scholarly journals A Comparison of Simplified Modelling Approaches for Performance Assessment of Piles Subjected to Lateral Spreading of Liquefied Ground

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yung-Yen Ko ◽  
Yu-Ying Lin
Keyword(s):  
Lateral Displacement ◽  
Free Field ◽  
Lateral Spreading ◽  
Soil Reaction ◽  
Winkler Foundation ◽  
Flexural Failure ◽  
Kobe Earthquake ◽  
Flow Displacement ◽  
Flow Pressure ◽  
Displacement Based

The lateral spreading of the ground due to liquefaction during earthquakes may considerably damage the embedded piles, which is an important issue in the seismic design of pile foundations. In this paper, nonlinear pseudostatic analyses were performed for the responses of piles subjected to actions of laterally spreading ground, which were modelled as flow displacement and flow pressure, respectively. The former is a displacement-based approach, in which the free-field ground displacement profile is assigned to the pile-soil interaction system; while the latter is a force-based approach, which regards the actions of laterally spreading ground as flow pressure and directly applies it to the pile. The concept of the Winkler foundation was utilized to account for the interaction between pile and soil. The soil springs with elastic-plastic p-y curves were used to describe the relationship of soil reaction versus lateral displacement around the pile. The distributed plastic hinges were deployed to simulate the possible flexural failure of the pile. One of the pile failure cases caused by liquefaction-induced lateral spreading in the 1995 Kobe Earthquake was adopted for case study. The analyzed pile response to flow displacement and flow pressure was compared with the field observations, and the validity and capability of both approaches were accordingly discussed. The influence of axial load on laterally loaded piles, namely, the P-delta effect was also examined. These results help to reasonably assess the performance of piles subjected to lateral spreading of liquefied ground.

Lateral spreading near deep foundations and influence of soil permeability

2017 ◽  
Vol 54 (6) ◽  
pp. 846-861 ◽  
Author(s):  
Liangcai He ◽  
Jose Ramirez ◽  
Jinchi Lu ◽  
Liang Tang ◽  
Ahmed Elgamal ◽  
...  
Keyword(s):  
Large Scale ◽  
Lateral Displacement ◽  
Free Field ◽  
Three Dimensional ◽  
Lateral Load ◽  
Lateral Spreading ◽  
Excess Pore Pressure ◽  
Fe Model ◽  
Soil Permeability ◽  
Head Displacement

A three-dimensional finite element (FE) model is calibrated based on a large-scale (1g) shake-table experiment. In this experiment, single piles were subjected to liquefaction-induced lateral spreading. The testing configuration, experimental results, and FE framework are presented and discussed. The presence of piles in this fully saturated ground model caused a significant reduction in the extent of accumulated lateral soil deformation. In this regard, high shear strains, additional to those in the free field, occur as the soil moves around the piles in the downslope direction. The associated shear-induced tendency for dilation increases the effective confinement, and reduces the resulting downslope deformations. As such, an FE parametric study is undertaken to investigate the effect of soil permeability on this observed liquefaction-induced lateral response. As the prescribed soil permeability increased (in the silt–sand range), higher levels of ground lateral deformation occured, albeit with a lower pile head displacement and lateral load. Eventually, high permeability (in the gravels range) precluded the accumulation of significant excess pore pressure, with low levels of both soil and pile lateral displacement. On this basis, permeability is highlighted as a critical potentially primary parameter in dictating the effects of liquefaction-induced lateral load on embedded foundation systems.

scholarly journals The Gujarat, West India, earthquake (Jan 26th 2001). A geodynamic event in an intraplate compressional regime?

2001 ◽  
Vol 34 (4) ◽  
pp. 1405
Author(s):  
Γ. Δ. ΔΑΝΑΜΟΣ ◽  
Ε. Λ. ΛΕΚΚΑΣ ◽  
Σ. Γ. ΛΟΖΙΟΣ
Keyword(s):  
Large Scale ◽  
Lateral Displacement ◽  
Indian Subcontinent ◽  
Plate Boundary ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Lateral Spreading ◽  
Tectonic Deformation ◽  
Epicentral Area ◽  
Surface Ruptures

