SHORT COMMUNICATION Influence of the soil–structure interaction on the fundamental period of buildings
Author: Louay Khalil , Marwan Sadek , , and Isam Shahrour | Size: 0.16 MB | Format:PDF | Quality:Unspecified | Publisher: EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS Earthquake Engng Struct. Dyn. 2007; 36:2445–2453 Published online 2 August 2007 in Wiley InterScience. DOI: 10.1002/eqe.738 | Year: 2007 | pages: 9
This paper includes an investigation of the influence of the soil–structure interaction (SSI) on the fundamental period of buildings. The behaviour of both the soil and the structure is assumed to be elastic. The soil-foundation system is modelled using translational and rotational discrete springs. Analysis is first conducted for one-storey buildings. It shows that the influence of the SSI on the fundamental frequency of building depends on the soil–structure relative rigidity Kss. Analysis is then extended for multi-storey buildings. It allows the generalization of the soil–structure relative rigidity Ks to such complex structures. Charts are proposed for taking into account the influence of the SSI in the calculation of the fundamental frequency of a wide range of buildings.
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DYNAMIC SOIL BEHAVIOR and DYNAMIC SOIL-STRUCTURE INTERACTION
Author: George Gazetas Professor of Civil Engineering National Technical University of Athens | Size: 6.2 MB | Format:PDF | Quality:Unspecified | Publisher: SERINA 1997, THESSALONIKI | Year: 2001 | pages: 73
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RECOMMENDATIONS FOR SOIL STRUCTURE INTERACTION (SSI) INSTRUMENTATION
Author: M. Çelebi and C.B. Crouse | Size: 0.33 MB | Format:PDF | Quality:Unspecified | Publisher: COSMOS (Consortium of Organizations for Strong-Motion Observation Systems) Workshop on Structural Instrumentation Emeryville, Ca. November 14-15, 2001 | Year: 2001 | pages: 18
The objectives of this paper are to:
• introduce the recommendations of a workshop held in 1992 that aimed to define the
background information in establishing a special purpose array in a seismically
active region of the United States to study specifically the effect of SSI and define
the parameters and details of a SSI experiment,
• summarize two recent workshops that in general discussed the SSI subject,
• describe the current state of implementation in the US and Japan.
The objectives of the 1992 workshop were: (a) to bring together a panel of experts to reach a
consensus on the benefits and feasibility of instrumenting a building in a seismically active region of
the United States to study specifically the effect of SSI, and (b) to discuss and determine the details
of such a SSI experiment.
1
Research Civil Engineer, USGS (MS977), 345 Middlefield Rd., Menlo Park, Ca. 94025
2
Principal Engineer and Vice President, URS Corporation, Seattle, WA 98101-1616
Celebi_cosmos_ssi_pap 11/7/2001 12:27 PM
1
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Soil structure interaction analysis methods - State of art-Review
Author: Siddharth G. Shah , Solanki C.H. , Desai J.A. | Size: 0.36 MB | Format:PDF | Quality:Unspecified | Year: 2011 | pages: 29
Soil flexibility has to be considered in the analysis of massive structures to avoid failure
and ensure safe service. Post failure analysis of massive structures realized the
importance of SSI-soil structure interaction. In the literature as many as half dozen
methods are available but researches and designers are not clear about the history &
development in this field. Current paper attempts to review the stat of art about soil
structure interaction analysis methods. The review reveals that for simple analysis direct
methods-Global procedures are physible while for non linear analysis substructure
method is effective and simple to apply.
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SOIL STRUCTURE INTERACTION EFFECTS ON MULTISTOREY R/C STRUCTURES
Author: Muberra ESER AYDEMIR | Size: 2.9 MB | Format:PDF | Quality:Unspecified | Publisher: INTERNATIONAL JOURNAL OF ELECTRONICS; MECHANICAL and MECHATRONICS ENGINEERING Vol.2 Num.3 pp.(298-303) | pages: 6
his paper addresses the behavior of multistorey structures considering soil structure interaction under
earthquake excitation. For this purpose, sample 3, 6, 9 storey RC frames are designed based on Turkish Seismic
Design Code and analyzed in time domain with incremental dynamic analysis. Strength reduction factors are
investigated for generated sample plane frames for 64 different earthquake motions recorded on different site
conditions such as rock, stiff soil, soft soil and very soft soil. According to the analysis result, strength reduction
factors of sample buildings considering soil structure interaction are found to be almost always smaller than
design strength reduction factors given in current seismic design codes, which cause an unsafe design and nonconservative
design forces.
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Calculating long-term settlement in soft clays – with special focus on the Gothenburg region
Author: MATS OLSSON | Size: 5.3 MB | Format:PDF | Quality:Unspecified | Publisher: Department of Civil and Environmental Engineering Division of GeoEngineering CHALM ERS UNIVERSITY OF TECHNOLOGY Götebor g, Sweden 20 10 | Year: 2010 | pages: 132
Long-term settlement in clay constitutes an engineering challenge in road design
and construction in areas with deep deposits of soft clay. Soil improvement and
construction of building foundations or embankments can be quite complicated
and expensive in such areas. Construction costs need to be balanced against high
maintenance costs. In order to do this optimally, there is a need to predict longterm
settlement with a high degree of accuracy.
Two different test sites were chosen for back-calculation, a test embankment at
Nödinge and a groundwater lowering at Kaserntorget. There was also one
hypothetical test site.
In this thesis a short description is presented of the fundamental behaviour of soft
clays with regard to compressibility as well as a short explanation of the theory
for the three different models that has been used within this thesis – Embankco,
GS Settlement and the Soft Soil Creep model.
