Wadhams Road Bridge Replacement Bridging over a Moving...

Wadhams Road Bridge ReplacementBridging over a Moving Site

Doug Parmerlee, PEAECOM Department Manager, Bridge Design, Michigan

Jane Abadir, PE, LEED® A.P.Somat Engineering, Inc. Project Manager

March 17, 2015

PURPOSE OF TODAY’S PRESENTATION

1) Highlight a complicated and interesting project

2) Highlight the teamwork between the bridge engineers and the geotechnical engineers.

March 17, 2015

PROJECT BACKGROUND

• Owner is St. Clair County Road Commission (Mike Clark).

• Location is approximately 5 miles west of Port Huron.

• Only crossing within a 14 mile stretch of the Black River.

• Total bridge replacement.

• Bid through MDOT Local Agency Programs (Chris Tennes-MDOT Bridge Staff Engineer).

• MDOT Geotechnical Review (Dick Endres).March 17, 2015Wadhams Road Bridge

DESIGN TEAM AND SCOPE

• URS Corporation (AECOM)– Bridge design

– Roadway design

– Traffic engineering

– Signal design

– Pavement markings

– Signing

• Somat Engineering, Inc.– Geotechnical engineering

• Taiga Engineering, LLC– Hydraulic analysis

– Scour analysis

• SCCRC– Survey

– Project Funding

• MDOT– Project oversight

– Geotechnical review

March 17, 2015Wadhams Road Bridge

WHY WAS THIS PROJECT DIFFERENT?

• During a typical project:– Much of the bridge geometry and design is determined without

geotechnical input.– Geotechnical engineers usually help determine foundation type

and/or depth of deep foundations,

• During this project the geotechnical aspects directly or indirectly influenced:– Number of spans– Span lengths– Pier design– Abutment design– Bearing type– Staging


TEAM WORK

• URS and Somat worked together in partnership team rather than as a typical Prime/Sub relationship

• URS and Somat were in daily communication during the life of the project.

• Aspects of the design were iterative and required back and forth between URS and Somat.


PREVIOUS BRIDGES


1st Bridge before 1914 2nd Bridge 1914-1939

3rd Bridge 1939 to date

Adapted from HistoricBridges.org

SOMAT GEOTECHNICAL INVESTIGATION

• Review of historic documents including existing geotechnical data, subsurface studies, involvement of the Prof. Bill Housel (U of M)

• Site visit to inspect bridge distress and observe evidence and extent of slope instability

• Comprehensive Subsurface Geotechnical Investigation• Groundwater monitoring wells• Drained Tri-axial and Direct Shear testing• Developed a soil profile model• Sensitivity analysis for global stability of the south slope.


FIELD INVESTIGATION


EXISTING BRIDGE


SOIL PROFILE


INITIAL BRAINSTORMING

• The sensitivity analysis defined the problem which the slope instability that would result in horizontal pressure applied to the foundations.

• URS and Somat discussed numerous foundation options in-person and via telephone.

• Strut from pier to north abutment

• Soil/cement mixing• Over-excavating and

backfilling with EPS• Retaining wall• Bentonite debonding of

adjacent slopes• “Rocking” Pier• Soil nails• Drilled Shafts• Heavy-Duty integral

abutments


INITIAL BRAINSTORMING

• URS, Somat, SCCRC met with MDOT to discuss initial ideas and results of geotechnical investigation.

• It was decided that the slope instability would cause earth pressures equal to 9 times cohesion (9c).

• The 9c pressures were approximately 10 to 15 times greater than active earth pressure.

• The immense pressures eliminated any attempt to retain/restrain the soil due to economics.

• Immense pressures = substantial foundation elements


DESIGN DECISIONS

• It was decided to allow the soil to flow but design foundation elements to withstand the immense pressures.

• SCCRC elected to have the design performed according to LRFD and HL-93 Modified (2006-2007 time period).

• Since typical pile sections would not be strong enough, a custom rectangular “box” pile was developed.

• The rectangular shape allowed the pile to be narrow (less likely to attract direct earth pressure) and deep for increased strength.


DESIGN DECISIONS

• Estimated deflections of the box piles was excessive, therefore ground anchors were proposed to anchor the pier footing from translating.

• The box pile and ground anchor foundation would be extremely expensive, therefore the following bridge design decisions were made:

• Use one pier only• Use a span long enough to locate the south abutment (Abutment A)

outside the unstable zone• Use conventional abutment designs• Use a symmetric span arrangement• Use a fixed bearing at the pier, use expansion bearings at abutments• Conventionally designed superstructure


DESIGN REFINEMENT

• As the bridge design progressed, URS was in daily contact with Somat to refine soil properties, provide new properties, refine dimensions of elements.

• Some of the items that were refined during the design, influenced by geotechnical issues, included:


• Box pile dimensions• Box pile socket

embedment due to scour• Diameter of excavated hole• No casing for excavation• Staging

• Socket details• Transverse earth pressures• Backfill around box pile• Arrangement of ground

anchors• Ground anchor length

BOX PILE DETAILS


• 2” x 40” webs.• 2¾” x 23” flanges.• 4’ embedment Into footing.• 20’ x 5’ diameter reinforced socket.• Interior filled with concrete.• Exterior filled with aggregate.

FINITE ELEMENT ANALYSIS OF PIER


FINITE ELEMENT ANALSYSIS OF PIER


• Deflections were calculated to determine the amount of in-service translation expected.

• Expansion bearings designed for translation.

• Deflections during tensioning of ground anchors calculated.

• Footing closure pour necessary.

PIER DESIGN

• During the pier design, Somat provided refined values of soil properties for the design of the box piles and ground anchors.

• URS’s analysis estimated approximately 1” of movement of the footing during ground anchor installation.

• During the actual installation of the ground anchors, the footing movement was measured at approximately 1”.

• Footing movement measurement was confirmation of design model.


FINAL BRIDGE CONFIGURATION


OTHER ITEMS

• Removal of the existing bridge was carefully considered. The removal of the existing pile bents was minimized to reduce vibrations on the unstable slope.

• There is a storm sewer that runs down the south slope. Due to the steep slope and the instability of the slope, the design and detailing of the storm sewer was carefully considered. Somat was consulted during the storm sewer design.

• A bridge health monitoring system was included. Load cells on the ground anchors and strain gauges on the piles were specified.


Thank You

QUESTIONS?

[email protected]@somateng.com

February 25, 2015

March 17, 2015Wadhams Road Bridge 24

FUNDING SOURCE

Funding Source Federal/State

Michigan Local Bridge Program $7,000,000

Surface Transportation $1,500,000

MDOT Funds $5,000,000

Local Bridge Programs $2,000,000

TOTAL $15,500,000

$11,600,000 (Bid Price)


Wadhams Road Bridge Replacement Bridging over a Moving...

Documents

Transcript of Wadhams Road Bridge Replacement Bridging over a Moving...