Evolution of the Foundation Industry Met Miami Development Miami, Florida

cypriotcamelΠολεοδομικά Έργα

29 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

91 εμφανίσεις

Evolution of the
F
oundation
I
ndustry
M
et

Miami

D
evelopment

M
iami,
F
lorida

Carlos Ortiz, P.E. & Matthew Meyer, P.E.

Langan Engineering and Environmental Services, Inc.

Presentation Outline


Evolution of South Florida & ACIP Piling Industry


Projects, Piling Rigs, Material, AME, NDT,
Geology, & Design



Met
-
Miami Development


Design evaluation & foundation selection


Test pile and load testing programs


Adjusted pile embedment & capacities for largest
ACIP Piles


Production installation issues for larger piles

Downtown Miami (early 1970s)

Miami Metrorail (Early 1980’s)

Beach
-
Front Structures (Late
1980’s)

Oceania Towers
-
Sunny Isles Beach

Bal Harbour Tower, Bal Harbour, FL

Downtown Miami (late 1990s to early 2000s)

Evolution of ACIP Piles in South Florida

90
80
400
440
150
100
85
60
40
60
220
200
100
100
700
440
0
200
400
600
800
1000
1200
1980
1983
1988
1994
1996
2000
2004
2002
Year
Capacities (tons) / Lengths (ft)
Typical Pile Lengths (ft)
Compressive Capacity (tons)
14-inch-dia 16-inch-dia 18-inch-dia
24-inch-dia
30-inch-dia
Reference


O
-
cell Tests on Augered Cast
-
in
-
Place Piles, Edwin W. Hickey and Andres M. Baquerizo of HJ
Foundation, and John Hayes of Loadtest, presented in DFI’s Augered Cast
-
in
-
Place Pile Committee
Specialty Seminar: Augered Cast
-
in
-
Place Piles on June 22, 2007 in Coral Gables, FL.

Biscayne Avenue Area (2008)

Evolution of Higher Capacity ACIP
Piles in South Florida

90
80
120
150
120
400
440
700
700
1,200
150
100
85
60
40
60
220
200
100
100
700
440
0
200
400
600
800
1000
1200
1980
1983
1988
1994
1996
2000
2004
2002
2004
2005
2006
Year
Capacities (tons) / Lengths (ft)
Typical Pile Lengths (ft)
Compressive Capacity (tons)
14-inch-dia 16-inch-dia 18-inch-dia
24-inch-dia
30-inch-dia
36-inch-dia
Reference


O
-
cell Tests on Augered Cast
-
in
-
Place Piles, Edwin W. Hickey and Andres M. Baquerizo of HJ
Foundation, and John Hayes of Loadtest, presented in DFI’s Augered Cast
-
in
-
Place Pile Committee
Specialty Seminar: Augered Cast
-
in
-
Place Piles on June 22, 2007 in Coral Gables, FL.

South Florida Geology and
Subsurface Conditions

Reference


Frizzi, R.P. and Meyer, M.E., “Settlement of Tall Buildings Supported on Deep
Foundations in Southeast Florida, USA”, DFI’s 28
th

Annual Conference, Miami Beach, FL, 2003.

ACIP Piling Rigs (Fixed Mast Vs.
Swinging Leads)

Material, Equipment & Design
Evolution


Large, high
-
capacity cranes fitted for ACIP Piling
equipment


Increased grout pump capacities


Highly fluid and high strength grouts mixes


Increased auger diameters and advanced tooling


High torque and crowd rigs


Significant body of knowledge in geotechnical and
structural community


Numerous publications on design of cast in place piling
systems


Settlement performance of buildings up to 70+ stories
on deep foundations is well documented





Pile Installation Recorder for ACIP Piles

1.
Main Controller

2.
Depth Reel

3.
Grout line Pressure


4.
Magnetic Flow Meter

5.
Torque Pressure

6.
Auger Rotation

5

1

2

4

4

2

3

6























Automated Monitoring (PIR
-
A)

Grout Hose Pressure/Volume Gage

Drilling Depth Gage

Cross
-
Hole Sonic Logging (CSL) Pile

Four full
-
length 3
-
inch
-
dia
steel pipes were attached to
the cage for cross
-
hole sonic
logging to verify pile integrity.

