13/04/2015
Marina Bay Sands Integrated Resort
The design and construction of the
16 hectare basement at Marina Bay Sands,
Singapore
16th Mar 2015
Jack Pappin
2
600m
• Ground conditions
• Excavation sequence (area by area)
• Issues (area by area)
3
Overall Development at Marina Bay Sands Integrated Resort
4
Overview of presentation
1
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5
Plan of 16 hectare excavation
6
Geological sections
 Thick deposit of soft clay.
 Severe time constraints
- More than 40% of concrete construction works for substructure
- Minimise inter-dependency between different contracts.
 Movement control for existing structures (ECP and BSB).
 Very limited site access.
7
Challenges for Excavation Works
8
Layout of excavations
Site
access
2
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Circular
Cofferdams
Jul 2007
9
View of site access
10
Minimum use of strutting
Site
access
Design
Jan 2008
Effective Wall Thickness
To take into account:
• Plan offset at commencement level
• Verticality tolerance
Design wall
alignment
t
t = Wall thickness
teff
t
PLAN
teff = Effective wall thickness
Maximum Hoop stress ~ K0 insitu stress * R / teff
11
MICE & Hotel Donuts & Hotel Peanut
12
Design of Circular walls
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As shear stress and in plane
compression stress are
mutually dependant the
BS8110 friction coefficient for a
plain concrete joint was used
iteratively in the SAP analysis.
3-D Analysis for Peanut Cofferdam
1.
13
Obtain different earth pressures from
OASYS FREW to account for
variation in geology.
2.
Set up 3-D Finite Element Model
SAP2000 to assess stresses and
deformation shape of the cofferdam
3.
Structural design of diaphragm wall
panels, cross wall and fin wall.
Design of Circular walls
8m wide 15m deep
cantilever fin walls
Cross wall
Location of peak
inter panel shear
14
Design for shear in peanut cross wall
Crystal pavilions
Promenade
Museum
Retail
Theatre
MICE
Casino
Hotel
Tower 1
15
Construction sequence – South Podium
16
Hotel
Tower 2
Hotel
Tower 3
Construction sequence – South Podium
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Existing
Ground Level
Retail
STAGE 1:
MICE
RL(m)
RL(m)
110
110
Sea
100
Existing
Ground
Level
Existing
Ground
Level
Existing
Ground Level
Diaphragm
wall
MICE
Retail
99.5
mRL
1. Install diaphragm wall, jet grout and bored
piles.
2. Excavate along perimeter of circular
cofferdam to construct capping beam.
MICE
Retail
Capping beam
Capping beam
Diaphragm
wall
100
Fill
90
80
90
Proposed excavation level
Sand
Sand
80
6m
thk.
Jet
grout
Soft clay
70
70
60
4m
thk.
Jet
grout
60
Old Alluvium
50
50
40
40
17
Construction sequence – South Podium
18
Bored piles
Construction sequence – South Podium
STAGE 2:
STAGE 3:
1. Excavate to final excavation level inside
cofferdams.
2. Install top down columns.
1. Install steel truss at +100mRL using trench
method.
2. Construct part of L1 slab as construction
access.
3. Cast base slab in cofferdams.
B2 FEL
(~+90.5)
B4 FEL
(~ +86.0)
B4 slab
RL(m)
RL(m)
Retail
110
MICE
Top down column
Retail
110
100
100
MICE
L1 slab for construction access
Steel truss
Steel truss
FEL
B2 slab
90
90
Sand
Sand
80
80
70
70
60
60
50
50
40
40
19
B2 slab
Construction sequence – South Podium
20
Construction sequence – South Podium
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B2 FEL
(~ +92.5)
STAGE 4:
1. Excavate to final excavation level in MICE
and +91mRL in the remaining areas outside
cofferdams.
2. Construct basement structure inside
cofferdams.
+91mRL
Construct
basement
slabs
above B4
Construct
L1 slab
+91mRL
B2 FEL (~ +90.5)
RL(m)
Retail
110
STAGE 5:
B4 FEL
(~ +86.0)
B2
Slab
RL(m)
Retail
110
MICE
B4 FEL
(~ +86.0)
1. Cast B2 slab in MICE.
2. Install struts in the remaining area below B2
soffit.
3. Excavate to final excavation level in the
remaining areas.
B4 FEL (~ +86.0)
MICE
L1 slab
100
100
Strut below B2
FEL
90
Sand
Sand
80
80
70
70
60
60
50
50
40
40
21
B2 slab
FEL
90
Construction sequence – South Podium
22
Construction sequence – South Podium
B4 slab
STAGE 6:
STAGE 7:
B4 slab
1. Cast B4 slab.
1. Complete L1 slab.
2. Install struts across the openings of L1 in
Retail.
