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

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Presentation on theme: "Construction Sequencing I-15, Ontario, CA HFL Show Case, June 22, 2010 Peter J. Smith, P.E. The Fort Miller Co., Inc."— Presentation transcript:


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

3 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

4 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 The Super-Slab® System (JPCPS) – Key Features

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

6 Bedded (primarily) With Precisely Graded Fine Aggregate Material SIZEWCS #499 #888 #1665 #3037 #5015 #1005 #2001.8 FM2.91 Fine Bedding Material Fully compacted subgrade Acts as cushion on CTB Bond breaker between CTB and new slabs Provide grade control for new slabs

7 Installing Bedding Grout Bedding Insured By Filling Voids (if they exist) With Bedding Grout Foam Gasket Grout Distribution Channel Used only to fill voids Flow rate : 17 – 20 seconds 600 psi in 12 hours Proof

8 Two Types of Slabs Slab shape depends on geometry of pavement surface Single Plane Warped Plane

9 Super-Slab 3D Technology (x4, y4, z4) (x1, y1, z1) (x2, y2, z2) (x3, y3, z3) 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

10 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!)

11 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

12 Design Profile Development New Profile Kept Within Grinding Distance of Existing Edges

13 Developed Panel Data

14 Slab Layout Drawing

15 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

16 Step by Step Installation Details (what you will see tonight)

17 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 Step 1 – Lay Out Slabs

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

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

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

21  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)

22 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

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

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

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

26 Setting H.O. G. Rails

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

28 Step 5 Placing Slabs(the easy part) 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.)

29 Prior to Placing Slabs Check with Depth Gage Trim with Edge Trimmer (below) Bond Breaker on Transverse Edge Shims on Leading Edge Corners

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

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

32 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

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

34 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

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

36 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

37 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

38 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)

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

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

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