Met
-
Miami Site (2000)

Met Miami


Proposed Development

Met
-
1

Met
-
2

Met
-
3

Met

Square

Met
-
1/Met
-
Square


Jan 2004 Geotechnical Study


Subsurface Conditions


Middle Rock (top encountered at
el
-
22 to
-
33)


Deeper Rock (top encountered
at el
-
73 to
-
88)


Reclaimed Biscayne Bay portion
(bay bottom sediments and very
thin top rock); rest of the site
included the top rock



Typical South Florida
Subsurface Conditions

Met
-
1/Met
-
Square Foundation
Recommendations


Met
-
1 (42
-
Story Tower)


Tower = 24
-
inch
-
dia, 420
-
ton piles drilled into
deeper rock


Podium = 18
-
inch
-
dia, 220
-
ton piles drilled
into middle rock


Met
-
Square


Shallow footings bearing on top rock


Predicted Tower Settlements (1 to 2 in)

Met
-
1 Pile Load Test Program


Pile Load Testing Program (Late 2004)


24
-
inch
-
dia compression, tension, and lateral


18
-
inch
-
dia compression and tension


Top load testing due to Client’s hesitancy
regarding O
-
Cell load testing


O
-
cell testing on ACIP piles had only been
implemented on one or two projects previous
to Met
-
1 test pile installation


24
-
inch
-
dia Compression Load Test

0.00
0.50
1.00
1.50
2.00
2.50
3.00
0
105
210
315
420
525
630
735
840
945
1050
SETTLEMENT (inches)


LOAD (tons)

Standard Load
Overloading
Pile Type:

24
-
inch
-
diameter ACIP

Pile Length:
92 ft

Tip Elevation:
el.
-
86 ft, NGVD

Test Type:

Standard Compression

Load Transfer Limitation


Before O
-
cell load testing became available of
ACIP piles, the only option was top load testing.


Top load testing of long piles becomes
confirmation load testing and cannot be used to
confirm rock socket design side shears.


It was common for us to see that only 5 to 10
percent of the load was being transferred to the
rock socket.

Met
-
3


74
-
story hotel tower


15
-
level podium


Geotechnical Study
(Late 2004


Early
2005)

Met
-
3 Subsurface Conditions


Middle Rock


Top encountered at el
-
32 to
-
44


Highly variable thickness (4 to
22.5 ft thick)


N
-
values = 9 to 100+ blows/ft
(average 44 blows/ft)


Lower Rock


Top encountered at el
-
80 to
-
89


N
-
values = 16 to 100+ blows/ft
(average 74 blows/ft)


Typical South Florida
Subsurface Conditions

Met
-
3 Foundation
Recommendations


Tower (Dual Design)


First Alternative = 6
-
foot
-
dia, 1,800 to 3,000
-
ton drilled
shafts drilled into deeper rock


Second Alternative = 36
-
inch
-
dia, 1,000
-
ton piles drilled
into deeper rock (had not been installed before)


Podium


Combination of shallow footings and 24
-
inch
-
dia, 400
-
ton
piles drilled into middle rock, with additional short 16
-
inch
-
dia tension anchors


Predicted Tower Settlements (3 to 4 in)

Drilled Shaft Design Alternative


6
-
foot
-
dia drilled shafts


Recommended embedment into deep rock
(≈ 125 to 145 ft long)


Compression capacity = 1,800 to 3,000 tons


Tension capacity = 800 tons


Total # of drilled shafts = 124 shafts


Construction duration estimate = 250 rig days


Original ACIP Pile Design
Alternative


36
-
inch
-
dia ACIP piles


Recommended embedment into deep rock
(≈ 110 to 120 ft long)


Compression capacity = 1,000 tons


Tension capacity = 400 tons


Center
-
to
-
center spacing = 2.5d to 3d


Total # of piles = 308 piles


Construction duration estimate = 90 rig days

ACIP Piles vs Drilled Shafts

Legend
-

36
-
inch
-
dia piles 6
-
foot
-
dia drilled shafts

Met
-
3 Pile Load Test Program


Initial Pile Load Testing Program (Early 2006)


Start with indicator pile to prove that it could be
installed


If successful, install additional piles


Multi
-
Level Simulation O
-
cell Pile


Multi
-
Level 36
-
inch
-
dia O
-
cell Test Pile


Cross
-
Hole Sonic Logging Pile


Communication Assessment Pile


Use of Automated Monitoring System (PIR
-
A)




Additional Test Pile Program


Additional load testing program for the
podium piles has not been performed yet


24
-
inch
-
dia compression and tension


16
-
inch
-
dia tension


To be performed as top load tests

Multi
-
Level Simulation Pile

A simulation pile was installed as a
trial prior to drilling and installing
the actual O
-
cell test pile.

Multi
-
Level O
-
cell Test Pile

Multi
-
Level O
-
cell Load Testing

Set
-
up and Procedure


Estimates of side shears are necessary to
select the O
-
cell locations.


Stage 1


Mobilize the bottom pile section
until sufficient movement is measured and
the ultimate side shear is attained.


Stage 2
-

Create a soft bottom condition by
opening the pressure lines leading to the
lower O
-
cell (allowing the lower O
-
cell to
close) and load the upper O
-
cell to engage
the middle section.


Stage 3
-

Perform pile compression test to
confirm modulus.


Key


The rock has to cooperate (cannot be
much stronger or weaker than expected).

