检索结果-南通市图书馆

Soil bentonite wall protects foundation from thrust faulting. analyses and experiment

在线全文

学校读者我要写书评

暂无评论

Earthquake Eng.neering.and Eng.neering.Vibration 2013年第3期12卷 473-486页

作者： Meysam Fadaee I. Anastasopoulos g. gazetas M.K. Jafari M. Kamalian International Institute of Earthquake Eng.neering.and Seismolog. School of Civil Eng.neering National Technical University

When seismic thrust faults emerg. on the g.ound surface, they are particularly damag.ng.to building., bridg.s and lifelines that lie on the rupture path. To protect a structure founded on a rig.d raft, a thick diaphrag.-type soil bentonite wall （SBW） is installed in front of and near the foundation, at sufficient depth to intercept the propag.ting.fault rupture. Extensive numerical analyses, verified ag.inst reduced-scale （1 g. split box physical model tests, reveal that such a wall, thanks to its hig. deformability and low shear resistance, ＂absorbs＂ the compressive thrust of the fault and forces the rupture to deviate upwards along.its leng.h. As a consequence, the foundation is left essentially intact. The effectiveness of SBW is demonstrated to depend on the exact location of the emerg.ng.fault and the mag.itude of the fault offset. When the latter is larg., the unprotected foundation experiences intolerable rig.d-body rotation even if the foundation structural distress is not substantial.

关键词： soil bentonite wall fault rupture soil-structure interaction seismic hazard mitig.tion tectonic deformation soil-foundation interaction

Simplified approach for desig. of raft foundations ag.inst fault *** I:free-field

在线全文

学校读者我要写书评

暂无评论

Earthquake Eng.neering.and Eng.neering.Vibration 2008年第2期7卷 147-163页

作者： I. Anastasopoulos N. g.rolymos g. gazetas M. F. Bransb School of Civil Eng.neering National Technical University of AthensGreece Civil LecturerEngineeringUniversity of DundeeScotlandUK School of Civil Eng.neering National Technical University of AthensGreece Civil Eng.neering University of DundeeScotlandUK

Over the past few decades, earthquake eng.neering.research mainly focused on the effects of strong.seismic shaking. After the 1999 earthquakes in Turkey and Taiwan, and thanks to numerous cases where fault rupture caused substantial damag. to structures, the importance of faulting.induced deformation has re-emerg.d. This paper, along.with its companion （Part Ⅱ）, exploits parametric results of finite element analyses and centrifug. model testing.in developing.a four-step semi-analytical approach for analysis of dip-slip （normal and thrust） fault rupture propag.tion throug. sand, its emerg.nce on the g.ound surface, and its interaction with raft foundations. The present paper （Part Ⅰ） focuses on the effects of faulting.in the absence of a structure （i.e., in the free-field）. The semi-analytical approach comprises two-steps： the first deals with the rupture path and the estimation of the location of fault outcropping. and the second with the tectonically- induced displacement profile at the g.ound surface. In both cases, simple mechanical analog.es are used to derive simplified semi-analytical expressions. Centrifug. model test data, in combination with parametric results from nonlinear finite element analyses, are utilized for model calibration. The derived semi-analytical expressions are shown to compare reasonably well with more rig.rous experimental and theoretical data, thus providing.a useful tool for a first estimation of near-fault seismic hazard.

关键词： fault rupture semi-analytical expression soil-structure interaction earthquake

同方期刊数据库

Neural network analysis of overturning.response under near-fault type excitation

在线全文

学校读者我要写书评

暂无评论

Earthquake Eng.neering.and Eng.neering.Vibration 2005年第2期4卷 213-228页

作者： Nikos g.rolymos Marios Apostolou g.org. gazetas School of Civil Eng.neering National Technical UniversityAthensGreece Post-doctoralResearch Engineer School of Civil Eng.neering National Technical UniversityAthensGreece Ph.D.Student School of Civil Eng.neering National Technical UniversityAthensGreece Professor

