construction of the cable- stayed...

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Second International Seminar on the Design & Construction of the SECOND PENANG BRIDGE

CONSTRUCTION OF THE CABLE-STAYED BRIDGE

Dr. Robin Sham, Global Long Span and Specialty Bridges Director, AECOM

Dr. Frank Fan, Associate, AECOM

Mr. Liu Yu Feng, Project Chief Engineer, Section 4, CHEC

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Second Penang Bridge – in situ concrete cable-stayed

bridge

January 29, 2013 Presentation Title

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Introduction

AECOM is consultant to China Harbour Engineering Consultant (CHEC) in Second Penang Bridge • design, • specialist advice • construction supervision and • construction engineering. In the construction of the cable-stayed bridge, AECOM is responsible for construction engineering, including erection analysis, geometry control and temporary work design.

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CONSTRUCTION ENGINEERING

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Construction Engineering

Three Main Objectives: 1.To establish a methodology for the construction of the bridge which does not cause overstress to any part of the permanent bridge structure during construction

2.To safeguard structural adequacy, integrity and stability throughout the erection stages including bridge completion

3.To achieve the reference states of the permanent works, including the permanent load geometry and force distribution defined by the Design

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General Arrangement

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The Target Bridge Geometry

Target bridge geometry is determined for

the Reference Condition

1)under permanent loads only,

2)at a reference temperature of 30OC

3)at the time of 30 years after bridge completion

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The Target Bridge Geometry

Deck Segment Control Points

1) Edge Beam: H2

2) Slab: (H1 - 30mm thick asphalt)

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Stay Cable Force Distribution

The target stay cable forces at bridge completion

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Stress Limits during Construction – BS5400

Prestressed concrete members

• Tensile Stress Limit = 1 MPa

• Compressive Stress Limit = 0.4 Fcu

• ULS – PM Interaction

Reinforced concrete members

• No stress limits for serviceability limit state

• DESIGN BRIEF, Revision 3, May 2010 specifies

Crack Width Limit =0.20 mm

• ULS - PM Interaction

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Construction Manual provides the following data

1) Geometry Control Measures necessary for bridge construction

2) Pylon Setting-Out – Coordinates of Control Points

3) Deck Setting-out (edge beams and deck slabs) - Coordinates of Control Points

4) Stay Cables Setting-Out – Coordinates of Control Points, cable lengths, sags, initial and staged stay cable forces

5) Deck profiles at Various Stages – Bridge Completion, 30 Years after Bridge Completion and 120 Years after Bridge Completion

6) Stay Cable Forces at Various Stages – Bridge Completion, 30 Years after Bridge Completion and 120 Years after Bridge Completion

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LOADS considered in Construction Analysis

1) Construction Loads – including self-weight, equipments, form traveller, etc

2) Wind Loads

• Construction mean hourly wind speed = 25.175 m/s

• Static wind forces – drag, lift and moment

• Wind buffeting effects (time history simulation)

3) Thermal Loads

• uniform temperature 30°C ± 10°C

• Differential temperature through depth and across width of deck girder (ULS only)

• Differential T between deck girder and stay cables (ULS only)

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Construction Loads

1) Form traveller and formwork on each side = 1655 kN

2) Construction equipment load = 50 kN at the tip of cantilever (cantilever stressing platform)

3) Unbalanced a half segment weight = 1800 kN

4) Differential construction live loads = 5 kN/m on one side of cantilever

5) Differential dead load = one side of cantilever is heavier by 5%

6) Unbalanced weight due to loss of one form traveller = 1655 kN while form traveller moves forwards

7) Other miscellaneous construction loads

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Load Combinations

Combination Load

Factor SW EL WL TGL

Unbalanced Loads

Half Deck

Segment

Diff. Dead

Load

Diff. Const

Live Load Diff. WL

Loss of

Form

Traveller

SLS (1)

1.0 1.0 1.0 1.0

(2) 1.0 1.0 1.0 1.0 1.0 1.0

ULS

(1)

1.1

1.15 1.15 1.1

(2) 1.15 1.15 1.0 1.0 1.0 1.0

(3) 1.15 1.15 1.0 1.0 1.0 1.0

(4) 1.15 1.15 0.55 1.0

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MATERIAL PROPERTIES

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Material Properties – Cube Compressive Strength, fcu

