents selected
field case histories of fault rupture–foundation interaction from (a) the Mw 7.4 Kocaeli (August 17) 1999 earthquake in Turkey, (b) the Mw 7.1 Düzce-Bolu (November 12) 1999 earthquake in Turkey, (c) the Mw 7.6 Chi–Chi (September 21) 1999 earthquake in Taiwan, and (d) surface faulting in Mount Etna. A subset of the case histories
presented herein is analysed numerically, using the methods developed in the companion paper. It is shown that relatively
“heavy” or stiff structures supported by continuous and rigid foundations may divert the fault rupture. Such structures are
subjected to rigid body rotation, without substantial structural distress. In contrast, structures on structurally–resilient
foundation systems or on isolated supports are prone to substantial damage. 相似文献
4.
The dynamic response and seismic performance of bridges may be appreciably affected by numerous contributing factors, with
soil–structure interaction being the dominant exogenous influence. The most familiar form is the so-called soil–pile interaction,
but embankment–abutment interaction is also documented through field observations and analytical investigations, particularly
evident in integral R.C. bridges. Recent studies have shown that this form of interaction may significantly alter the bridge
response and should be taken into account during design and assessment, especially in the case of typical highway overcrossings
that have abutments supported on earth embankments. In light of this emerging problem and in order to facilitate quantitative
estimates of the interaction effects, the question of appropriate modeling and seismic assessment of R.C. integral bridges
is the main object of the present paper. Based on already established procedures to account for soil–structure interaction,
a new approach is proposed to model the contribution of the embankment, the bent and the abutments to the overall bridge response.
Furthermore, the capacity curve of the entire bridge system is evaluated through the implementation of Incremental Dynamic
Analysis (IDA), therefore allowing for seismic assessment of the complex superstructure–foundation system with well established
displacement based procedures. Using as a benchmark case two typical instrumented U.S. highway bridges located in California,
the proposed method is implemented and provided results from this analysis are correlated successfully with available field
data. Results obtained from the analysis indicate excessive displacement demands for the entire bridge–embankment system owing
to the embankment contribution and the soil degradation under increasing shear strains. Furthermore, seismic performance is
strongly related to the central bent deformation capacity, with soil–pile interaction effects being of critical importance. 相似文献
5.
G. Gudehus R. O. Cudmani A. B. Libreros-Bertini M. M. Bühler 《Soil Dynamics and Earthquake Engineering》2004,24(4):319-342
The concept of in-plane and anti-plane shaking is introduced with a rigid block on a plane surface with Coulomb friction. Using a hypoplastic constitutive relation to model the mechanical behaviour of the soil, numerical solutions for a rigid block on a thin dry or saturated soil layer are obtained. The coupled nature of dynamic problems involving granular materials is shown, i.e. the motion of the block changes the soil state—skeleton stresses and density—which in turn affects the block motion. Motions of the block as well as soil response can be more realistically calculated by the new model. The same constitutive equation is applied to the numerical simulation of the propagation of plane waves in homogeneous and layered level soil deposits induced by a wave coming from below. Experiments with a novel laminar shake box as well as real seismic records from well-documented sites during strong earthquakes are used to verify the adequacy of the hypoplasticity-based numerical model for the prediction of soil response during strong earthquakes. The response of a homogeneous earth dam subjected to in-plane and anti-plane shaking is investigated numerically. In-plane and anti-plane shaking is shown to cause nearly the same spreading of a sand dam under drained conditions, whereas under undrained conditions anti-plane shaking causes stronger spreading of the dam. The dynamic behaviour of a breakwater founded on rockfill and soft clay during the 1995 Kobe earthquake is back-calculated to show the good performance of the proposed numerical model also with a structure. Section 9 deals with buildings on mattresses of densified cohesionless soils or fine-grained soils with granular columns, slopes with ‘hidden’ dams and structures on piles traversing clayey slopes to show the suitability of hypoplasticity-based models for the earthquake-resistant design and safety assessment of geotechnical systems. 相似文献