3 June 2008 1

Rapid Replacement of the Hood CanalBridge Approach Spans

Joseph Merth, P.E.Bridge Design Engineer

3 June 2008

3 June 2008 2

Overview Introduction Current Project Approach Design Approach Construction Challenges

West Approach

East Approach

Floating Structure

3 June 2008 3

Location

OlympicPeninsula

Seattle

Hood CanalBridge

Puget Sound

3 June 2008 4

Location

Hood CanalBridge

Hoo

d C

anal

3 June 2008 5

3 June 2008 6

Hood CanalBridge

3 June 2008 7

Hood Canal Bridge

3 June 2008 8

West HalfFloatingStructure

East HalfFloatingStructure

DrawSpan

EastApproach

WestApproach

TransitionSpan

TransitionSpan

3 June 2008 9

Bridge Facts

Length – 7869 feet

(Longest floating bridge over salt water) Floating portion – 6530 feet Max water depth – 340 feet Tidal Variation – 16.5 feet Center draw span opening – 600 feet

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Bridge History Original Construction – January 1958 Open to traffic – 12 August 1961

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West Half Fails

February 13, 1979 Sustained winds of 85mph 120mph gusts

3 June 2008 12

West Half Replacement

Reopened Oct. 25th, 1982 Post-tensioned pontoons Increased anchor size

3 June 2008 13

Current Project

Replace Approaches(completed)

Replace Transition Spans

Replace EastHalf Pontoons(6 to 8 wk. closure)

Widen West Half SuperstructureFrom 28’ to 40’ (completed)

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Approaches Provide fixed link from shore to floating structure Help resist longitudinal wind and wave forces from the

floating structure

Wind/WaveForces

FloatingStructure

ApproachSpans

TransitionSpan

TidalMovement

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Original West Approach

2 – span haunched steel PL Girder 190’ length Buttress added for West half

replacement

Buttress

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OriginalEastApproach

6 – span haunched steel PL Girder

643’ length Wind/Wave forces –

Pier 4

Pier 4

3 June 2008 17

Approach Retrofit Original Retrofit Requirement

Deck Replacement Seismic Retrofit Pier 4 retrofit (add buttress wall)

Required 6-8 week closure

West East

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Approach Replacement

Replace entire approaches (superstructure/substructure) Build to current standards – 40’ roadway, seismic Ability to widen to 4 lanes (60’) in the future

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Typical Section

6’ Dia.Column

10’ Dia.Shaft

40’Roadway

PrestressedGirder

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West Approach Elevation

1 span (W83G Girders) 154’ total length

CL Pier 1 CL Pier 2

154’

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East Approach Elevation

609’

CL Pier 5 CL Pier 6 CL Pier 7 CL Pier 8 CL Pier 9

Pier 10

5 spans (W74G Girders) 609’ total length

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Replacement Challenges Limited closure – extended weekend

Construct superstructure adjacent to existing approach

Distribute wind/wave forces into East Approach

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RollingScheme

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Rolling SchemePrior to Rollover

3 June 2008 25

Rolling SchemePrior to Rollover

3 June 2008 26

Rolling SchemePrior to Rollover

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Rolling SchemePrior to Rollover

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Rolling SchemeDuring Rollover

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Rolling SchemeDuring Rollover

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Rolling SchemeDuring Rollover

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Rolling SchemeDuring Rollover

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Rolling SchemeDuring Rollover

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Rolling SchemeAfter Rollover

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Rolling SchemeAfter Rollover

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Rolling SchemeAfter Rollover

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Wind/Wave Forces

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Hinge Diaphragm

3 June 2008 38

Hinge Diaphragm

3 June 2008 39

Hinge Diaphragm

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Hinge Diaphragm

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Hinge Diaphragm

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Hinge Diaphragm

LongitudinalStop

LongitudinalBearing

Bearing

3 June 2008 43

Hilman Roller

Rolling AssemblyA

A

Section A-ARollingPlate

HilmanRoller

Temp.Elast.Brg.

3 June 2008 44

Hilman Rollers

5 spans 800 to 1500 kips DL/Pier 7600 kips Total 2 Hilman rollers/span (300 or 500

ton capacity)

East Approach 1 span 1000 kip DL/Pier 2000 kips Total 2 Hilman rollers/span (300

ton capacity)

West Approach

3 June 2008 45

Construction

3 June 2008 46

Work Trestle

Trestle and Falsework scheme included in Contract

Contractor required to submit for review and approval

Falsework system designed for ½ seismic acceleration (0.15g)

M OVE EXIS T . S UP ERS T RUCT URE A ND S LIDENEW S UP ERS TRUCTURE INT O P LA CE .

