This is my first paper, not really good, I made it just for about 1 day.. This is the requirements from my lecturer to get a midtest.. It was just like pre-mid test.. If there is any mistak…Full description
Description complète
This presentation describes about digital forensic with pratical and academic approach such as digital forensic procedure and support in order to give a comprehensive description to the user…Full description
Guidelines
ThermoelectricsFull description
A fantastic lecture by world renowned clinician Tara Aghaloo from LA, taking place next month at the Dakota hotel between Edinburgh and Glasgow.Full description
deep stateFull description
A beautiful book by Eric Hoffer, an American thinker and philosopher.
A Comprehensive Guide to Modern Air Combat. Written by Pete Bonnani and Col. Handley. This document details Aerial combat, from Basic Fighter Maneuvering to Beyond Visual Range maneuverin…Descrição completa
The Art Of Nude - Early XX CenturyFull description
tsukamakiFull description
How to kiss video subtitlesFull description
Soil reinforcement by vertical stiff inclusions i France in F François SCHLOSSER Bruno SIMON
1
• • • •
Interaction mechanisms Some landmark applications R i off practice Review ti and dd design i approach h Further research
2
• • • •
Interaction mechanisms Some landmark applications R i off practice Review ti and dd design i approach h Further research
3
A compound foundation system
9 Stiff inclusions 9 Pile caps 9 Reinforcement (occasionally) 9 Granular G l mattress tt 9 Floor slab (occasionally) … Pile supported earth platform … Piled Pil d embankment b k
4
Shear mechanism overview • Piled embankment
Upper equal settlement plane
Lower equal settlement plane
5
Shear mechanism overview • Piled embankment
6
Shear mechanism overview • Pile supported earth platform foundation
On going work adaptation (1995) • Grasse Court Hall
Jet Grouted Columns 16
Fill behind quay wall (2001)
Continuous auger concrete piles (Starsol®) 17 1.4 m square pile caps and wiremesh reinforcement
Floor slab full scale load test (2001)
Controlled Modulus Columns (CMC®)
18
Heavily loaded industrial slab (2000)
Controlled Modulus Columns (CMC®)
19
Outstanding work and environment (2004) • Rion Antirion bridge
2 m diameter open steel piles square grid 7 m x 7 m 20
Validation of an innovative concept Pecker A. : capacity design • Numerical modelling – Yield design approach of limit loads – FE models to check limit loads and evaluate displacements
21
Validation of an innovative concept Pecker A. : capacity design • Numerical N i l modelling d lli • Physical modelling – 100-g 100 centrifuge if testing i (Nantes (N LCPC facility) f ili ) – Reconstituted soil
22
• • • •
Interaction mechanisms Some landmark applications R i off practice Review ti and dd design i approach h Further research
23
Installation technique development • Many proprietary equipment (VCC, Starsol, CMC)
24
Comparison with other practice 2.50
2 50 2.50
HR/S
HR/S 2.00
2.00
HR
1.50
1.50 1.00
1.00
0.50
0.50
area ratio (%)
area ratio (%)
0.00
0.00
0
5
10
15
20
25
30
S
0
5
10
15
20
25
International review (published)
French practice (Briançon, 2002)
HR = 1.1 to 2.2 m
HR = 0.4 to 0.9 m
Geosynthetic reinforcement
No geosynthetic reinforcement; sometimes welded wiremesh
Mostly piled embankments for roads and railways
Floor slabs and rafts (warehouses, stores, storage tanks) 25
30
Pile reinforcement design • Pile – Type andd installation i ll i method h d – Constitutive material: strength and stiffness – Addition of a pile cap or not • Geometry – Mesh shape and size – Pile embedment in the bearing stratum • Transfer layer – Quality and thickness – With additional reinforcement elements or not
26
qo
Reinforcement design g checks (Q*)
qs+
Qp+
active
Hc
• Percentage coverage of pile caps α = a2/s2 • Stress reduction ratio – SRR = qs+/q0 • Efficacy – E = Qp+ /Q*
Qmax
passive
• Critical height Hc • Maximum axial load Qmax – Qmax < Qlim / γ
Qlim
a
s
• Settlement at surface – yp(0), ys(0)
27
Design methods in use State of the art review (Briançon, 2002) g approach pp of the whole foundation system y • Integrated – Methods stemming from work on negative skin friction (Combarieu) (step by step) – Numerical FE or FD methods • Homogeneization H i ti methods th d – Main focus on average settlement
28
Negative skin friction Combarieu (1974) • Assumes shape of vertical stress field between piles – Parameters Ktanδ, λ
Global numerical methods Finite element and finite difference methods
Plaxis 2D 2D strain plane model
Elementary cell (axisymmetric) 35
2D model shortcomings • Plane strain models – No straight definition of equivalent « wall » properties • Contradicting scale perimeter and area conditions • How to scale interface properties ?
