Bayshore PCEF - Spliced Girders Spliced Girders A...

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Unformatted text preview: Spliced Girders Spliced Girders A Producer’s Perspective by Chad Saunders Chief Engineer Bayshore Concrete Products presented at the Virginia Concrete Conference Richmond, Virginia March 11, 2005 Bayshore Concrete Products Bayshore Concrete Products Cape Charles, VA 90 acre casting facility on Cape Charles Harbor and Chesapeake Bay The shape. How did we get here? The shape. How did we get here? PCEF Prestressed Concrete Committee for Economic Fabrication A committee established by FHWA for economic fabrication of prestressed/precast concrete Consists of Mid Atlantic states PCEF Cross Section Variability PCEF Cross Section Variability 6” 7” 8” Different web thicknesses = diff. soffit PCEF Cross Section Variability PCEF Cross Section Variability 58” 59” 60” 12” wider top flange = same side form with blockout removed Form modification Form modification VDOT PCBT VDOT PCBT 32” bottom flange width 7” thick bottom flange 7” web 47” top flange width DESIGNATION DEPTH AREA (IN) (IN2) (IN) X 103 (IN4) LBS/LF PCBT-29 29 634.7 14.66 66.8 661 PCBT-37 37 690.7 18.43 126.0 720 PCBT-45 45 746.7 22.23 207.3 778 PCBT-53 53 802.7 26.06 312.4 836 PCBT-61 61 858.7 29.92 443.1 899 PCBT-69 69 914.7 33.79 601.3 953 PCBT-77 77 970.7 37.67 788.7 1011 PCBT-85 85 1026.7 41.57 1007.2 1070 PCBT-93 93 1082.7 45.48 1258.5 1128 CENTROID TO BOTTOM MOMENT OF INERTIA WEIGHT (150 PCF) Rte 123 over the Occoquan River Rte 123 over the Occoquan River Fairfax and Prince William Counties VDOT’s first PCBT spliced girder bridge Location Location Close proximity to I­95 and Route 1 = detour = high traffic Town of Occoquan Town of Occoquan Affluent neighborhood = pressure for aesthetic design Who’s Who Who’s Who Owner – VDOT Designer – Moffatt & Nichol General Contractor – Archer Western Erection Engineer – McNary Bergeron Precast – Bayshore Concrete Products PT Hardware ­ VSL Erection plan Erection plan Approach Girders (4 spans) End Span Haunch Drop In Haunch End Span Bridge Cross Section Bridge Cross Section At Haunch Piers Other piers Concrete Concrete Concrete – 28 day: 8000 psi Concrete ­ release: 5800 psi Low permeability Release strength cylinders matched cured Approach Approach Girders 4 span unit Pieces: 58 total beams Type: PCBT­77 Length: 144 ft Weight: 73 tons Strand: 0.6” LRS Cast two per pour Cross section Approach Girder Casting setup Approach Girder Casting setup Gravity abutment to withstand prestress force Conventionally prestressed with draped strands Maturity meter testing Maturity meter testing Research for more accurate prediction and control of camber by VA Tech Forms and casting Forms and casting Side forms with fall protection rail Placing concrete with Tuckerbuilt Storage Storage 300 ton twin gantry crane in background End span Spliced Girders Spliced Girders Pieces: 28 total beams Length: 127 ft Weight: 88 tons Haunch Pieces: 28 total beams Length: 98.5 ft Weight: 77 tons Drop­In Pieces: 14 total beams Length: 137 ft Weight: 87 tons Special form needs Special form needs End span and Drop­In 34” soffit (4) sections of end block form (end span only) Extra 2” angle full length of side forms to create 6” thick top flange Haunch Complete form system including soffit and side forms Approach Standard PCBT­77 Erection Sequence Erection Sequence Temporary support Erect haunch segment then end span segment Back span = 185 ft Erect drop­in segment Main span = 225 ft Erection Sequence Erection Sequence Make closures and begin PT Remove strong backs Cast deck and complete PT End Span and Drop In End Span and Drop In cross sections Type: Modified PCBT­77 Depth: 79” Strand: 0.6” LRS Variations: 6” thick top flange 9” wide web for PT tendons = 34” wide bottom flange & 49” wide top flange Cast two per pour End Span and Drop­In End Block at End Span End Span End Span PT ducts: (3) 4” OD for 0.6” LRS end condition Extremely congested area due to bursting reinforcement End Span and Drop­In connection End Span and Drop­In connection at splice with haunch Very congested