Pres_Proven+Practices+for+Launching+–+Robert+Gale[1]

7/28/2019 Pres_Proven+Practices+for+Launching++Robert+Gale[1]

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Proven Practices for IncrementalLaunching of Steel GirderBridges

2012 CISC Alberta Steel Workshop

By: Robert Gale, PEng



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Presentation Outline

1) Overview of Launching and how can it be used forconstruction of steel structures bridges or other

2) Site Constraints for Launching - Reviewing the suitabilityof the site. Two projects Park Bridge & Coast Meridian

3) Bridge Design for Launching - Adequacy of permanentbridge superstructure for temporary launching demands

4) Fabrication and Assembly for Launching - unique aspects

5) Launch Equipment - Function of systems typically used

6) "Jack Down" after Launching - Transfer of bridgesuperstructure from temporary supports to permanent

bearings7) Summary and Conclusion



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1) Overview of Launching

Architect/Design Engineer

GeneralContractor

r

y

orDesign

Build

Simple Org Chart


ConstructionEngineer or

ErectorFabricator

Construction

Method

Launching?

Many items need to "fallinto place"

ConventionalDelive


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Launching can be used for many types of structures, but alignment

should be straight or constant curve.

Launching is a viable option for regions of: Steep or inaccessible terrainof obstacles below, or heavy vehicle traffic below.

Design girders for permanent loads and temporary launch loads.

ec e emen s o supers ruc ure or aunc ng sp ces, o om ange,plan bracing, jacking stiffeners). May need re-design.

Require an assembly bed that is wide enough for crane access and longenough to assemble girders to safely cantilever out.

Launching may not be cost effective if traditional construction methodsare available (Need to manage all girders throughout work).



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Examples of Some Recent Launching Projects



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Deh Cho Bridge, NWT



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Athabasca Bridge, Fort McMurray, AB


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South Layton Overpass, UT



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Capilano River Bridges, N Vancouver, BC



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1) Overview of LaunchingPeace Bridge, Calgary, AB



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1) Overview of Launching and how can it be used forconstruction of steel structures bridges or other.

2) Site Constraints for Launching - Reviewing the suitabilityof the site. Two projects Park Bridge & Coast Meridian.


4) Fabrication and Assembly for Launching - Unique aspects






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2) Site Constraints

Old Park Bridge

One of the highest rock fall hazard areas in BC.Accident rate double the provincial average.



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2) Site Constraints


Site Layout for New Park Bridge


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2) Site Constraints


Assembly Bed at West Abutment


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2) Site Constraints Launch Video

15WBES 2011 Phoenix, AZ

Courtesy of BC MoT and Focus Corp.


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2) Site Constraints

Assembly Bed


Fabrication

Shop

Coast Meridian Overpass (CMO) Site


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2) Site Constraints



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2) Site Constraints


CMO first launch


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2) Site Constraints


CMO in final position after last launch


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1) Overview of Launching and how can it be used forconstruction of steel structures bridges or other.

2) Site Constraints for Launching - Reviewing the suitabilityof the site. Two projects Park Bridge & Coast Meridian








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3) Bridge Design for Launching

Bridge designed to S-6 with separate launch criteria for loadcases for the temporary launching demands. Mostly have todeal with dead load, wind load, and other effects such astraining (guiding) forces and temperature.

Superstructure designed for permanent load cases and

checked and modified as necessar for launch load cases.Most efficient if these are completed concurrently, as with adesign-build project.

2-D beam models (typical cases) and 3-D FE models(governing longitudinal cases including transverse loads)used to check structure for launching. Careful of cambereffects on the moving structure as can lift off close supports.



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Superstructure:

Girder non-composite bending moment

Bolted field splices

Localized web buckling for cantilever reaction

Transverse Loads wind loads and others Jack Down loads

Piers & Abutments:

Longitudinal and transverse reactions at Pier Equipment

Jack Down loads. Sequence may cause increase loads.



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Example 3-span plate girder bridge for launching



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Typical bridge cross section for permanent bridge



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Governing case for launching



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Launching cross section



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Girders in final position but not on permanent bearings yet



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Jack Down at Piers



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Image provided by Structural Concepts

Span to depth ratio not greater than range of about 20 to 25



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Flush bottom flange to allow girder unobstructed advance on rollers.Constant width of bottom flange easier, but not required, for guiding



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Bolted field splices detailed to allow passage of roller

No coatings in roller path or use weathering steel



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1) Overview of Launching and how can it be used for

construction of steel structures bridges or other.





6) "Jack Down" after Launching - Transfer of bridgesuperstructure from temporary supports to permanentbearings

7) Summary and Conclusion



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4) Fabrication and Assembly


Assemble at "no load" camber so that DL steel deflections are correct after launching


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Launched uphill in two section due to 6% slope



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Detailed for steel dead load in position with oversize holes



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Deliver 1 girder every 3 days



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View of Interior framework and two main rib beams for cable-stay loads.

More than 180,000 bolts for structure



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5) Launch Equipment NoseTemporary lighter girders attached to

leading end of permanent girders.

Sloped up for cantilever deflection

Reduce cantilever overturning moment

Custom design to suit conditions



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5) Launch Equipment Nose

Nose is lighter using truss - but more detailed fabrication required



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Hinged nose to accommodate large cantilever deflection for long spans



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Simple temporary nose using rolled beam sections



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Can accomplish with no nose in the right situation



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5) Launch Equipment On Piers

Nose about to touchdown on rollers



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Close-up of roller nests (green) and guide wheel



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Roller assembly with integral guide system.

Can also side on greased plates or teflon/stainless systems



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Roller assemblies need certain amount of space on pier top for equipment

and temporary anchor bolts



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5) Launch Equipment Moving

Friction system for Park Bridge - hydraulic rams with clamping jaws

All pushing force goes into concrete abutment



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5) Launch Equipment Animation


Courtesy of BC MoT and Focus Corp.


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Friction system for CMOP girder clamp rides on bottom flange



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Winching with

tackle pulling

from abutment

to equalizer

beam at back

end



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Winching by

pull directly

from front



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Launch system using two linked strand jacks pulling from abutment



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Using multiple linked strand jacks on steel rails behind abutment



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6) Jack Down at Piers

1200mm (4-ft) Jack Down with 700 tons load



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Remove temporary rollers


Slide-in permanent bearing



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Bearing in position

Bearing installed



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7) Summary What to Remember

Launching can be used for many types of structures, but should be

straight or constant curve.

Launching is a viable option for regions of: Steep or inaccessible terrainor obstacles below, or heavy vehicle traffic below.

Design girders for permanent loads and temporary launch loads.

ec e emen s o supers ruc ure or aunc ng sp ces, o om ange,plan bracing, jacking stiffeners). May need re-design.

Require an assembly bed that is wide enough for crane access and longenough to assemble girders to safely cantilever out.

Launching may not be cost effective if traditional construction methods

are available (Need to manage all girders throughout work).



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7) Summary - Additional Information

62

Incremental Launching of Steel Girders in British Columbia

Two Case Studies

Structural Engineering International (SEI) magazine,November 2011 Issue



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Acknowledgements

General Contractors

Park Bridge: Flatiron Construction Corp (Richmond, BC)

CMO: SNC Lavalin Constructors Pacific (Vancouver, BC)

Erector

KWH Constructors & Somerset Engineering (Burnaby, BC)

Fabricators

Park Bridge: Rapid-Span (Armstrong, BC)

Park Bridge: Structal-Bridges (Quebec)

CMO: Geo. Third & Son (Burnaby, BC)

CMO: Dynamic Structures (Port Coquitlam, BC)



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Thank-you !!

Questions?


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