Soil parameter determination for long-term settlement analysis is discussed
together with some of the inherent complications. For the IL oedometer test the
study shows that if the time for the load stage of interest is not sufficiently long
the evaluated creep parameter could be misleading. Back-calculation of CRS
oedometer test, using the Soft Soil Creep model, is performed for this model and
a procedure is suggested.
The outcome of the analysis shows that all three models produce similar results
for the hypothetical case. For the two test sites in question, both GS Settlement
and the Soft Soil Creep model were capable of predicting the measured
settlement with acceptable accuracy. The Embankco program was only used for
the hypothetical case.
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Author: H.G. Poulos , J.C. Small and H. Chow | Size: 3.2 MB | Format:PDF | Quality:Unspecified | Publisher: Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol 42 No.2 June 2011 ISSN 0046-5828 | Year: 2011 | pages: 7
Piled raft foundations are increasingly being recognised as an economical and effective foundation system for tall buildings. This paper sets out some principles of design for such foundations, including design for the geotechnical ultimate limit state, the structural ultimate limit state and the serviceability limit state. The advantages of using a piled raft will then be described with respect to two cases: a
small pile group subjected to lateral loading, and then the design of the Incheon Tower in South Korea. Attention will be focussed on the improvement in the foundation performance due to the raft being in contact with, and embedded within, the soil.
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Author: Y.C. Uni & C.M. Chow | Size: 2 MB | Format:PDF | Quality:Unspecified | Publisher: Partners Sdn Bhd, Kuala Lumpur, Malaysia | Year: 2004 | pages: 20
Piled raft on soft ground is an economical foundation system where the bearing capacity of the raft is
taken into consideration in supporting the loads from superstructure. The friction piles in a piled raft
system are located strategically to enhance the bearing capacity of the raft and also to control settlement,
especially differential settlement and hence, these piles are commonly known as `settlement reducing
piles'. Therefore, piled raft is a technically competent foundation system and offers significant savings in
tenns of overall foundation cost as compared to conventional piled foundation. This is because
conventional piled foundation usually ignores the contribution of the raft and assumes the loads are
supported entirely by the piles. However, the use of piled raft foundation system requises careful design
and analysis as it involves complex pile-soif-structure interaction. In this paper, design issues on piled raft
foundation system wiil be discussed with particular reference to buildings on soft ground. However, the
approach presented in this paper is also applicable to more competent ground conditions. The design
approach is generally divided into two types, i.e. low-rise buildings (less than 3-storeys high) and
medium-rise buildings (3 to 5-storeys high). The piled raft foundation system lias been successfully
designed and constructed on soft ground, and case histories are presented.
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Long-term fatigue analysis of welded multi-planar tubular joints for a fixed jacket offshore wind turbine
designed for a North Sea site in a water depth of 70 m is performed. The dynamic response of the jacket
support structure due to wind and wave loads is calculated by using a decoupled procedure with good
accuracy (Gao et al., 2010). Hot-spot stresses at failure-critical locations of each reference brace for 4
different tubular joints (DK, DKT, X-type) are derived by summation of the single stress components from
axial, in-plane and out of plane action, the effects of planar and non-planar braces are also considered. Both
a 2-parameter Weibull function and generalized gamma function are used to fit the long-term statistical
distribution of hot-spot stress ranges by a combination of time domain simulation for representative
environmental conditions in operational conditions of the wind turbine. A joint probabilistic model of
mean wind speed Uw, significant wave height Hs and spectral peak period Tp in the northern North Sea
is used to obtain the occurrence frequencies of representative environmental conditions (Johannessen,
2002). In order to identify the contributions to fatigue damage from wind loads, wave loads and the
interaction effect of wind and wave loads, 3 different load cases are analyzed: wind loads only; wave loads
only; a combination of wind and wave loads. The representative environmental condition corresponding
to the maximum contribution to fatigue damage is identified. Characteristic fatigue damage of the selected
joints for different models is predicted and compared. The effect of brace thickness on the characteristic
fatigue damage of the selected joints is also analyzed by a sensitivity study. The conclusions obtained in
this paper can be used as the reference for the design of future fixed jacket offshore wind turbines in North
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USING PUSHOVER ANALYSIS METHOD IN SEISMIC ANALYSIS OF BRIDGES
Author: Hamed AlAyed1 and Chung C. Fu2 | Size: 0.325 MB | Format:PDF | Quality:Unspecified | pages: 12
Nonlinear Static (Pushover) Procedure (NSP) is specified in the guidelines for seismic
rehabilitation of buildings presented by FEMA-273 [1] as an analytical procedure that can be used in
systematic rehabilitation of structures. However, those guidelines were presented to apply the
Displacement Coefficient Method (DCM) only for buildings. This study is intended to evaluate the
applicability of NSP by implementing the DCM to bridges. For comparison purposes, the Nonlinear
Dynamic Procedure (NDP) (or nonlinear time-history analysis), which is considered to be the most
accurate and reliable method of nonlinear seismic analysis, is also performed.
A three-span bridge of 97.5 meters (320 ft) in total length was analyzed using both the NSP-DCM
and nonlinear time-history. Nine time-histories were implemented to perform the nonlinear time-history
analysis. Three load patterns were used to represent distribution of the inertia forces resulting from
earthquakes. Demand (target) displacement, base shear, and deformation of plastic hinges obtained from
the NSP are compared with the corresponding values resulting from the nonlinear time history analysis.
Analysis was performed using two levels of seismic load intensities (Design level and Maximum
Considered Earthquake (MCE) level). Performance of the bridge was evaluated against these two seismic
loads. Comparison shows that the NSP gives conservative results, compared to the nonlinear time history
analysis, in the Design Level while it gives more conservative results in the MCE Level.
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