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  1. Construction Sequencing I-15, Ontario, CA HFL Show Case, June 22, 2010 Peter J. Smith, P.E. The Fort Miller Co., Inc.

  2. The Fort Miller Co., Inc. Precast Concrete Company Located in upstate New York Transportation-related precast products for 9 Northeastern States Specializing in accelerated bridge (and other structures) construction Currently exporting precast pavement technology (Super-Slab®) to other states Provides design assistance to DOT’s Provides forming equipment and training to local precasters Provides specialized grading equipment and on-site training to contractors and DOT inspectors

  3. The Super-Slab® System (JPCPS) – Key Features • Simple slab-on-grade system • Standard dowels and tie bars (JRCP) • Built-in bedding grout distribution (to insure full and complete support) • Techniques for precision grading • Capability of providing 3-dimensional surfaces

  4. Dowel and Tie Bar Connection Bedding Grout Port • Slots on the bottom protects grout from de-Icing chemicals • Dove tail slots provide resistance to dowel pop-out Dowel Grout Port Dowel Grout 2500 psi before traffic

  5. Bedded (primarily) With Precisely Graded Fine Aggregate Material • Fine Bedding Material • Fully compacted subgrade • Acts as cushion on CTB • Bond breaker between CTB and new slabs • Provide grade control for new slabs

  6. Grout DistributionChannel FoamGasket Proof Bedding Insured By Filling Voids (if they exist) With Bedding Grout • Used only to fill voids • Flow rate : 17 – 20 seconds • 600 psi in 12 hours Installing Bedding Grout

  7. Two Types of SlabsSlab shape depends on geometry of pavement surface Single Plane Warped Plane

  8. Super-Slab 3D Technology • Develop digital surface model of the pavement • Extract “x”, “y”, “z” values (from model) for every corner of every slab • Use values to fabricate slabs in specially designed forms • Use same values to prepare subgrade surface (x3, y3, z3) (x2, y2, z2) (x4, y4, z4) (x1, y1, z1)

  9. What We Are Emulating Concrete Pavement Fully Bedded With Accurate Surface Effective Load Transfer Dowels at Joints (to be sawed) (If you can possibly cast good concrete in place and get a good cure, don’t use precast!)

  10. Engineering & Design Contractor collected field survey data (prior to shop drawing development) Random slab replacement (patches) – widths only of each hole Continuous installations Collected accurate “x”, “y”, “z” data of existing edges to be matched Fort Miller developed: Design edge profiles and slab layout drawings Shop drawings (detailed piece drawings) Drawings completed months in advance of actual installation To allow time for fabrication

  11. Design Profile Development New Profile Kept Within Grinding Distance of Existing Edges

  12. Developed Panel Data

  13. Slab Layout Drawing

  14. Panel Fabrication Fort Miller partnered with local precaster for slab fabrication Fort Miller provided: Specialized forming equipment Training for precaster personnel Continuous check of slab dimensions Periodic check of slab quality Precaster: Fabricated, stored and shiped slabs Provided QC and QA Coordinated shipping to contractor

  15. Step by Step Installation Details (what you will see tonight)

  16. Continuous installations must be laid out with total station equipment Must replicate original “x”, “y”, “z” survey Grades for off-set rail must be calculated Leading edges (Panel points) must be laid out Step 1 – Lay Out Slabs

  17. Lay Out Slabs Accurately Grade Grade Shim Leading edge mark and panel point grade (cut or fill mark) Leading Edge Use total station (preferably) to layout continuous installations (leave marks that will last)

  18. Step 2 – Saw Cutting Allow enough room to prevent spalling during removal Make Full Depth Cuts (don’t try to do it in one pass!) Cut in sizes for easy removal

  19. Step 3 – Removal Slab crab bucket most efficient (and can be used for removal of existing CTB) Use right size (and enough) trucks!

  20. Super-Grading The process of grading fully-compacted bedding material to a surface accuracy of + 3 mm Requires specialized grading equipment Using an accurate frame of grade reference The grade of the adjacent pavement rarely accurate Step 4 – Precision (Super) Grading (Important Key Operation)

  21. Provides accurate grade control for slabs Set slabs only once Provides “nearly complete” subgrade support without grout Slabs can be opened to traffic right away Minimizes volume of bedding grout required Allows un-grouted slabs to be used immediately Benefits of Super-Grading

  22. Milling High Cement Treated Base Truck mounted sweeper Milling high CTB (to allow room for bedding material)

  23. Installing Bedding Material Bedding Material Storage Use Skip Loader (Skippy) (For moving and rough grading)

  24. Small Scale Grading Equipment Rail Supported and Hand Operated Auger H.O.G. Hand Operated Grader (H.O.G.) Mini-H.O.G. Shutter Screed

  25. Setting H.O. G. Rails

  26. Continuous Grading With H.O.G. Three Steps First Pass (1/4” high) Last Pass (done) (over 500 LF per night possible) Compaction

  27. Step 5 Placing Slabs(the easy part) • Slab Sizes • Thickness – 203 mm • Width – 3.66 & 3.96 m • Lengths – 3.66, 4.57, 4.27, 4.57 m • Weight – 9 Ton (max.)

  28. Prior to Placing Slabs Bond Breaker on Transverse Edge Check with Depth GageTrim with Edge Trimmer (below) Shims on Leading Edge Corners

  29. Placing Slabs Placement Crane Occupies Un-grouted Slabs to Set More Slabs Keep Outriggers Off Slabs (if Possible)

  30. Placing Slabs To Panel Point Marks String Line Setting Crew One Man in Each Corner Setting To Leading Edge Marks

  31. Step 6 - Dowel Grouting Dowel Grout is “hot grout” Reaches 2500 psi in two hours Keep mixture below 60 degrees Use Ice Water to Control Temp. Use Proper Nozzle Keep Dowel Grout Moving Do not let it sit in hoses Wash Out Grout Pump Frequently 15 minutes per slab

  32. Installing Dowel Grout Contractor-Designed Joint Dam (clean up dowel grout immediately) Fill Dowel Slots and Joints First (keep it moving)

  33. Bedding Grout Mixture of Cement, Water & Admixture Flow rate of 17 - 20 seconds Must flow into thin voids Reaches 2 MPa + in 12 hours Use Proper Nozzle Keep Holes filled

  34. Installing Bedding Grout Proof Pre-bagged Bedding Grout Flow Rate of Bedding Grout 17 – 22 Seconds

  35. Joints Treated as construction joints (in CIP) Maximum width < ½” As placed joints vary from 0” to ½” Joints are filled with dowel grout Bond breaker on one side of joint Top 2” sawed to uniform ½” width and sealed with silicon sealant Skewed Joint (Existing) Transverse Joint

  36. How About Smoothness? Small differences between slabs are to be expected There are tolerances allowed (by necessity) in the slabs There are tolerances allowed in the grading Super-Slab® specifies finished surfaces + 1/8” May be acceptable for slow speed traffic For best International Roughness Index - grind Grinding is a known and accepted practice

  37. Production Rates Grading, Placement, Grouting Rates 8 – 10 Slabs (1500 – 2000 SF) per Hour 12’ x 13.5’ (avg.) slabs Average rate on this project 39 slabs (in about 6 hours) per shift 526.5 LF. = 6300 – 6800 SF per Shift Maximum production rate 52 slabs = 702 LF. = 8424 SF (in one night)

  38. Precast Pavement is Premium Pavement Under Pressure A Good Tool For Difficult Locations

  39. Keys to Success(Still More to Learn) Good engineering Open minds Real partnering