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Material Properties – Elastic Modulus, Ec

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Material Properties – Splitting Tensile Strength, fct

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CONSTRUCTION TOLERANCE

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Construction Tolerance - Specifications Section 22: In

Situ Segmental Construction

Deck Profile

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Construction Tolerance

Pylon Profile

Stay Cable Forces within 5%

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CONSTRUCTION METHOD AND

SEQUENCE

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Construction Sequence Construction Drawing P2B/P1/VOL2-2/3001

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Construction Sequence

1) Transition Piers and Pylons P024, P025, P026, P027

2) Deck Segments 0 and 1 on falsework

3) Deck Segments 2 through 16 by Form Traveller (12-day

cycles)

4) Deck Segments SS18, SS17 – side span closure

5) Deck Segments MS17, MS18

6) Deck Segment MS19 – main span closure

7) Last tensioning of stay cables

8) Adjustment of stay cable forces as necessary

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Form traveller for cable-stayed bridge erection


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Typical Construction Cycle of One Deck Segment – 12 days

On the 1st Day

1) Cast the edge beams of Deck Segments N (N = 02 to 16).

On the 6th Day:

2) Stress the cantilever tendons in the edge beams of Deck Segments N upon the concrete reaching 47MPa.

3) Stress the transverse tendons N1, N3 in the diaphragms of Deck Segment N-1.

4) Stress the transverse tendons N2 in the diaphragms of Deck Segment N-2.

Schematic Elevation of Form Traveller

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On the 7th Day:

5) Apply the first tensioning of Stay Cables MN and SN on Deck Segment N simultaneously.

1st

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On the 8th Day

6) Fold down all the formworks (including edge beams, slabs and diaphragms)

7) Connect launching system to the front bogies and the launching rails.

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On the 8th Day

8) Launch the rail to Deck Segments N.

9) Lower down the form traveller and remove the high tension bars.

10)Launch the form traveller to Deck Segments N.

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On the 9th Day:

11)Lift up the form traveller and install the high tension bars.

12)Fold up the formworks and install rebar cages (slabs and diaphragms).

13)Apply the second tensioning of Stay Cables MN and SN simultaneously.

On the 10th Day:

14)Cast the slabs and diaphragms of Deck Segments N on both main and side spans simultaneously.

2nd

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On the 12th Day, for N = 02 to 15:

15)Apply the third tensioning of Stay Cables MN and SN simultaneously.

16)Fold up the formworks and install rebar cages (edge beams).

On the 15th Day, for N = 16

17)Stress the transverse tendons N1, N3 in the diaphragms of Deck Segment SS16.

18)Stress the transverse tendons N2 in the diaphragms of Deck Segment SS15.

19)Stress the transverse tendons N2 in the diaphragms of Deck Segment SS16.

3rd

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Deck Segments SS18 and SS17 (side span closure)

SS17 – Side Span Closure

Current Design for Temporary Support

SS17 – Side Span Closure

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Deck Segment MS17 – 12 days


MS18 Edge Beams

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MS18 East - Slab and Diaphragm

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MS18 West - Slab and Diaphragm

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Deck Segment MS19, Main Span Closure – 7 days

MS19 – Main Span Closure

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Main Span Closure

1. Position cantilever tips at the same level

2. Install counter-weights and

3. Jacking cantilever tips toward pylons

4. Install strongbacks

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Stage-by-Stage Construction

C:/Users/Ashraf/Desktop/Presentation/2ISDC (robin's presentation)/P2B_Construction Sequence 1sec interval.pptx

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CONSTRUCTION OF PYLONS

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Pylon Construction: Pre-camber and Setting-Out

Pre-camber values are given as the coordinates in the global coordinate system:

X – Longitudinal pre-camber of the pylon (Chainage)

Y – Transverse pre-camber of the pylon (Center line of the bridge = 0.000, North is positive, South is negative)

Z – Vertical pre-camber of the pylon (Elevation based upon Malaysia NGVD)

The pylons are cast to pre-cambered profile:

1) Leaning towards the transition piers for longitudinal (X) pre-camber

2) Leaning inwards, towards the bridge centerline for transverse (Y) pre-camber

3) Higher than the theoretical elevation for vertical (Z) pre-camber

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Control Points for Pylon Segment

