Dead load (kentledge) A structure over the test pile Ground

Transcription

Introduction
Fugro LOADTEST Overview
Static load tests
Previous/existing technology
Developments
STATIC LOAD TESTING
O-cell® BiBi-directional testing
State of the art
Dr Melvin England
Fugro LOADTEST
O-cell® static loading tests
Conclusions
Date 27th January 2010
www.fugro.com www.fugro.fr
LOADTEST Inc started in 1991
Operating around the world from 5 LOADTEST offices
45 staff – mostly engineers
– Some of our staff are recognised leading experts in
various forms of pile testing
€10 M turnover (1/2 USA)
Portable test systems allow easy access to very remote
locations
LOADTEST acquired Fugro as new owners in Jan 2009
and LOADTEST can now operate from any of the Fugro
offices around the world and call on the resources of
Fugro where necessary.
Oil-rig module used as Kentledge
Date 27 January 2010
Reaction systems for static load tests:
Fugro LOADTEST
Dead load (kentledge)
A structure over the test pile
Ground anchorage either by
tension piles or ground anchors.
Bi-directional (Osterberg-cell)
Test on group of 9 precast piles to 20MN
1
Ready assembled reaction systems
Reaction systems
BiBi-directional testing ABU-DHABI
2MN
4 MN
5.5 MN
10 MN
GREAT MOSQUE ABU-DHABI
SHEIKH ZAYED BRIDGE
ABU-DHABI
Zone of influence
Zone of influence
Kentledge
Reaction beam on anchor piles
Zone of influence
Zone of influence
Kentledge on piles
Bi-directional
test
2
Kentledge collapse
Safety considerations
Due to platform/ground failure
From FPS Load testing handbook 2006
Reaction Beam collapse
COMPLETELY AUTOMATED
Due to tension bar failure
From FPS Load testing handbook 2006
BIBI-DIRECTIONAL OO-CELL LOAD TESTS
How it works
Introduction To Osterberg Cell
technology
Advantages & Limitations
Examples
Current usage and costs
3
Bi-directional schematic
Bi-directional schematic
Comparison of O-cell and Traditional Tests
O-cell Static Load Test Advantages

Very high loading capability
Gets load into rock sockets (or other zone of
interest)

Cost, safety and space advantages

No additional reaction system needed

Doubles effective jack load

Can measure directly skin friction and end bearing
Post-test grouting techniques allow for testing of
production piles

