Broadway Street Viaduct Improvement, Broadway Street Viaduct Improvement, Pre-Load Testing and Geotech Report Pre-Load Testing and Geotech Report

WorkshopWorkshop

Consultant PresentationIowa DOT

2nd April 2007

Workshop GoalsWorkshop Goals Agree on recommended bridge and Agree on recommended bridge and

foundation alternative to be carried foundation alternative to be carried forward into preliminary design.forward into preliminary design.

Decide if bridge and geotechnical reports Decide if bridge and geotechnical reports will be combined into one final report.will be combined into one final report.

Discuss level of effort anticipated in Discuss level of effort anticipated in conducting the pre-final design load conducting the pre-final design load testing program for the post-grouted testing program for the post-grouted drilled shafts drilled shafts

Information from February 2006 PIMInformation from February 2006 PIM

Overview of Bridge Replacement OptionsOverview of Bridge Replacement Options

Update to bridge options and schedules Update to bridge options and schedules presented in the June 2006 Draft Bridge presented in the June 2006 Draft Bridge ReportReport

Three bridge replacement optionsThree bridge replacement options

Three bridge lengthening alternativesThree bridge lengthening alternatives

Drilled shafts as foundationsDrilled shafts as foundations

Bridge Construction CostsBridge Construction Costs

Summary of OptionsSummary of Options

OptionOption Estimated Estimated Construction Cost Construction Cost

Estimated Time Estimated Time For CompletionFor Completion

1. Least Cost1. Least Cost $ 10.1 million$ 10.1 million 10 months10 months

2. Shortest 2. Shortest ScheduleSchedule $ 16.5 million$ 16.5 million 7 months7 months

3. Hybrid3. Hybrid $ 10.2 million$ 10.2 million 9 months9 months

Costs do not include approach slabs, demolition and mobilization.Costs do not include approach slabs, demolition and mobilization.

Option 1: Least CostOption 1: Least Cost

Option 1: Least CostOption 1: Least Cost

Option 2: Shortest ScheduleOption 2: Shortest Schedule

Option 2: Shortest ScheduleOption 2: Shortest Schedule

Option 3: Hybrid ConceptOption 3: Hybrid Concept

Option 3: Hybrid ConceptOption 3: Hybrid Concept

Lengthening the BridgeLengthening the Bridge

Construction Cost ImplicationsConstruction Cost Implications

Soil Remediation and Retaining Wall Soil Remediation and Retaining Wall ImplicationsImplications

Lengthening OptionsLengthening Options

Lengthening the BridgeLengthening the Bridge

Lengthening the BridgeLengthening the Bridge Alternate 1Alternate 1

Extend bridge 37’-6” at east endExtend bridge 37’-6” at east end Extend bridge 25’-0” at west endExtend bridge 25’-0” at west end Sloping ground under bridgeSloping ground under bridge MSE walls along sidesMSE walls along sides

Alternate 2Alternate 2 Extend bridge 100’-0” at east endExtend bridge 100’-0” at east end Provides 9’-0” min. vertical clearance under bridgeProvides 9’-0” min. vertical clearance under bridge MSE walls in front of abutmentsMSE walls in front of abutments

Alternate 3Alternate 3 Extend bridge 200’-0” at west endExtend bridge 200’-0” at west end Extend bridge 250’-0” at east endExtend bridge 250’-0” at east end Provides 2’-0” min. vertical clearance under bridgeProvides 2’-0” min. vertical clearance under bridge Soil remediation significantly reducedSoil remediation significantly reduced Cantilevered retaining wall likely used for remaining Cantilevered retaining wall likely used for remaining

short fill heightsshort fill heights

Lengthening the BridgeLengthening the Bridge

Lengthening the BridgeLengthening the Bridge

Alternate 1Alternate 1 Alternate 2Alternate 2 Alternate 3Alternate 3

BridgeBridge $ 500,000$ 500,000 $ 800,000$ 800,000 $ 3,600,000$ 3,600,000

Slope PavingSlope Paving $ 45,000$ 45,000 $ 0$ 0 $ 0$ 0

MSE WallMSE Wall ($ 170,000)($ 170,000) ($ 117,000)($ 117,000) ($ 1,000,000)($ 1,000,000)

Soil Soil RemediationRemediation ($ 40,000)($ 40,000) ($ 75,000)($ 75,000) ($ 600,000)($ 600,000)

Pavement & Pavement & BarrierBarrier ($ 47,000)($ 47,000) ($ 75,000)($ 75,000) ($ 334,000)($ 334,000)

Net CostNet Cost $ 288,000$ 288,000 $ 533,000$ 533,000 $ 1,666,000$ 1,666,000

Average Net Cost for Additional Bridge Length = $ 4,600 / ft.Average Net Cost for Additional Bridge Length = $ 4,600 / ft.

Foundation and Soil Remediation Foundation and Soil Remediation OptionsOptions

Post-grouted Drilled ShaftsPost-grouted Drilled Shafts

Drilled Shafts Socketed in BedrockDrilled Shafts Socketed in Bedrock

CMC Ground Improvements at Bridge CMC Ground Improvements at Bridge ApproachesApproaches

Lightweight Foamed Concrete Fill at Lightweight Foamed Concrete Fill at ApproachesApproaches

Drilled Shaft Load Test Program Drilled Shaft Load Test Program

Expected ScheduleExpected Schedule

Level of Effort Required from Level of Effort Required from CH2M HILLCH2M HILL

Bridge AestheticsBridge Aesthetics

Piers, Abutments, Retaining WallsPiers, Abutments, Retaining Walls

Bridge Railings, Barriers, BeamsBridge Railings, Barriers, Beams

Coloring textures, RusticationsColoring textures, Rustications

LightingLighting