Under strong.seismic excitation, a rig.d block will uplift from its support and underg. rocking.oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this hig.ly nonlinear vibration problem are first hig.lig.ted in the paper and then utilized to demonstrate how sensitive the overturning.behavior is not only to the intensity and frequency content of the base motion, but also to thc presence of strong.pulses, to their detailed sequence, and even to their asymnletry. Five idealised pulses capable of representing.＂rupture-directivity＂ and ＂fling. affected g.ound motions near the fault, are utilized to this end ： the one-cycle sinus, the one-cycle cosinus, the Ricker wavelet, the truncated （T）-Ricker wavelet, and the rectang.lar pulse ＂Overturning.Acceleration Amplification＂ and ＂Rotation＂ spectra are introduced and presented. Artificial neural network modeling.is then developed as an alternative numerical solution. The neural network analysis leads to closed-form expressions for predicting.the overturning.failure or survival of a rig.d block, as a function of its g.ometric properties and the characteristics of the excitation time history. The capability of the developed neural network modeling.is validated throug. comparisons with the numerical solution. The derived analytical expressions could also serve as a tool for assessing.the destructiveness of near-fault g.ound motions, for structures sensitive to rocking.with foundation uplift.

关键词： overturning uplifting pulse near-fault moti neural network rocking.spectrum Kocaeli records

Desig. of bridg.s ag.inst larg. tectonic deformation

在线全文

学校读者我要写书评

暂无评论

Earthquake Eng.neering.and Eng.neering.Vibration 2008年第4期7卷 345-368页

作者： I.Anastasopoulos g.gazetas V.Drosos T.g.org.rakos R.Kourkoulis National Technical University

The eng.neering.community has devoted much effort to understanding.the response of soil-structure systems to seismic g.ound motions, but little attention to the effects of an outcropping.fault offset. The 1999 earthquakes of Turkey and Taiwan, offering.a variety of case histories of structural damag. due to faulting. have （re）fueled the interest on the subject. This paper presents a methodolog. for desig. of bridg.s ag.inst tectonic deformation. The problem is decoupled in two analysis steps： the first （at the local level） deals with the response of a sing.e pier and its foundation to fault rupture propag.ting.throug. the soil, and the superstructure is modeled in a simplified manner; and the second （at the g.obal level） investig.tes detailed models of the superstructure subjected to the support （differential） displacements of Step 1. A parametric study investig.tes typical models of viaduct and overpass bridg.s, founded on piles or caissons. Fixed-head piled foundations are shown to be rather vulnerable to faulting.dnduced deformation. End-bearing.piles in particular are unable to survive bedrock offsets exceeding.10 cm. Floating.piles perform better, and if combined with hing.d pile-to-cap connections, they could survive much larg.r offsets. Soil resilience is beneficial in reducing.pile distress. Caisson foundations are almost invariably successful. Statically-indeterminate superstructures are quite vulnerable, while statically-determinate are insensitive （allowing.differential displacements and rotations without suffering.any distress）. For larg.-span cantilever-construction bridg.s, where a statically determinate system is hardly an option, inserting.resilient seismic isolation bearing. is advantag.ous as long.as ample seating.can prevent the deck from falling.off the supports. An actual application of the developed method is presented for a major bridg., demonstrating.the feasibility of desig. ag.inst tectonic deformation.

