1 Salt Palace Convention Center TRACK C: AIRSIDE ENGINEERING WORKSHOP: 2 Title: Technology Advancements in the Field: Stringless Paving Speaker: Gary L. Mitchell, P.E., ACPA Date: March 2, 2016
2 Stringless slipform paving technology
3 Already being done at numerous airports around the country Placing concrete. -- a. Slip-form construction. The concrete shall be distributed uniformly into final position by a selfpropelled slip-form paver without delay. The alignment and elevation of the paver shall be regulated from outside reference lines established for this purpose.
4 Introduction What is Stringless Paving? Alternative to conventional stringline paving. Uses electronic guidance systems to replace pins, sensors, and stringline. Electronic guidance system controls elevation and steering of the paving machine(s). Sometimes referred to as 3D paving.
5 The concepts are similar, but there are options for the technology employed Combinations of these technologies. Robotic Total Stations. Laser surveying. Global Positioning Systems. 3D models.
6 Timeline of Development 2013 Use is Growing First Published Research (Iowa) 2003 First Highway (Belgium) 2001 First Airfield Paving (Various) 2000 First Street (Iowa) 1999 First Paving, Curb & Gutter (Alabama) s Paver Controls Refined s Earthwork Controls Developed and Refined
7 Step 1 Create survey control network. Step 2 Collect field survey data of existing surface. Step 3 Design pavement/create 3D model; convert data for machine inputs. Step 4 Transfer simplified model to the paving machine, set up 3D instruments, tie into controls; then pave. STEP 1 STEP 2 STEP 3 STEP 4
8 Similarities and Differences
9 Accurate Surveying is Required! March 2-4, 2016 Both stringless and stringline paving methods require establishing a control network (or reference) for accurate paving. A string control method requires more labor intensive surveying to transfer the plan geometry to the grade. Stringless paving requires additional equipment, training and 3D data to build the pavement to plan. Both methods work and the accuracy of either starts with the survey controls!
10 Basic Differences Use of Technology March 2-4, 2016 How design data is used. The number of surveyed control points needed to control the paving machine. The opportunities for survey error. The trueness of the line and grade that the machine follows. Engineering plan and profile is transferred to grade by a survey crew for stringline-controlled paving. Engineering plan and profile is converted to 3-D model for stringless paving machine control.
11 Working With Stringlines Requires Many Steps Survey Reference Point Benchmark Control Points (Paving Hubs Pins) Stringline survey crew must set up each paving hub individually for stringline-controlled paving. There are many chances to introduce or compound errors.
13 Stringline Surveying Setting Grade on the Stake.
14 Field Surveying and Set-up Requirements for Stringless Paving Establish Control Network: Control points established from field surveying. 2 person crew. Control points tied to known benchmark(s). Should be positioned: Out of way of any operations. Where they will not be bothered by the public. To allow instruments for machine control to see at least three control points at all times.
15 The Typical Steps Working With Stringless Paving 1. Surveying control point locations in the field at about 250 ft intervals for total station control and even greater intervals for laser or GPS control. 2. Placing each control point. 3. Performing automated surveying of the project site to build the terrain model. 4. Developing 3D model from plans. 5. Error-checking the 3D model. 6. Setting up instruments on the grade and tying them into at least three control points for paving. 9. Moving machine into position & checking (validating) the pan elevation using the instruments before paving. 10. Checking radio and/or laser communication between instruments and paver. 11. Moving the instruments along the grade as paving progresses.
16 Benchmark Control Points The stringless survey crew must plan the location of control points. The number depends on terrain, urban development and instruments (total station, laser or GPS)
17 Time Efficiency Improvements with Stringless Reduces field surveying. Eliminates labor intensive stringline surveying for hubs and stakes. Eliminates need for string line, stakes and accessories. Reduces opportunities to introduce surveying errors. Reduces overall preparation time on the grade. These efficiencies will save construction costs while the technology will improve paving quality!
18 Spatial Requirements Reduced with Stringless 5 ft. Stringless technology helps increase feasibility of concrete paving in tight areas. A string-controlled operation requires about 5 feet clearance on each side: 3 ft. for paver track and workers. 1 ft. for hubs and stringline stakes. 1 ft. for safety devices A stringless operation requires 1-2 feet less clearance on each side. Benefits: Increases phasing and traffic control pattern considerations. Improves project feasibility. Provides safer access to grade for crew and trucks.
19 Machine Control Improvements with Stringless Places engineer s design directly into machine(s). Controls elevation, slope, and steer of machines with truer input. Reduces or eliminates cords created by stringline hubs/pins. Reduces wave patterns introduced by improperly tensioned stringline sensors. The control points that link the 3D model to the real world are the key to paving accuracy.