¢ S R 10 4

¢ COLUMN & S HA F T ¢ COLUMN & S HA F T

20 '-10 ½" 20 '-10 ½"

S TAGE 4

13 .5 High Wat er

M .L.L.W. E l. 0 .0

R/ W line

R/ W LineP ile Cap S ect ion

2' Diam. S t eel P ileS t eel G irder s

T imber Deck P lanks

Temporary S t eelCrossbeamExt ens ion

Temp. s t eel P iles

Exis t ing S upers t ruct ure t o be removed

Exis t ing P ier t o beremoved

New S upers t ruct ure

New Crossbeam

New S upers t ruct ure cons t ruct edon Crossbeam Ext ens ion

10 ' ø Dr illed S haf t

New 6 ' ø Column

Exis t ing CanalBot t om

Temporary Concret eCrossbeam Ext ens ion

Temporary CrossbeamS uppor t s

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Work Trestle 58,000 ft2

260 – 2’ Diameter Piles 4 months to construct

East Approach

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Substructure 12 – 10’ Diameter Shafts 5 ½ Months Construction Epoxy Coated Rebar –

Entire Structure

East Approach

3 June 2008 49

Superstructure

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Hydraulic Jacking – Horizontal West Approach – 2 synchronized jacks East Approach – 6 synchronized jacks Max horizontal force/jack – 30 to 80 kips Max ¼” differential horizontal movement between adjacent

piers during rolling

New Bridge -Original Position

New Bridge -After Rollover

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Hydraulic Jacking – Horizontal

RollingPlate

JackingRod

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The Rollover

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Hydraulic Jacking – Vertical

3 June 2008 54

Hydraulic Jacking – Vertical

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Hydraulic Jacking – Vertical

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Hydraulic Jacking – Vertical

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Hydraulic Jacking – Vertical

RollingPlate

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Hydraulic Jacking – Vertical Jacking performed pier by pier 10 synchronized jacks interior piers, 5 at end piers Max relative differential movement between jacks = ¼” Max relative differential movement between piers = 2” Pressure system used for vertical jacking

3 June 2008 59

East Approach Aerial Photos

Before During After

3 June 2008 60

Approach Closure Schedule

West Approach

Thursday(11 Aug 05)

Friday(12 Aug 05)

Saturday(13 Aug 05)

8:00PMClose Bridge

4:00AMExist. Bridge Rolled

6:00PMNew Bridge Rolled

10:20PMBridge Openedto Traffic

East Approach

Sunday(21 Aug 05)

Monday(22 Aug 05)

Tuesday(23 Aug 05)

8:00PMClose Bridge

4:00PMExist. Bridge Rolled

12:00AMNew Bridge Rolled

8:40PMBridge Opened to Traffic

51 hrs 49 hrs

3 June 2008 61

Closure Challenges

3 June 2008 62

Abutment and Approach Slabs

Precast Abutment Endwall Precast Approach Slabs

3 June 2008 63

Abutments

3 June 2008 64

Abutments

Crossbeam

3 June 2008 65

Abutments

Cast-in-placeEndwall

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Abutments

3 June 2008 67

Abutments

PrecastEndwall

3 June 2008 68

Abutments

3 June 2008 69

PrecastApproachSlab

Abutments

3 June 2008 70

Precast Abutment Endwall Construction

Cast-in-Place Endwall Precast Endwall

Cast-in-placeEndwall

Precast Endwall

3 June 2008 71

Precast Abutment Endwall Construction

PrecastBackwall Backfill

Voids

3 June 2008 72

Precast Approach Slab

6 Sections 25’ x 8’ x 1’-1”

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ExpansionJoints

3 June 2008 74

750 kips 750 kips

Lessons LearnedUnequal Bearing Loads

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Lessons LearnedUnequal Bearing Loads

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Lessons LearnedUnequal Bearing Loads

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Lessons LearnedUnequal Bearing Loads

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Lessons LearnedUnequal Bearing Loads

300 kips/bearing Design Load.

3 June 2008 79

Lessons LearnedUnequal Bearing Loads

3 June 2008 80

Lessons Learned Unequal Bearing Loads Jacking and shimming required

Prior to Shimming

After Shimming

Design DL = 300 kipsEstimated DL = 500 kips

3 June 2008 81