2015 nace daytona_gsp

MEHAFFEY BRIDGE CONSTRUCTIONMehaffey Bridge Road Structure G-32-1 over the Iowa River at Coralville LakeProject #LFM-MEH BR--7X-52

PRESENTATION OUTLINE

• Introductions• Project Background• Structural Highlights• Construction Challenges• Questions

INTRODUCTIONS

APWA Spring Conference March 27, 2015

YOUBrilliant, engaged professional

Your job today:◦ Actively engage in the discussion◦ Learn a little something◦ Ask questions

PROJECT BACKGROUND


ORIGINAL RESERVOIR BRIDGE

49 years old (started 1964, completed 1966) Cost to Johnson County - $100,000

($6.55/SF) Structurally deficient (posted 10%), SR=33.3 28’ Width not suitable for current/expected

traffic levels Subject to closure during 1993/2008 level

flood events


NEW MEHAFFEY BRIDGE DESIGNDesign Constraints/ Project Goals

Design for better flood resistance Capable of handling 4-lane traffic Include a multi-purpose trail Maintain traffic during construction (Current: 3700,

Design 5500 AADT) Open waterway by minimizing number of piers to

allow for better recreation traffic Do it all for $3M


NEW MEHAFFEY BRIDGE DESIGNAlternatives Considered

Do nothing/repair Conventional IDOT bridge (PPCB) Hump-Back Steel Cantilevered Pre-Stressed Concrete 2-Pier

Design Cable-stay bridge (End or Center

Support) Something else???


NEW MEHAFFEY BRIDGE DESIGNJacobsen BridgeEXTRADOSE

D


NEW MEHAFFEY BRIDGE DESIGN

Flood resistant at 1993/2008 Levels (Elev. 717.00)

565’ x 55’ = 31075 SF 2 traffic lanes (40’ Roadway), 12’ Multi-Use Path Long span = 112’ (BTC) Traffic maintained on the old bridge throughout

sub-structure construction Only 2 piers in the water Distance from pier to pier = 224’ Contract amount = $8.9M ($286/SF)

STRUCTURAL HIGHLIGHTS


REDUNDANCYWhen Might Sometimes Makes Right

HAMILTON COUNTY, OH — On the night of Tuesday, May 20, 2008, a flatbed trailer carrying an old 80-ton locomotive broke free from its truck hitch. The trailer drifted forward along the southbound lane of I-275 and crashed into a pier supporting the eastbound I-74 overpass.The 32-year-old steel bridge sagged, but didn’t collapse. Eastbound traffic on I-74 traveled over the damaged bridge for about 10 minutes before officials arrived to close the bridge and reroute traffic.


DIAGONAL SECTION

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DIAGONAL POST-TENSIONING END ANCHORAGE


DIAGONAL AND PIER VIEW


END OF DIAGONAL (KNUCKLE)


KNUCKLE/SUSPENDED FLOOR BEAM


SUBSTRUCTURE/KNUCKLES


FLOOR BEAM SECTION


FLOOR BEAMS


FLOOR BEAM POST-TENSIONING ANCHORAGE


PUTTING IT ALL TOGETHER


REDUNDANCY MET

Multiple stringers Diagonals and floor beams have multiple

rebar and two systems for reinforcing. Prestressed beams will be continuous for

extreme event and will carry in the event of loss of a diagonal or floor beam.

CONSTRUCTION CHALLENGES

It’s an expensive, unique design - what could possibly go wrong?


DETAILS, DETAILS, DETAILS


CONDITIONS


TRAFFIC/THE PUBLIC

A recent count showed almost 5k AADT◦ They are not patient◦ They will not go around

The expectation is increasingly - zero delays Accelerated Bridge Construction

◦ 90 day critical closure incentive/disincentive◦ We build the new bridge, from a traffic impact

perspective, in approximately 3 months◦ Tier 5 ABC - Definitely◦ Tier 4 ABC - Most likely

How do we manage expectations???


COMMUNICATIONSQR Code Road Signs

Website

Twitter

Dynamic Message

Signs


COMMUNICATIONSDynamic Speed Signs

QR Code

Public Informational Meetings

Press ReleasesRadio Spots


PROJECT STAGING

◦ Stage 1 - Construct the towers◦ Stage 2 - Construct Diagonals, Floor Beams,

Compression Struts and Knuckles◦ Stage 3 - Construct Trail portion of the deck◦ Stage 4 - Switch traffic, demo old bridge,

complete deck and paving


STAGE 1


STAGE 2


STAGE 3


STAGE 4


THANK YOU!

A special thank you to:◦ Johnson County Board of Supervisors◦ VJ Engineering◦ Steve Jacobsen, SE◦ Iowa Bridge & Culvert, LC◦ The US Army Corps of Engineers◦ The Iowa Department of Natural Resources


CONTACT

Greg S. Parker, PE◦ Johnson County Engineer◦ 4810 Melrose Avenue West◦ Iowa City, Iowa 52246◦ 319.356.6046◦ [email protected]

QUESTIONS?

2015 nace daytona_gsp

Education

apwa spring conference

old bridge

bridge end

damaged bridge

yearold steel bridge

original reservoir bridge

pier design cable

lane traffic