The Jan. 26, 2001, Ms=7.7 earthquake occurred in Gujarat region of W. India, which lies 200-400 Km away from the active plate boundary zone, between the Indian subcontinent and the Asian plate, along the India-Pakistan border and the Himalayan belt. An Ms=7.7±0.2 earthquake also occurred in the same region in 1819. A zone of co-seismic E-W surface ruptures, 30-40 Km long and 15-20 Km wide, observed near the epicentral area and seems to be associated with pre-existing reverse faults and thrust folds, which were partially reactivated during the recent earthquake. Except the reverse vertical displacement a significant right lateral displacement was also observed along these E-W surface ruptures. This Ms=7.7 seismic event has been also accompanied by a large scale flexural-slip folding, as the absence of significant co-seismic fault displacement and fault scarp shows. This type of compressional tectonic deformation is also confirmed by the focal mechanism of the earthquake and the seismo-tectonic "history" of the area. The NW-SE open cracks, also observed along the same zone, are associated with the right lateral horizontal displacement of the reactivated fault (or branch faults) and the development of local extensional stress field in the huge anticlinic hinges of the co-seismic flexural-slip folds. A large number of ground ruptures, failures and open cracks are also associated with extensive sand boils, liquefaction phenomena and lateral spreading.

Some geotechnical aspects of the Hyogo-ken Nanbu (Kobe) earthquake of January 17, 1995

1996 ◽  
Vol 23 (3) ◽  
pp. 778-796 ◽  
Author(s):  
W. D. Liam Finn ◽  
P. M. Byrne ◽  
S. Evans ◽  
T. Law
Keyword(s):  
Soil Structure ◽  
Large Scale ◽  
Ground Improvement ◽  
Lateral Spreading ◽  
Bridge Piers ◽  
Soil Conditions ◽  
Kobe Earthquake ◽  
Port Facilities ◽  
Underground Subway Station ◽  
Directivity Effects

A geological and seismological framework is provided for understanding the damage to structures resulting from soil conditions. The paper focusses on the large-scale failures of the quay walls in Kobe Port due to liquefaction, and contrasts the performance of structures in improved and unimproved ground. Soil–structure interaction problems such as pile foundations, bridge piers, lifelines, and an underground subway station are also described. These failures have important implications for seismic design in the Fraser Delta in British Columbia, which has the potential for extensive liquefaction during a major earthquake. Key words: ground motions, directivity effects, liquefaction, lateral spreading, seismic settlements, seismic damage, port facilities, ground improvement.

scholarly journals Tree-ring response to the 1995 M<sub>w</sub> 7.2 Kobe earthquake, southwest Japan

2017 ◽  
Author(s):  
Sujian Lin ◽  
Aiming Lin
Keyword(s):  
Tree Rings ◽  
Lateral Displacement ◽  
Fault Scarp ◽  
Fagus Crenata ◽  
Southwest Japan ◽  
Fagus Crenata Blume ◽  
Kobe Earthquake ◽  
Seismic Fault ◽  
Beech Tree ◽  
Nojima Fault

Abstract. The 1995 Mw 7.2 Kobe earthquake produced an ~ 18 km-long surface rupture zone with a maximum right-lateral displacement of ~ 1.8 m along the pre-existing active Nojima Fault in southwest Japan. Field investigations showed that the co-seismic surface ruptures caused severe damage to trees, some of which survived the disaster during the past twenty years along the co-seismic fault scarp. Analysis of tree-rings from the trunk of a 46-year-old Beech tree (Fagus crenata Blume) revealed that the tree was cracked by earthquake-induced damage and that the tree-rings grown during the five-year period after the 1995 earthquake become sharply narrower in width compared to those grown before the earthquake. Our findings indicate that the earthquake damaged trees along the co-seismic fault scarp and hindered the growth of tree-rings by severing the roots. Thus, the results support the idea that older trees growing along or around fault zones can be used for identifying seismic fault events and for dendrochronological studies related to geomorphological processes.

scholarly journals Deterministic Lateral Displacement-Based Separation of Magnetic Beads and Its Applications of Antibody Recognition

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2846
Author(s):  
Haichao Zhang ◽  
Junyi Zeng ◽  
Dandan Han ◽  
Jinan Deng ◽  
Ning Hu ◽  
...  
Keyword(s):  
Driving Force ◽  
Magnetic Beads ◽  
Lateral Displacement ◽  
Low Cost ◽  
Structure Parameters ◽  
Deterministic Lateral Displacement ◽  
Antibody Recognition ◽  
Displacement Based ◽  
Two Stages ◽  
Micropillar Array

This work presents a magnetic-driven deterministic lateral displacement (m-DLD) microfluidic device. A permanent magnet located at the outlet of the microchannel was used to generate the driving force. Two stages of mirrored round micropillar array were designed for the separation of magnetic beads with three different sizes in turn. The effects of the forcing angle and the inlet width of the micropillar array on the separating efficiency were studied. The m-DLD device with optimal structure parameters shows that the separating efficiencies for the 10 μm, 20 μm and 40 μm magnetic beads are 87%, 89% and 94%, respectively. Furthermore, this m-DLD device was used for antibody recognition and separation among a mixture solution of antibodies. The trajectories of different kinds of magnetic beads coupled with different antigens showed that the m-DLD device could realize a simple and low-cost diagnostic test.