Single O-cell – Bearing Plate Assembly
O-Cell Instrumentation
Top and Bottom Plates are Welded to the O-cell
O-cell / Plate System is Welded
into the Rebar Cage
4
O-cell Test Components
O-cellTM fitted with bearing plates attached to cage
MultiMulti-cell assembly - attaching OO-cells to bottom plate
Cone-shaped
tremie guide
MultiMulti-cell assembly - attaching top plate
Other O-cell Assemblies
Lifting the Cage and Attached O-cell Assembly
Once the Cage With Attached O-cell is Carefully Lifted, it is Installed into the Shaft Excavation
O-cells can be Placed at two Levels in the
Shaft to Isolate Distinct Shaft Elements
The O-cell Need Not be Attached to a Rebar
Cage
5
Multilevel testing
Multilevel testing Stage 1
Middle cell closed
Test is performed in stages
Lower cell pressurised
Downward movement below bottom O-Cell
Middle cell pressurised
(MN)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0
-10
-20
-30
-40
Lower cell draining
-50
-60
-70
Downward movement below middle O-Cell
(MN)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
Middle cell pressurised
0
-5
-10
-15
-20
-25
-30
Lower cell hydraulically closed
-35
-40
-45
6
30
25
20
Downward movement below middle O-Cell
15
(MN)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
10
0
5
-5
0
-10
0.0
-15
-20
-25
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
(MN)
End of Stage 2 testing, Bottom
O-cell hydraulic lines closed allowing load transfer to end
bearing.
Upward movement above middle O-Cell
-30
-35
-40
-45
Test Setups
Equivalent top load-settlement curve
Load (MN)
Settlem ent (m m )
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
110.0
120.0
130.0
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
World record – 160 MN
Advantage – Space Requirements
O-cell Test Limitations
Preselected shaft
2000 ton Conventional
3000 ton Conventional
Maximum load limited by weaker of end bearing
or skin friction
Test results need interpretation
Top of the pile is not tested structurally tested
2000 ton
O-cell Test
3000 ton
O-cell Test
Top load movement curve must be calculated
From the sum of measured behaviour;
From the sum of modeled behaviour;
Finite element;
7
Analysis of O-cell test results
Equivalent TLT Assumptions
‘Rigid’ shaft (includes OLT elastic compression)
L-Movement compatibility, friction and end bearing
Corrections for direction of skin friction
Factor = 1 clays, rock sockets
Correction for direction of loading can be used
Factor = 0.80 Equivalent tension test
Correction for additional TLT elastic compressionconservative, iterations not needed
Good practical agreements
Sum of measured results
Measured behaviour Sum of components
Measured plus additional elastic shortening
Comparison test curves
Kentledge Test versus O-cell equivalent top load-settlement curve
0
-10
-20
Settlement (mm)
-30
O-cell Test
Kentledge Test
-40
-50
-60
-70
-80
-90
-100
-110
-120
0
2
4
6
8
10
12
14
16
18
Top Load (MN)
20
22
24
26
28
30
8
Advantage – High Loads
Incheon 2nd Link, Korea
World Record History
Location
Diameter
Depth
Maximum Load
Ohio River Bridge,
Kentucky ( 1992 )
1.8m ( 6 ft. )
36m ( 117 ft. )
54 MN ( 6,200 tons )
St. Mary’s River, Georgia
(1996 )
1.5m ( 5 ft. )
23m ( 75 ft. )
65 MN ( 7,300 tons )
Penang, Malaysia
( 1996 )
6x1m barrette
91m ( 300 ft. )
97 MN ( 11,000 tons )
Apalachicola River, Florida
( 1997 )
2.75m ( 9 ft. )
39m ( 127 ft. )
133 MN ( 15,000 tons )
Tucson, Arizona
( 2001 )
2.4m ( 7.9 ft. )
41m ( 135 ft. )
151 MN ( 17,000 tons )
Pomeroy - Mason WV,
Ohio River
2.4m (8 ft.)
26m (86ft.)
163 MN (18,400 tons)
2nd
2.4m – 3.0m
(8 ft. – 10ft.)
67m (220ft.)
279 MN (31,350 tons)
Crossing
Incheon
Korea
Oste rbe rg Ce ll Loa d-Move me nt Curve s
Advantage – Rock Sockets
60
OLT
TLT
50
P
40
Displacement ( mm)
30
Overburden
20
Upwar d Top of O- c ell
10
0
-10
Downwar d Base of O- c ell
Rock
-20
Q
Ub & Eb difficult to interpret
-30
-40
0
20
40
60
80
100
120
140
160
• Uncertain Distribution
• Less Distribution Uncertainty
• Little or No Top Load Gets into base
• All Load into Socket
• May Need Model Shaft
• Can Test Full Scale
O-ce ll Gr os s Load ( M N )
9
Applications
O-cells in CFA piles
Bored piles (wet and dry)
CFA piles
Driven Piles
– Cast in-situ (with and without
permanent steel casing)
– Precast
– Steel tubular piles
Barrettes
Maximum size/loads tested to date
Pile Diameter [mm]
Pile Length [m]
O-cell Diameter [mm]
Mobilised Load [MN]
O-cells in PRECAST piles
600
750
900
900
38
40
35
36
405
540
660
2x540
17.5
32
32
46
Barrettes
Sizes tested
to date
Pile Section
300 mm
450 mm
600mm
750 mm
10
St. Petersburg, Russia
St. Petersburg, Russia
30 MN Reaction system
• 60 m deep
90 MN O-cell test
• 90 MN capacity
Kiev Ukraine: 90 MN Barrette
7.0m x 1.2 m
50 m deep
loaded to 110 MN
T shaped:
2.8 x 4.0 m
Multiple tremie pipes
loaded to 70MN
Applications: Bridges
Cooper river
Jiangsu Sutong
Panama 2nd Bridge
Confederation
UAE: Multilevel; 80 m deep; 220 MN mobilised
11
Applications: Buildings
Osterberg Cells Installed
Actual
Projected
350
300
250
200
150
100
09
08
20
20
06
05
04
07
20
20
20
20
02
01
00
03
20
20
20
98
99
19
20
96
97
19
19
19
94
93
95
19
19
19
92
0
19
Venetian Hotel,
Las Vegas, NV
50
91
Four Seasons
Hotel
Miami, FL
19
One Raffles
Quay,
Singapore
O-cell Tests World-wide
COMPARISON OF LOAD TESTING COSTS
CONVENTIONAL VS. O-CELL
O-cell
COST/ MN
Conventional
Key
0
1-10
11-20
21-30
>30
Upcoming/In
progress
1
10
100
1000
TEST LOAD - MN
Bi-directional testing
Disadvantages
•No external reaction
system
•Pile test not exactly
as a full load test.
•No anchor piles
•Maximum load
applied limited
•Only half the stresses
applied to the concrete
•For large tests a
significant cost saving
Conclusions
Advantages
•Little or no heavy
transport requirements
Bi-directional testing routinely reveals more about the
geotechnical behaviour than a traditional top-down
loading test. (Over 1400 tests worldwide).
O-cell testing much safer than traditional top-loading
•Jack is expendable
and needs fitting
during pile
installation
As the test loads increase the more cost effective and
attractive O-cell testing becomes.
12
Providing confidence in foundations through
load testing - around the world.
www.loadtest.com
Thank You
A member of the Fugro Group of companies
Florida, USA
UAE
LONDON
SINGAPORE
KOREA
Date 27th January 2010
13

Dead load (kentledge) A structure over the test pile Ground

Transcription

Similar documents

CK2500-II Spec Book 12-05

HYDRAULIC CRAWLER CRANE CK2500