CL PYLON AND CONTROL POINTS CL PYLON AND CONTROL POINTS

ELEVATION VIEW A-A ELEVATION VIEW B-B

E E

D D

SECTION E-E

SECTION D-D

CL OF BRIDGE

PILECAP TOP LEVEL

MAIN SPAN SIDE SPAN

CONTROL POINT 01

EL=2.680

CONTROL POINT 02

CONTROL POINT 03

EL=8.320

CONTROL POINT 04

EL=12.820

CONTROL POINT 05

CONTROL POINT 06

CONTROL POINT 07

EL=17.320

EL=21.820

EL=26.320

CONTROL POINT 08

CONTROL POINT 09

EL=39.820

CONTROL POINT 10

EL=44.320

CONTROL POINT 11

EL=48.820

CONTROL POINT 12

EL=53.320

CONTROL POINT 13

EL=57.820

CONTROL POINT 14

EL=62.320

CONTROL POINT 15

EL=66.820

CONTROL POINT 16

EL=71.320

CONTROL POINT 17

EL=75.820

CONTROL POINT 18

EL=80.320

CONTROL POINT 19

EL=84.820

CONTROL POINT 20

EL=89.320

CONTROL POINT 21

EL=93.820

EL=30.820

EL=35.320

CONTROL POINT 22

EL=96.280

CONTROL POINT

CONTROL POINT

• 24 Segments Per Pylon • 2 Control Points for Each Segment Pour, One at Each End Face

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Pre-camber at Control Points of Pylon P25S

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Stress Envelopes for Pylon P025N

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Pylon Construction

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Transition Pier 027

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Pylon 026

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Cable Saddle

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CONSTRUCTION OF DECK

SEGMENTS

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Deck Segment Construction: Pre-camber and Setting-Out

For setting-out of edge beams, the control points along the fascia lines of the deck segments are used. The coordinates of the control points incorporating pre-camber are expressed as:

1) X = Chainage at ends of edge beam segments + ΔX pre-

camber

2) Y = +/- 17,300mm + ΔY pre-camber

3) Z = Elevation H2 + ΔZ pre-camber

Note: The “Z” coordinate at Control Point H2 has to include an additional deformation of form traveller under the self-weight of edge beams. The data is provided by the construction team.

1. Edge Beams

Deck segment pour in two stages: edge beam pour followed by diaphragm and slab pour

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Pre-camber – Edge Beams at Control Point H2

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Edge Beams Profile at Various Stages

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Stress Envelope – Edge Beams

• Tensile Stress Limit = 1 MPa • Compressive Stress Limit = 0.4 Fcu = 0.4 (55) = 22 MPa

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For setting-out of slab and diaphragm, control points along the center line of the deck are used. The coordinates of the control points are:

1) X = Chainage at ends of slab segments + ΔX pre-camber

2) Y = 0 mm + ΔY pre-camber

3) Z = Elevation H1 – 30mm asphalt thickness + ΔZ pre-camber

Note: The “Z” coordinate at Control Point (H1-30mm) has to include an additional deformation of formwork under the self-weight of deck slab. The data is provided by the construction team.

Deck Segment Construction: Pre-camber and Setting-Out

2. Slabs

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Pre-camber – Slabs at Control Point (H1-30mm)

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Slab Profiles at Various Stages

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Stress Envelope – Slabs

• No stress limit under SLS. • Crack Width limit = 0.20 mm (Design Brief)

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Form Traveller

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Tie-arch concept in form traveller design and fabrication


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Deck Segments 0 and 1

erection on falsework

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Typical deck segment

erection with form

traveller

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INSTALLATION OF STAY CABLES

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Stay Cables Construction

TLA1

TP1 TP2

TLA2

Control Points –

• Deck Anchorage: TLA1, TLA2

• Pylon Saddle: TP1, TP2

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Stay Cables Installation

Control Point Coordinates for Northwest Side Span

X— Chainage

Y— Transverse Direction (North Positive; South Negative)

Z— Elevation (Relative To Malaysia NGVD)

Chord

Length

Chord

Length

Elongation

∆L

Unstrained

Length

Lu

Total

Length

L = ∆L + Lu

Sag

X(m) Y(m) Z(m) X(m) Y(m) Z(m) (m) X'(m) Y'(m) Z'(m) X'(m) Y'(m) Z'(m) (m) (m) (m) (m) (m)