Inelastic Seismic Response of Extended Pile-Shaft-Supported Bridge Structures

2004 ◽  
Vol 20 (4) ◽  
pp. 1057-1080 ◽  
Author(s):  
T. C. Hutchinson ◽  
Y. H. Chai ◽  
R. W. Boulanger ◽  
I. M. Idriss
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Performance Measures ◽  
Soil Profile ◽  
Site Response ◽  
Free Field ◽  
Winkler Foundation ◽  
Dynamic Analyses ◽  
Inelastic Seismic Response ◽  
Motion Characteristics

Nonlinear static and dynamic analyses were used to evaluate the inelastic seismic response of bridge and viaduct structures supported on extended cast-in-drilled-hole (CIDH) pile shafts. The nonlinear dynamic analyses used a beam-on-nonlinear-Winkler foundation (BNWF) framework to model the soil-pile interaction, nonlinear fiber beam-column elements to model the reinforced concrete sections, and one-dimensional site response analyses for the free-field soil profile response. The study included consideration of ground motion characteristics, site response, lateral soil resistance, structural parameters, geometric nonlinearity (P-Δ effects), and performance measures. Results described herein focus on how the ground motion characteristics and variations in structural configurations affect the performance measures important for evaluating the inelastic seismic response of these structures. Presented results focus on a representative dense soil profile and thus are not widely applicable to dramatically different soil sites.

A Drift Pushover Analysis Procedure for Estimating the Seismic Demands of Buildings

2014 ◽  
Vol 30 (4) ◽  
pp. 1601-1618 ◽  
Author(s):  
Arash Sahraei ◽  
Farhad Behnamfar
Keyword(s):  
Lateral Displacement ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Time History ◽  
Relative Displacement ◽  
Analysis Procedure ◽  
New Method ◽  
Nonlinear Time History Analysis ◽  
Displacement Based ◽  
Nonlinear Time History

Relative displacement is a parameter that has a very high correlation with damage. The objective of this article is to develop an analysis procedure founded on the displacement-based seismic design methodology. Generalized interstory drift spectrum is applied as an essential tool in this new method called drift pushover analysis. In order to evaluate the behavior of structures, three demand parameters—lateral displacement, story shear, and plastic hinge rotation—are computed with conventional pushover analysis (CPA), modal pushover analysis (MPA), and drift pushover analysis (DPA), and are compared with those of the nonlinear time history analysis (NTA). It is observed that the new method, DPA, predicts the peak response measures more precisely and with less effort than the other nonlinear pushover procedures investigated in this study.

scholarly journals Experimental and Numerical Investigation on the Ultimate Vertical Bearing Capacity of U-Shaped Girder with Damaged Web

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3735
Author(s):  
Jingfeng Zhang ◽  
Yuan Jing ◽  
Pandao Li ◽  
Wanshui Han ◽  
Nan Zhang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Failure Process ◽  
Ultimate Bearing Capacity ◽  
Railway Transportation ◽  
Transit System ◽  
Flexural Failure ◽  
Significant Difference ◽  
Thin Walled ◽  
Displacement Based ◽  
The Web

U-shaped girder has been extensively used for its excellent adaptability in the urban railway transit system. As an open thin-walled structure, significant difference of working mechanism exists between U-shaped girder and conventional section girder (e.g., T section or box section). The thin-walled web plays significant role in the flexural performance of U type girder particularly. Moreover, severe collision may occur between the moving train and the girder, and subsequently results in the decrease of the structural bearing capacity. In this paper, a full-scale test was carried out to examine the ultimate bearing capacity and the failure mechanism of the U-shaped girder, and a refined numerical model was developed to simulate the damage evolution and the failure process. It was shown that the flexural failure occurred on the U-shaped girder under vertical loads. In addition, the ultimate bearing capacity of the structure under different web damage conditions (e.g., web damaged region or damaged range) was studied by applying the displacement based lateral load on the flange of the U-shaped girder to simulate the damage caused by accidental train collision. The numerical results have shown that the damaged web greatly affects the ultimate bearing capacity of U-shaped girder, more severe bearing capacity descending occurs around the middle span rather than the beam ends. The damaged range (length) of the web has less influence on the falling amplitude of bearing capacity. It can be concluded that the major reason accounting for the bearing capacity decrease is that the original section is weakened by the web damage, and consequently results in the buckling of the damaged web and lead to the total failure of the structure. It is recommended that the lateral resistant design for the web should be taken into consideration to ensure the operation safety of the urban railway transportation.

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