Best Practices Dennis Clausen Director of Training GOMACO Corporation Considerations for Profile Paving Stringline Installation & Maintenance Subgrade Stability and Accuracy Concrete Control & Placement Paving Basics Finishing Operations Other Considerations Stringline Installation & Maintenance Setting & Maintaining Accurate Stringline Recommend 25’ Surveyed Stations and Stringline Stakes, Closer Intervals in Horizontal and Vertical Curves. Stringline Installation & Maintenance Setting & Maintaining Accurate Stringline Recommend 25’ Surveyed Stations and Stringline Stakes, Closer Intervals in Horizontal and Vertical Curves. New Condition Cord, Wire, or Cable. Daily Maintenance & Checking of Stringline Elevation and Alignment. Daily Maintenance on Stringline Tightness. Subgrade Stability Stability of Paving Grade Unstable Grade Causes Thickness Control Problems if Haul Trucks are Placing Concrete on Grade. Possible Profile Problems if Subgrade continues to Move. Subgrade Stability Stability of Paving Grade Unstable Grade Causes Thickness Control Problems if Haul Trucks are Placing Concrete on Grade. Possible Profile Problems if Subgrade continues to Move. Stability of Track Line Track Line Failure may Occur Causing Profile Deviations. Subgrade Stability Stability of Paving Grade Unstable Grade Causes Thickness Control Problems if Haul Trucks are Placing Concrete on Grade. Possible Profile Problems if Subgrade continues to Move. Stability of Track Line Track Line Failure may Occur Causing Profile Deviations. Stability of Haul Road Safety Important because of Possible Delays in Concrete Delivery. In Extreme Cases may Affect Paver Track Line Grade. Subgrade Accuracy Accuracy of Paving Grade & Trackline. Fewer Changes in Elevation by the Paver, the higher probability of good profiles. Accurate Grade Elevation Makes Concrete • Placement More Consistent. Placing With Transit Mix Considerations if Transit Mix Must be Used Plant Should be Central Mix if Possible Mixer should be Designed as Paving Mixer Chutes Must be Kept Clean Control of Clean-out Water Must be Monitored Position and Placement of the Truck Mixer is Critical Placing Central Mix Concrete Positive Factors of Central Mix Placement: Most Efficient Mixing System, helping make a more consistent mix. Faster to Unload End Dump & Bottom Dump Trucks. Use of Placers & Placer Spreaders May: Allow the Paver to Move at a Consistent Rate of Speed. Allow the Paver to Operate with a Consistent Head of Concrete. Eliminate Large Piles of Concrete, which vary loading on the paver. Require Close Monitoring if Concrete Slump varies or if Subgrade is no Accurate Paving Basics Paving Basics For A Paver to Perform at Optimum it Must be: Paving Form Must be Clean Designed for the Width to be Paved Maintained According to the Manufacturers Recommendations Assembled and Adjusted to the Manufacturers Recommendations Operated by Trained Personnel Operated by Motivated Personnel Paving Crew Must Operate as a Team Paving Team must have Pride in Their work Extrusion Type Paving Form Must be Properly Adjusted for Good Paving Results. Establish a Set-Up Procedure and Follow it Religiously. Pan Should be Straight & True, Left to Right & Front to Rear. For Good Profile Results, Pan Should be Set Parallel to the Stringline Front to Rear. Check the Profile Pan for Accurate Setting after: – Width Changes – Moving the Machine Replace or Repair Damaged or Worn Parts When Necessary. Finish Procedures Good products Finish Procedures Good products Check product dimensions Finish Procedures Good products Check product dimensions Problem areas Finish Procedures Good products Check product dimensions Problem areas Start and finish headers GSI The Contractor’s Tool Before Paving Check smoothness of the sub-grade Check smoothness of the stringline setup Calculate yield of the paving materials based on sub-grade and stringline setup Pin point areas of cuts and fills in the sub-grade Stringline Sensor GSI Tools Analysis Software Sub base analysis for McCarthy Improvement in South Carolina With the GSI you can collect the same sub grade measurements every 2 inches GRADE CUT/FILL DETAILS STATION REFERENCE DEVIATION HEIGHT ROW INTERVAL RESOLUTION – 2”, 6”, 1’, 12’, 25’, 50’, 100’, ect. COLOR CODED CUT AND FILL PARAMETERS – BLUE = FILL – RED = CUT SLAB VOLUME NOMINAL SLAB VOLUME VOLUME DEVIATION THEORETICAL VOLUME (NOMINAL + DEVIATION) REPORT JOB INFORMATION TRACE DETAILS SLAB VOLUME PROJECT PARAMETERS GRADE CUT/FILL SUMMARY USER ADDED GRAPHS KNOWN FILE FORMAT FOR SHARING INFORMATION AND PRINTING – (*.HTML FILE USES INTERNET EXPLORER FOR VIEWING AND PRINTING) GSI The Contractor’s Tool During paving process Provide paving crew immediate smoothness readings right out of the paver – Corrections may be made to the pavement surface while concrete is still in plastic condition – Adjustments can be made to paving operation before thousands of feet have been paved Separate machine can be backed over the repaired surface to take readings again Check Profile of Poured Concrete Behind Paver Check Profile of Poured Concrete Behind Paver Check Profile of Poured Concrete Behind Paver Check Profile of Poured Concrete Behind Paver View 2 Traces View Report in PI or IRI Format 3D Stringless Control System for Curb & Gutter, Trimming & Concrete Paving What is Stringless 3D? A 3D Machine Control system that simplifies jobsite logistics, reduces costs and improves quality and safety Removes stringlines and pins from the jobsite Removes install, maintenance & removal costs Increases working safety, especially at night Puts the 3D job design directly onto the machine Eliminates setting-out errors and stringline influences No waiting for setting-out before production No dependency on setting-out – work wherever you have 3D data Increases productivity, quality and performance bonuses Controls height, slope (and steer) of machines 58 Delivers a precisely-constructed product Optimises amount of new material needed Reduces over-trimming, overpouring Improves concrete yields and material cost savings Working with Stringline… Inspect design – calculate setting-out lists for each lane Setup a theodolite, survey each hub or pin position with total station (or GPS if accuracy isn’t important!) Hammer (or drill) in each pin, minimum 1 line for each lane of concrete/asphalt Check pin alignment & adjust if required Survey and set stringline height on each pin (min. 2 men) Install & tension clamps and stringlines Reference Point “Eyeball” & adjust stringlines before paving Move machine into position, set sensors to stringline Check machine position relative to stringlines Start Production, monitor machine position Ensure (or hope!) nothing disturbs or damages stringlines during paving/milling… 59 Walk left 5ft! Walk right 1ft! Up a bit! Down a bit! STOP! Reference Point Mainline Slipform Paving & Fine-Grade Trimming with Stringless 3D Click to return to Main Menu Why go “Stringless”? Could your paving projects benefit from… …no marking-out and drilling to setup pins and guidewires? …easier paving in “zero clearance” situations, e.g. bridge decks, urban streets, railway cuttings, tunnels, narrow motorway lanes? …no special access/safety equipment to pave in tunnels? …no pre-production planning – just arrive, pave anywhere, any time? …no human error from stringline setup? …no inaccuracy of “field model” compared to original “office design”? …lower material costs, improved concrete yield (less waste)? 61 Why go “Stringless”? Because stringlines… … are expensive, time-consuming and error-prone to install … can be easily damaged during paving … can be easily misaligned … can be a significant site safety hazard … interfere with site logistics, increase concrete delivery time, haulage costs, and reduce productivity. … require pre-production planning & increase survey effort/cost … don’t always “model” the designed surface accurately 62 What is 3D? A 3D Machine Control system simplifying slipform jobsite logistics, reducing cost, improving quality and productivity Specifically designed for mainline (slab) pavers & trimmers The result of 16 years worldwide experience in 3D slipforming Developed in close cooperation with GOMACO Eliminates stringlines (“stringless control”) Controls paver elevation, steer, slope and draft Constructs directly from the 3D plans Removes need for stringline set-out crew Minimises pre-production planning and preparation 63 Stringless System for Gomaco Trimmers System Components Reference Point Reference Point Prism Machine Computer Radios Slope Sensor 64 Theodolite #1 (Guidance) Theodolite #2 (As-builts & Leapfrog) Stringless System for Gomaco Placer/Spreaders System Components Machine Computer Radio Slope Sensor 65 GPS or Prism GPS Reference Station Stringless System for Gomaco Pavers System Components Prism Machine Computer Reference Point Prism Radios Slope Sensors Reference Point 66 TPS #3 (As-builts & Leapfrog) TPS #1 (Guidance) TPS #2 (Guidance) Faster, more accurate trimming… Optimal subgrade saves concrete and improves rideability 67 Smoother airfield paving… Increases runway life, reduces undercarriage & tyre wear 68 Smoother road paving… Increases road life, reduces vehicle wear & passenger fatigue 69 Practical Issues… In the field! 70 Practical Issues Checking concrete (or subgrade) level and position The third theodolite together with a prism measures the surface “as-built” behind the machine Errors (and adjustments) shown on theodolite Report stored on 3D computer 71 Practical Issues Adjusting the Machine If the level needs adjusting… …just like stringline control we can adjust all leg heights, and draft independently, without stopping paving 72 Practical Issues Adjusting the Machine If position needs adjusting… …just like stringline control we can adjust position at front and rear independently, without stopping paving 73 Practical Issues Moving the Theodolites (‘Leapfrogging’) Maximum Range Theodolite-to-Paver is <= 200m (*depends on conditions) We don’t want to stop the paver for too long! Before maximum range is reached, move 3rd Theodolite to new position & setup (Position & Orientation Fix). Press ‘Swap Theodolite’ on computer System switches control from #2 (or #1) to #3 Theodolite automatically Move ‘old’ Theodolite to new position, setup and repeat procedure Ensure enough Reference Points visible for Setup (Position & Orientation Fix) * - temperature, humidity, air quality 74 Questions? Dennis Clausen Director of Training GOMACO Corporation
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