Presented By: Marvin Burns, PE Janssen & Spaans Engineering, Inc. Practices needed during design, shop drawing preparation and construction of long span post-tensioned bridges 2 Construction Techniques Spliced, Post-tensioned, Precast Girders Cast-In-Place Balanced Cantilever I-355 Bridge over Des Planes River Valley 270’ main span - Illinois Tollway Authority Design Build SMART Bridge 472’ main span - Virginia DOT Construction Engineering Presented By: Marvin Burns, PE Janssen & Spaans Engineering, Inc.

Responsibilities Design Engineer Adequacy of design Provide details that are workable with only minor conflicts that can be resolved in the shop drawings Erection Scheme that meets industry practices Construction Engineer Preparation of Shop Drawings for each segment that combines various elements shown on contract plans with erection hardware and post-tensioning hardware. These items often have proprietary details and cannot be finalized until the Supplier has been selected. Shop Drawings showing placement of rebar with minor repairs from that shown on contract plans to avoid post-tensioning anchorages and ducts.

Responsibilities Construction Engineer for Cast-In-Place Balanced Cantilevers Provide detailed erection analysis based on Contractors Erection Sequence and Calendar. Analysis includes stress/capacity design checks for each step of erection; including time effects for creep and unbalance moments during weekly cycles. Services include camber diagrams made from the deflections and procedures to control geometry for erection segments. Calculations for tendon forces and elongations using friction coefficients associated with the tendon duct supplied by the post-tensioning supplier.

Contractor / Construction Engineer The Construction Engineer’s duties and responsibilities are described in, and governed by, a written contract with the Contractor. Duties will generally include requirements imposed by the Owner in the special provisions. Contract documents usually contain minor conflicts. Although many of these are caught and cleaned up during preparation of the shop drawings there is an expense in money and time associated with how much detail is needed by the Contractor to be able to build from the shop drawings. The Contractor has tight schedules and cannot wait for shop drawings to be perfect before work proceeds. At a certain point the Contractor has to cut off the planning stage and get on with the work.

Spliced, Post-tensioned, precast concrete girder US 27 over Caloosahatchee Canal Moore Haven, FL 3 Spans (210’-320’-210’) 320’ National Record held by JSE Completed Winter 2001 KY 22 over Kentucky River Gratz, Ky 4 Spans (175’-200’-325’-200’) 325’ National Record held by JSE Completed Summer 2010 Featured in Aspire magazine in Winter 2011

I-355 Bridge over Des Plaines River Valley Illinois Tollway Authority Performance Based Alternate 35 Spans divided into 8 Units - 2 structures at 6,600 ft each 102” Deep Post-Tensioned Bulb Tees, PT Beams Haunched to 120” on Main Spans 90” Prestressed Beams Post-tensioned Spans Ranged from 216’ to 271’ Prestressed Spans Ranged from 114’ to 170’ Completed Winter 2007

Post-Tensioned Beams Spans Ranged from 216 ft to 270 ft Beams Ranged from 113 ft to 150 ft

Post-Tensioned Beams Typical Beam Depth – 102 in Beams haunched over Piers to 120 in Brian

Post-Tensioned Beams Falsework Required Strongbacks Brian

Post-Tensioned Beams 4 Tendons Per Beam Line Brian

Post-tensioning

Post-tensioning

Tendon Grouting

Final Cost $125M Low bid - including engineering fees $133M Second-place bid for Segmental Concrete Box Alternate $147M Third-place bid for Steel Performance-Based Alternate Bids include approach roadway and adjustment of features crossed Brent

SMART Bridge – Virginia DOT Christiansburg, Virginia Construction Engineering Contractor: PCL Civil Constructors Construction Cost: 15 Million Completion: 2000 5 Spans (284’-3 at 472’- 284’) = 1984’ Width = 36’-4” Single Cell Box (2 Webs)

SMART BRIDGE Concrete Pour using Tire Crane

SMART BRIDGE Erection of Pier Table Erection of Form Traveler

SMART BRIDGE

EB Wakota Bridge– Minnesota DOT Minneapolis, Minnesota Construction Engineering Contractor: Lunda Construction Construction Cost: $63 million x 2 bridges = $126 million Completion: 2010 5 Spans (272’-328’-2 at 466’,358’) = 1890’ Width = 85’ typical and 105’ at end spans for acceleration lanes DoubleCell Box (3 Webs)

EB Wakota Bridge Front View Side View Erection of Pier Table

EB Wakota Bridge Erection of Form Traveler

EB Wakota Bridge Pouring of Segment using Pair of Pump Trucks

EB Wakota Bridge

Construction Loading PERMANENT EQUIPMENT Shear Transverse Shear on Leading Edge Actual Wt. vs. Plan COG 1.4x Shear at Leading Edge

Construction Loading PERMANENT EQUIPMENT Shear Transverse Shear on Leading Edge Actual Wt. vs. Plan CONSERVATIVE MAX IDEALIZED ORIGINAL DESIGN CONST. DISTRIBUTION

EB Wakota Bridge Inside View of Left Cell of Double Cell Box

General Structure Size Balanced Cantilever Construction

Rebar Congestion Double Cell Box Wide double cell boxes can have larger tendon forces. It would make it easier to install confinement rebar for the anchorages if the concrete dimensions could be enlarged. Single Cell Box

Rebar Congestion

Vertical Tendon Radial Force Tendon Stressing Operation Concrete Spall

Vertical Tendon Radial Force Tendon Pop-Out Vertical Radial Force

Vertical Tendon Radial Force Tendon Radial Force is Unrestrained Vertical Legs are Too Far Apart Tendon Radial Force is Restrained

Stirrups to Restrain Angle Change at Bulkheads

Tendon Radial Force Variable Height Box

Horizontal Tendon Radial Force

Horizontal Tendon Radial Force

Tendon Cross Over into Adjacent Duct

Horizontal Tendon Radial Force Concrete Removal

Tendon Duct is Crowding Anchorage Reinforcing

Tendon Duct is Crowding Anchorage Reinforcing

Questions Thank You