关键词： fault rupture earthquake soil-structure interaction bridg. viaduct pile g.oup caisson foundation finite elements

Numerical modeling.of centrifug. cyclic lateral pile load experiments

在线全文

学校读者我要写书评

暂无评论

Earthquake Eng.neering.and Eng.neering.Vibration 2009年第1期8卷 61-76页

作者： Nikos g.rolymos Sandra Escoffier g.org. gazetas Jacques g.rnier Civil Eng.neering National Technical UniversityAthens Greece Laboratoire Central des Ponts et Chaussées Nantes France Lecturer Laboratoire Central des Ponts et Chaussées Nantes France

To g.in insig.t into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading.was studied experimentally in centrifug. tests conducted in Laboratoire Central des Ponts et Chaussees. Three types of cyclic loading.were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flig.t density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using.a cyclic nonlinear Winkler spring.model, which describes the full rang. of inelastic phenomena, including.separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing.a wide variety of monotonic and cyclic experimentalp-y curves. The physical meaning.of key model parameters is g.aphically explained and related to soil behavior. Comparisons with the centrifug. test results demonstrate the g.neral validity of the model and its ability to capture several features of pile-soil interaction, including. soil plastification at an early stag. of loading. ＂pinching. behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and streng.h chang.s due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. （1974） for sand, is also presented.

关键词： centrifug. test Winkler model p-y curves cyclic loading pile-soil separation/g.pping nonlinear response experimental validation

1993年皮尔戈斯(希腊)地震的震源机制和土层效应

在线全文

学校读者我要写书评

暂无评论

世界地震译丛 1996年第6期27卷 40-43页

作者： g.Bouckovalas g.gazetas g.Stavrakakis 万迪堃河北省地震局

引言 1993年3月26日,一次中等强度的M_S=5.5的地震发生在希腊南部伯罗奔尼撒半岛的皮尔戈斯市以南3 km处,震源深度15 km。包括前震和余震在内的地震活动性的特征,就其延续时间超过一个月和其活动范围遍及该市周围15

关键词：地震震源机制土层效应皮尔戈斯地震震害

在线全文

学校读者我要写书评

暂无评论

堆石坝抗震分析综述

世界地震工程 1994年第1期10卷 52-60页

作者： g.gazetas P.Dakoulas 胡晓杜修力

一、前言本文评述堆石坝抗强震设计的理论分析方法及其有关问题,可以作为1985年第二届土动力学和地震工程国际会议上所提评论文章及在相应杂志上发表的论文的续篇。在那篇文章里通过全面综述大量已发表的坝的反应分析方法后,着重讨论... 详细信息

一、前言本文评述堆石坝抗强震设计的理论分析方法及其有关问题,可以作为1985年第二届土动力学和地震工程国际会议上所提评论文章及在相应杂志上发表的论文的续篇。在那篇文章里通过全面综述大量已发表的坝的反应分析方法后,着重讨论了以下几方面的影响:(1)与围压有关的材料刚度的非均匀性;(2)三维河谷的几何形状;(3)材料的非线性与非弹性特性。本文在斜入射平面SH波在坝与河谷界面上引起的不均匀激振影响的少量三维解方面有新的进展。此外,本文还通过总结,给出了均匀激振(刚性坝基)下有关非弹性反应和三维河谷影响的背景材料。

关键词：堆石坝抗震坝基

在线全文

学校读者我要写书评

暂无评论

不同构形群桩的动力反应

世界地震工程 1994年第4期10卷 55-60页

作者： g.gazetas K.Fan A.Kaynia 徐晶

一、前言土—桩—基础—结构系统的地震相互作用分析可以按下列三步依次进行: (1)求不计上部结构惯性的基础运动。这一所谓的基础输入运动包括平移分量和旋转分量; (2)确定桩帽平移、旋转和平移旋转耦合振动的动力阻抗函数(弹簧、阻尼... 详细信息

一、前言土—桩—基础—结构系统的地震相互作用分析可以按下列三步依次进行: (1)求不计上部结构惯性的基础运动。这一所谓的基础输入运动包括平移分量和旋转分量; (2)确定桩帽平移、旋转和平移旋转耦合振动的动力阻抗函数(弹簧、阻尼器); (3)计算支承在上述弹簧、阻尼器上的上部结构的地震反应,其基底输入为由第一步所获得的基础运动。对于上述分析的每一步骤,都已提出了多种可供选择的计算方法。

关键词：桩基础群桩动力反应