Presentors: Tom Hardinger – Wisconsin DOT Eugene Hietpas – Collins Engineers Inc. This...

Bridge Scour Prevention

Presentors:

Tom Hardinger – Wisconsin DOT

Eugene Hietpas – Collins Engineers Inc.

This presentation and its contents may not be duplicated or reproduced without the expressed written consent of Collins Engineers, Inc.

NC Region Various Structures – Structures B-37-0187, B-71-0018, B-49-0090

Background Information

Design Phase Construction Phase As-Builts

Background Information

Project included 3 bridges over Wisconsin River (Marathon, Portage and Wood Counties in central Wisconsin).

Substructure units are conventional seal, footing and pier walls.

Major flood events 2008, 2010 and 2011.

Post-flood dive inspections revealed major scour issues with streambed and/or substructure undermining.

Project initiated in 2011 and built in late 2012.

B-37-187, STH 34, KnowltonBuilt 1969.Multi-span steel

girder spans.20-38’ water depth.8-10’ streambed

degradation during 2008 flood exposed seal-to-rock interface. Mitigated piers 2 and 3.

B-49-90, CTH HH, Stevens PointBuilt 1999.Multi-span pre-

stressed girder spans.

8-15’ water depth.Pier 4 Seal

undermining at upstream nose.

B-49-90 Existing Condition

B-71-18, STH 73, NekoosaBuilt 1962.Multi-span steel

girder spans.15-22’ water

depth.Localized scour at

piers 2 thru 6.

Design Considerations

• Permanent vs. Temporary Repairs.

• Alternatives.

• Conventional Riprap placement.

• Articulated grout mats/grout bags and structural grout.

• Traffic disruptions.

• Environmental.

• Project Inspection - Most work underwater.

Design Challenges

• Limited WDOT history/experience (design and construction).

• HEC 23 guidelines.

• Input from other states: Montana, Iowa, MN.

• Input from industry.

• Environmental.

• Aquatic bed impacts.

• Development of Specifications.

Project Detail of Scour Repairs

Project 1009-45-65

• Designed by NCR and BOS.

• Let August 14, 2012.

• Cost $532,111.

• Scour Repair Grout: $4,829/CY (6 CY).

• Grout Bags: $482/CY (402 CY).

• 4 “ Grout Mats: $837/CY (256 CY).

• Contractor: JF Brennan Company, La Crosse.

NC Region Various Structures – Structures B-37-0187, B-71-0018, B-49-0090• Construction

• 3D Imaging• Design Phase/Pre-construction• As-Builts

The Challenge

• Can You See Me Now?

Installation/Layout• Issues

As-Builts

As-Builts

As-Builts

QuestionsContact:

Eugene Hietpas

ehietpas@collinsengr.com

Tom Hardinger

Thomas.hardinger@dot.wi.gov