– Limited stress rotation above pile heads – Yet can cope with non uniform or lateral loading • Axisymmetric models – Axisymmetric A i t i vertical ti l loading l di off a central t l cell ll only l – Approximation to a square mesh 36
3D numerical models
FLAC 3D (explicit finite difference)
37
3D numerical models • Advantages – Any geometry – Any kind of loading – All interactions properly taken into account • Interfaces and mesh refinement required
• Limitations – Heavyy input p and output p pprocessing g – Time and memory consuming – Increased complexity with non uniform loading or to study side effects – Use is limited to research or outstanding works 38
3D numerical models • A promising way : embedded elements – Sadek S d k (2004)
39
Requirements for all numerical models • Choice of adapted constitutive laws – Granular fill : • Characterization of a coarse material • Non linear behaviour with strong stress path- and stress level-dependency • Ability Abilit to t depict d i t 90° rotation t ti off principal i i l stress t directions di ti
– Soft soil • Yield stress, consolidation and creep process
• Interface properties – Should reflect the ppile installation technique q and degree g of soil disturbance – Need of experimentally validated laws • Fill placement – Compaction effect – Contribution C t ib ti off any geogrids id 40
Homogeneization - 1 EpAp E hom =
+ Es As
β A p + As
Slip along pile → β = 40
No access to pile stresses Anisotropy ignored
Ehom Single cell adjustment
Equivalent E i l t failure f il criterion it i
Extended equivalent model 41
Homogeneization - 2 Two Phase model (de Buhan, 2000)
• All interactions i t ti introduced i t d d – Specific factors α • Boundary conditions ii – Load fraction λ 42
• • • • •
Interaction mechanisms Some landmark applications R i off d Review design i approach h Some at border cases Further research
43
State of the Art review (Briançon, 2002) • Limited amount of available experimental data • Mainly focus on load transfer within granular layer in presence of one or more geogrids • Preeminent use of pile supported earth platforms / piled embankments p • No widely accepted simple design method for ordinary projects • Wide scatter of results for the calculated efficacy
44
Other points • C Can shear h effects ff t b be partly tl d destroyed t db by vibrations ib ti of travelling loads? • Minimum quality requirement for the mattress (cost of granular fill becomes high in urban areas) ? • How to include fill compaction effects in design? • Seismic behaviour for ordinary works ?
45
ASIRI project (2005- 2009) 2.4 M € state and industry funded research project • Led by a non profit organization (IREX) – With managing and scientific committees • Independent network of owners, consultants, contractors and academics (40 company core members) g g Research label • Civil and Urban Engineering
46
ASIRI project (2005- 2009) • Full scale experiments : 2 x 5 trial embankments y modelling g • Physical – Centrifuge testing (100g facility in Nantes) – Calibration cell tests and 2D analogical tests • Numerical modelling – To develop 3D FEM and FD reference models – Other models : biphasic models, discrete models – To evaluate simple design methods currently in use 47
ASIRI project (2005- 2009)
15 m
• Full scale testing – Pile supported earth platform (now in progress)
– Piled embankments (scheduled 2007, other site)
48
ASIRI project (2005-2009) • Recommendations about use and design of pile supported earth platforms for spread foundations and piled embankments – Efficient and easyy to use design g methods • For evaluating stresses, displacements, safety • For optimization p off this foundation f system y
– With validity checked against • all collected experimental data • results of the more sophisticated numerical models 49