Upper
O
-
cell

Lower
O
-
cell

1655 kips

O
-
cell Load Testing Results

(Multi
-
Level)

O
-
cell Load Testing Results

(Multi
-
Level)

3867 kips

Met
-
2


47
-
story office tower


44
-
story hotel tower


19
-
level podium
connecting the towers


Geotechnical Study
(2006
-
2007)

Met
-
2 Subsurface Conditions


Middle Rock


Top encountered at el
-
25 to
-
36


5 to 15 ft thick


N
-
values = 17 to 100+ blows/ft
(average 37 blows/ft)


Lower Rock


Top encountered at el
-
81 to
-
88


N
-
values = 14 to 100+ blows/ft
(average 47 blows/ft)



Typical South Florida
Subsurface Conditions

Met
-
2 Foundation
Recommendations


Office and Hotel Towers


36
-
inch
-
dia, 1,000 ton piles drilled into deeper rock


Podium


combination of 36
-
inch
-
dia, 1,000 ton piles drilled into
deeper rock and 18
-
inch
-
dia, 200
-
ton piles drilled into
middle rock


Estimated Settlements


Office Tower = 2 to 2½ inches


Hotel Tower = 1¾ to 2¼ inches

Met
-
2 Load Testing Program


36
-
inch
-
dia O
-
cell Test Pile (single level)


24
-
inch
-
dia O
-
cell Test Pile (single level)


18
-
inch
-
dia compression and tension top
load tests


24
-
inch
-
dia test was performed because
this diameter was being considered
previously for a shorter hotel tower

Single
-
Level O
-
cell Load Testing
Set
-
up and Procedure


Estimate of side shear below the O
-
cell
is necessary to select the O
-
cell
location.


Load the pile by opening the O
-
cell
and “splitting” the pile apart.


As would be the case in any load test,
use strain gages to calculate load
distribution and side shears along
different pile sections (concentrating
on the rock socket).

O
-
cell

2945 kips

36
-
inch
-
Dia Single Level O
-
cell
Load Testing Results

24
-
inch
-
Dia Single Level O
-
cell
Load Testing Results

1492
kips



Evaluation of Test Results & Adjustments
to 36
-
inch
-
Dia Recommendations


The evaluation of the test pile observations
and results included the following:


How did the test pile drill as compared to other
piles (Drilling times
-

test pile vs other piles)


Drilling times and load testing results were
compared to conditions observed at borings to
determine side shear profile to reevaluate the
rock embedment

Drilling Times vs Subsurface Profile

Reduced embedment to 20 ft. This would have resulted in savings
of ≈ $300,000 (load test program would pay for itself).

-110.0
-105.0
-100.0
-95.0
-90.0
-85.0
-80.0
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Time (minutes)
Elevation (ft, NGVD)
Average
Maximum
Minimum
O-CELL Pile
Final Re
-
Evaluation


Increase 36
-
inch
-
dia capacity to 1,200 tons


agreement with structural engineer to account for
building code increase to include steel and not just
grout on the pile stress calculation (0.25 f’
grout

+0.34
fy
steel


limiting steel yield strength to 25,500 psi).
This building code change became in effect after
original design.


embedment back to 25 ft into the deep rock


Note


Most recent additional increase in building code
allowed stresses on ACIP piles could have allowed an
even higher pile capacity.

Revised ACIP Pile Alternative


36
-
inch
-
dia ACIP piles


Recommended embedment into deep rock
(≈ 110 to 120 ft long)


Compression capacity = 1,200 tons


Tension capacity = 400 tons


Total # of piles = 235 piles

ACIP Pile Layout

(1,200 tons, 36
-
inch
-
dia piles)

235 piles vs. 308 piles (Savings = $1.5 million and 20 rig days)

Settlement Behavior Comparison

0
0.5
1
1.5
2
2.5
3
0
10
20
30
40
50
60
70
Settlement (in)

Elevated Slabs

Met 1
Met 2 Office
Met 2 Hotel
Four Seasons
Ten Museum Tower
66
-
Story Tower

48
-
Story Tower

Production Installation Issues


Production rates (3 to 4 piles per day)


Predrilling requests/considerations


Grout amounts (4 to 5 trucks per pile)


Pumping times ≈ 15 to 20 minutes (grout fluidifier
required)


Grout drop after completion


High
-
strength grout compressive strength
guarantees (56
-
day vs 28
-
day)


applies to 7,000
psi and higher


An additional full
-
time crane is necessary to handle
cages

Conclusion


ACIP Pile Industry Has Improved Significantly


ACIP Piles Are Practical Alternative For 60 to
75
-
story High Rises Previously Supported on
Drilled Shafts


O
-
cell Load Testing is Critical for Optimization of
Foundation Designs


Side Shear Resistances & Settlement
Performance are Well
-
Documented


Larger/Longer Piles are Being Considered and
Could be Available for Future Booms