S01 1965.417 16.500 31.516 1979.338 16.500 48.422 21.899 1965.417 16.500 31.512 1979.337 16.498 48.420 21.901 0.044 21.857 21.901 0.014

S02 1959.414 16.499 31.411 1979.327 16.497 52.186 28.777 1959.413 16.500 31.419 1979.327 16.497 52.186 28.772 0.026 28.747 28.773 0.055

S03 1953.411 16.499 31.309 1979.321 16.497 54.892 35.036 1953.409 16.500 31.324 1979.321 16.497 54.892 35.027 0.033 34.994 35.027 0.076

S04 1947.408 16.499 31.203 1979.316 16.496 57.524 41.363 1947.405 16.500 31.227 1979.316 16.496 57.524 41.350 0.036 41.315 41.351 0.117

S05 1941.405 16.499 31.094 1979.311 16.496 60.116 47.740 1941.402 16.500 31.127 1979.311 16.496 60.116 47.722 0.043 47.680 47.723 0.149

S06 1935.403 16.499 30.979 1979.307 16.496 62.683 54.154 1935.400 16.500 31.022 1979.307 16.496 62.683 54.132 0.051 54.082 54.133 0.184

S07 1929.402 16.499 30.859 1979.303 16.495 65.235 60.596 1929.398 16.500 30.911 1979.303 16.495 65.235 60.570 0.059 60.513 60.571 0.223

S08 1923.401 16.499 30.726 1979.299 16.495 67.776 67.061 1923.396 16.500 30.788 1979.299 16.495 67.776 67.031 0.052 66.982 67.035 0.341

S09 1917.400 16.499 30.592 1979.296 16.495 70.309 73.542 1917.395 16.500 30.660 1979.296 16.495 70.309 73.510 0.058 73.456 73.514 0.401

S10 1911.399 16.499 30.452 1979.293 16.494 72.836 80.037 1911.393 16.500 30.526 1979.293 16.494 72.836 80.003 0.065 79.943 80.008 0.464

S11 1905.397 16.499 30.307 1979.289 16.494 75.359 86.543 1905.391 16.500 30.387 1979.289 16.494 75.359 86.507 0.072 86.442 86.513 0.533

S12 1899.397 16.499 30.157 1979.287 16.494 77.877 93.057 1899.390 16.500 30.244 1979.287 16.494 77.877 93.019 0.078 92.948 93.027 0.606

S13 1893.396 16.499 30.005 1979.284 16.493 80.394 99.579 1893.388 16.500 30.098 1979.284 16.493 80.394 99.537 0.085 99.462 99.547 0.685

S14 1887.393 16.499 29.866 1979.280 16.493 82.907 106.096 1887.385 16.500 29.967 1979.279 16.493 82.907 106.053 0.091 105.972 106.064 0.768

S15 1881.391 16.499 29.731 1979.275 16.492 85.419 112.616 1881.382 16.500 29.841 1979.275 16.492 85.419 112.569 0.101 112.481 112.582 0.833

S16 1875.389 16.499 29.599 1979.269 16.492 87.929 119.137 1875.379 16.500 29.720 1979.269 16.492 87.929 119.086 0.104 118.997 119.101 0.953

S17 1871.402 16.500 29.724 1979.392 16.491 90.427 123.881 1871.392 16.500 29.714 1979.326 16.491 90.425 123.837 0.097 123.761 123.858 1.149

S18 1867.407 16.500 29.637 1979.401 16.491 92.921 128.638 1867.398 16.500 29.632 1979.339 16.491 92.919 128.593 0.108 128.506 128.614 1.156

Control Point TLA1-Deck Control Point TP1-Pylon Control Point TLA1'-Deck Control Point TP1'-Pylon

Northwest Side Span - Prior To Tensioning of Stay Cables Northwest Side Span - After Tensioning of Stay Cables

Stay No

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Stay Cable Forces Comparison at Bridge Completion

< 5%, OK

Stay No. Resulting Cable Forces (kN) Design Cable Forces (kN) Differences= (Result-

Design)/Design (kN)