area due to splice plates with welded rebar and projecting rebar Casting setup Casting setup Ducts in place Setting ducts End block End block Up close near anchorage Horizontal reinforcement End block End block Termination of end block Pre­assembly of end cages Splice End Splice End Top splice plates Bottom plates and projecting bars Haunch Haunch Type: Modified PCBT­77 Depth: varies from 79” to 12’­6” Strand: 0.6” LRS Variations: 6” thick top flange 9” wide web for PT tendons = 34” wide bottom flange & 49” wide top flange Cast one per pour Haunch Haunch NTS Challenges: nts 12’­6” depth at midpoint = extreme height full length Most strands located in top flange Location of the PT tendons makes concrete placement and consolidation difficult = addition of pour windows Extra setup required for storing and handling of variable depth side forms and beams Bed setup Bed setup Pulling strand Pulling strand Stressing Stressing Rebar and Rebar and PT tendons How did he tie the bars in How did he tie the bars in the top flange? Forms Forms Grout vents Top Splice Plate Top Splice Plate Look at the view from up here. Pouring with buckets Pouring with buckets First casting is a success Girder bracing Girder bracing Shipping Shipping All beams to be shipped by barge starting early April 2005 Erection Erection Phase I – setting beams from the existing bridge Erection Erection Phase II – setting beams from the phase I bridge Lessons learned Lessons learned Producer ­ Seek possible use of SCC concrete for heavily congested area Contractor ­ Get “construction engineer” involved early to ensure means and methods are established (i.e. temporary bracing embedments, special lifting requirements, strong back design, etc.) Engineer ­ Require complete shop drawings from PT supplier DOT – consider having a notch in back span girder(s) designed and included in plans to ensure maximum flexibility in construction sequence Rte 33 over the Pamunkey River Rte 33 over the Pamunkey River West Point and New Kent County What’s Next? Location Location Town of West Point Town of West Point Who’s Who Who’s Who Owner – VDOT Designer – Parsons Brinckerhoff General Contractor – Tidewater Skanska Precast – Bayshore Concrete Products Concrete Concrete Concrete – 28 day: 8000 psi Concrete ­ release: 6000 psi Low permeability Lightweight: 115 pcf (concrete) 125 pcf (total) Approach Approach Girders 3 span unit Pieces: 21 total beams Type: Modified PCBT­93 Variations: 9” thick bottom flange 8” wide web = 33” wide bottom flange & 60” wide top flange Depth = 95.5” Length: 137 ft Strand: 0.5” LRS Cast two per pour Cross section Spliced Girders Spliced Girders End span Pieces: 42 total beams Length: 159 ft Haunch Pieces: 28 total beams Length: 80 ft Drop­In Pieces: 28 total beams Length: 159 ft Haunch Haunch Type: Modified PCBT­93 Depth: varies from 95.5” to 10’­5 1/2” Strand: 0.6” LRS Variations: 8” wide web for PT tendons = 33” wide bottom flange & 60” wide top flange Cast one per pour Challenges: 10’­5 ½” depth at midpoint = setup remains at 12’­6” to avoid costly rework = extreme height full length Others same as previous project. Pros: Not having to set up a new stressing frame Booster Form – utilize existing forms Haunch Haunch Special form needs Special form needs End span and Drop­In 33” soffit (2) sections of end block form (end span only) – different from Occoquan because same quantity of end span and drop­in 16” riser for PCBT­77 form Haunch Booster form (bolts on to bottom of standard form) Approach 16” riser for PCBT­77 form (same as above) Questions? Questions? Thank You Thank You Please feel free to come visit our plant OR call if we can be of assistance in any way Contact: Joe Rose 757­331­2300 [email protected] Bayshore Concrete Products Bayshore Concrete Products Cape Charles, VA 90 acre casting facility on Cape Charles Harbor and Chesapeake Bay ...
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This note was uploaded on 05/22/2011 for the course CIVIL ENGI 101 taught by Professor Merrayan during the Spring '11 term at CSU San Bernardino.

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