3. Remove steel truss.
B4 slab
RL(m)
Retail
110
100
MICE
B4 slab
L1 slab
MICE
Strut at L1
90
Sand
Sand
80
70
70
60
60
50
50
40
40
Construction sequence – South Podium
L1 slab
previously cast
L1 slab previously cast
Retail
110
80
23
L1 slab
previously cast
RL(m)
100
90
G/F slab to
be cast
24
Construction sequence – South Podium
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B2 slab to
be cast
STAGE 8:
1. Demolish cofferdam diaphragm wall to
below B2.
2. Construct and connect B2.
3. Remove struts below B2.
B2 slab
previously cast
B2 slab
previously cast
Hack Dwall to
below B2 slab
RL(m)
Retail
110
100
MICE
Hack Dwall to
below B4 slab
STAGE 9:
1. Demolish cofferdam diaphragm wall to
below B4 slab.
2. Complete basement structure.
B4 slab
previously cast
Hack Dwall to
below B4 slab
RL(m)
Retail
110
MICE
100
B2 slab
90
90
Sand
Sand
80
80
70
70
60
60
50
50
40
40
25
Construction sequence – South Podium
26
Construction sequence – South Podium
Koden Test on every panel to check Verticality
Recorder
Koden Test Results
27
View of central 120m donut
28
Winch Unit
Construction of cofferdams
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Steel truss against top of donuts to retain stability of donuts
when excavating outside
Inclinometer readings
Excavation
Steel Truss Layout
A0 (+)
B0 (+)
B180 (-)
A180 (-)
GSA Analysis
29
Construction of cofferdams
30
Design of cofferdams
Steel truss against top of donuts to retain stability of donuts
when excavating outside
30,000 m3
8,000 trucks
31
Design of cofferdams
32
Removal of cofferdams above excavation level
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Oct 2008
33
Sequence for North Podium (a) (Casino – Retail)
34
Semi Top Down Excavation (Casino Area)
South Podium
North Podium
Struts
along
Dwall
8m
17.5m
Steel
Truss
Initial excavation
11m
17.5m
Excavate North
OR
Excavate South
35
Semi Top Down Excavation (Casino Area)
36
3D analysis carried out to investigate stability of north donut
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Museum
Retail
Theatre
RL(m)
100
90
Sand
80
70
60
50
Shear support to museum from the curved wall supported at ends
37
Museum C Wall
38
Museum C Wall
Oct 2008
SAP model of circular
with loads being
transferred in shear to
Old Alluvium at the
ends.
Lateral support at the
ends provided by
anchors on the north
side and adjacent bored
pile perimeter wall at
south hear support to
museum form the
curved wall supported at
the south side.
39
Museum C Wall
40
Excavation at DTE – DCS - Theatre
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DCS
Theatres
200.00
210.00
220.00
230.00
240.00
CT
DTE
250.00
260.00
270.00
280.00
290.00
310.00
320.00
330.00 Bridge
340.00
350.00
Benjamin
Sheares
300.00
Lateral Force from the East of DTE
110.00
movement control
100.00
mm
40.00
84.5
30.00
Continuously Reinforced
20.00
Wall (Shear Wall)
26m
90.00
Lateral Force from East of DTE
BSB
10.00
80.00
00.00
78
-10.00
70.00
-20.00
67
60.00
-30.00
-40.00
50.00
-50.00
-60.00
40.00
-70.00
-80.00
30.00
-90.00
20.00
Horizontal Displacement Contour
-100.00
Large lateral soil load to be carried in shear to the DCS
requires continuously reinforced shear cross walls to
transfer load to Old Alluvium
 DCS box needs to resist large lateral earth pressure from the East of DTE
 DTE movement needs to be controlled to minimise impact onto BSB
41
DTE – DCS – Theatre Area : Issues
42
Continuously reinforced Shear Wall
DTE – DCS – Theatre Area : Issues
Theatres
Extent of trench
for female panels
43
6400
3000
Male panel
(excavated after
adjacent female
panels are
concreted)
Female panel
(only the
middle
portion is
concreted)
DTE – DCS – Theatre Area : Issues
44
Regular review of DCS performance
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Theatres
45
Regular review of DCS performance
46
Regular review of DCS performance
Pier 19
N
Benjamin Sheares Bridge - Elevation
Pier 20
Pier 21
MBS Site
Pier 21
47
Benjamin Sheares Bridge
48
Pier 22
South Abutment
Benjamin Sheares Bridge
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Theatre
DCS
Theatre
TBM
Shaft
DCS
DTE
DTE
Dowell pins
overstressed
Inevitable movement
to the bridge abutment
49
TBM
Shaft
Benjamin Sheares Bridge
50
Benjamin Sheares Bridge
Theatre
Underside of deck
DCS
TBM
Shaft
Deck crossbeam
DTE
Inevitable movement
to the bridge abutment
Allow articulation
between the Pier
and the Deck
Section on Plan
Pier crosshead
View looking up from underneath
51
Benjamin Sheares Bridge
52
BSB Adjustable Shear Pins
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0
Adjustment dates
10
20
30
40
50
mm
53
Adjustment schedule
54
Permanent underslab drainage
The end
55
14