S18 5379 5397 -0.3%

S17 3540 3539 0.0%

S16 3781 3791 -0.3%

S15 4091 4111 -0.5%

S14 4205 4226 -0.5%

S13 4322 4339 -0.4%

S12 4254 4271 -0.4%

S11 4342 4363 -0.5%

S10 4386 4411 -0.6%

S09 4425 4455 -0.7%

S08 4473 4511 -0.8%

S07 4613 4657 -0.9%

S06 5190 5235 -0.9%

S05 5471 5512 -0.7%

S04 5756 5785 -0.5%

S03 5670 5580 1.6%

S02 6037 6043 -0.1%

S01 6108 6115 -0.1%

M01 4984 5065 -1.6%

M02 3482 3496 -0.4%

M03 3772 3786 -0.4%

M04 4143 4157 -0.3%

M05 4328 4336 -0.2%

M06 4444 4445 0.0%

M07 4346 4343 0.1%

M08 4464 4457 0.2%

M09 4510 4503 0.2%

M10 4495 4493 0.0%

M11 4916 4917 0.0%

M12 4983 4986 -0.1%

M13 5055 5059 -0.1%

M14 5232 5238 -0.1%

M15 5201 5210 -0.2%

M16 5463 5478 -0.3%

M17 5868 5895 -0.5%

M18 5901 5938 -0.6%

Total 171633 172143 -0.3%

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On-Site Stay Cable Installation

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SITE SURVEY PROCEDURE

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Site Survey Procedure

Setting-out is based on bridge profiles (deck and pylons) as modified by the pre-cambers provided in the Construction Manual. However, adjustments will be necessary for:

1) site temperature is different

2) construction loadings are not the same as the loads planned

3) correction for any deviations from theoretical profiles from earlier

construction stages

4) foundation settlement

5) falsework deflection and settlement

The survey procedures include generally:

1) pre-pour survey and setting-out

2) post-pour survey

and require geometry, temperature, wind direction and speed, weather condition and construction load mapping surveys.

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REFERENCE POINT

REFERENCE POINT Control Point

Pylon Survey

Pre-Pour Survey

CHEC to measure site temperature, wind direction/speed

AECOM to provide setting-out information at Control Points

Post-Pour Survey

CHEC to measure site temperature, wind direction/speed, pylon concrete temperature, control point coordinates, foundation settlement

AECOM to establish pylon alignment at Control Points, to update/adjust finite element model as needed

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Deck Segment Survey

Pre-Pour Survey

CHEC to measure site temperature, wind direction/speed, construction load map

AECOM to provide setting-out information at Control Points (coordinates and/or break angles)

Post-Pour Survey

CHEC to measure site temperature, wind direction/speed, deck concrete temperature, control point coordinates

AECOM to establish deck alignment at Control Points (H1-30mm) for slabs and H2 for edge beams, to update/adjust the finite element model as needed

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Stay Cable Survey

Pre-Tensioning Survey

CHEC to measure site temperature, wind direction/speed, construction load map

AECOM to provide setting-out information at Control Points - saddles (TP1, TP2) and bearing plates (TLA1, TLA2)

Post-Tensioning Survey

CHEC to measure site temperature, wind direction/speed, stay cable temperature, as-built stay cable forces, Provide lift-off forces as requested

AECOM to establish stay cable force distribution, to update/adjust the finite element model as needed

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Survey Methods

• 3D coordinates measured by Total Station, GPS, or other equipments with precision to a few “mm”

• 3D coordinates shall be converted to the global coordinates system

• The survey results are checked by construction team before transferring to construction engineering team on the same day

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Wind Monitoring

Typical Locations of Anemometers on Pylons

• Stationary and Moveable

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Temperature Monitoring

• Pylon

2.680

30.320

35.320

96.280

95.280

35.320

900900 900900

1

32.64

12001200

CL OF BRIDGE

PILECAP TOP LEVEL

2.5%2.5%

1000

93600

150 KICKER

150 KICKER

ELEVATION VIEW

1

2

3

4

5

6

8

9

10

11

12

13

14

15

16

17

18

19

20

21

7

22

2000

2000

2000

400 2200~4200 400

3000~5000

6000

1

32.64

1000

2000

1000

4000

400 2200 400

3000

SECTION D-D

Tower Crane

EE

D D

One temperature sensor on each face at every three segments

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• Deck

• Stay Cables

Temperature Sensors

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Foundation Settlement

Total Station or GPS Sensors on Pile Caps

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THANK YOU

construction of the cable- stayed...

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