20 Steering Control Sensor Touches Inside of String Stringline Elevation Sensor Touches Top or Bottom of String Grade Stake Stake Sensors for Controlling Machine Elevation and Position.
21 Sensors Require Hand Tuning to Get Accurate and Smooth Paving Results Sensors for Controlling Machine Elevation and Position.
22 Stringlines represent the pavement using a series of cords. The cords are easy to see in this curve even with a close staking interval.
23 These cords are built into the pavement, as can be seen here with cords in a horizontal curve.
24 Smooth Curve Stringless technology represents the pavement using mathematical equations representing tangents and curves (a true profile).
25 Eliminates cords in vertical curves. Eliminates stringline factors affecting smoothness: o o o o o Sag (stringline expansion in hot weather). Push up (improperly tensioned sensors). Deviations from loss of contact. Bumps from knots/splices. Crew fidgeting with sensor controls. Sensor Follows Sagging String Sensor Looses Contact Sensor Pulls String if Not Properly Tensioned
26 Quality and Process Control Benefits with Stringless More precise machine control (digital) to much smaller increments. Better and more consistent ride quality. Control over material quantities and costs. Lower yield loss. Control of horizontal and vertical curves is significantly more accurate to the plan arcs are paved versus a series of cords!
27 Stringless control of thick airport paving.
28 What s Required to Transition to Stringless? Contractor: Capital expenditures. Investment in control (control points). Understanding line-of-sight for instruments. Understanding weather and environmental considerations for total stations, lasers and GPS. Learning curve/training dedication of trained personnel to run stringless operation and work with 3D model.
29 What s Required to Transition to Stringless? Owner/Agency: Acceptance allow its use. Adopt end-result mindset (specifications) for thickness, smoothness. Provide (or validate) control points. Provide plans and CAD files to contractor for use in creating 3D model. Learning curve/training for field inspection or construction management staff.
30 Salt Palace Convention Center Title: Technology Advancements in the Field: Stringless Paving Speaker: Chad Ackley, P.E., CHA Consulting, Inc. Date: March 2, 2016
31 Introduction Stringless technology/automatic grade control from the design engineer s perspective Review of recent runway rehabilitation at Myrtle Beach International Airport using this technology Lessons learned Look ahead
32 MYR Runway 18/36 Rehabilitation March 2-4, 2016
33 MYR Project Overview March 2-4, 2016 Single runway airport (9,500 feet x 150 feet) 12 taxiway connectors Former USAF base Multiple pavement sections (asphalt and PCC); runway extended twice since original construction PCC ends structurally deficient for A320 and A321 Non-standard longitudinal and transverse gradients
35 MYR Project Overview Tourism major component of the local economy Off-season and off-peak construction September, 2014 to March, 2015 Night work only Weeknights: 10:45 PM 6:45 AM Weekends: 11:45 PM 5:30 AM Runway open to traffic during the day P Weather Limitations Surface temperature of underlying course (45 degrees F) Wilmington, NC terminal stopped shipping PG binder for the surface course (too stiff to pipe in cold temps)
36 MYR Project Overview This job demanded speed and efficiency Stringless paving was key! ( else we may still be paving )
37 Design Considerations March 2-4, 2016 Five surfaces Existing Surface Milled Surface 1 st Lift Surface 2 nd Lift Surface Finished Surface What s the best way to present the information to the contractor? Contractors want the digital design files Release disclaimer
38 Design Considerations Contractor imported our design elevations from MS Excel into their Carlson Takeoff Suite software We were able to compare each surface before construction started Makes it easier on contractor, but ensures correct transfer of data
39 Design Considerations As-built final surface compared very well to design surface; no payment adjustments
40 Lessons Learned March 2-4, 2016 Night construction = terrible project photos Temporary pavement markings Saved time each night by outlining using Polaris Brutus with spray can mounted to machine control equipment
41 Lessons Learned March 2-4, 2016 Expand the survey area Automatic grade control equipment doesn t like being near the edges of the survey data Contractor recommended feet of additional survey beyond the limits of construction AutoCAD drawings presentation vs. functionality Annotated/blocked/hatched features in AutoCAD do not show up on machine control equipment in the field Redraw symbols (to scale) using polylines
42 Going Forward AE firms: is our product transitioning away from paper plans to the digital design model? Where do project digital files (*.xml, etc.) fit into the discrepancy chain?
43 Going Forward March 2-4, 2016 How does your QA/QC reviewer check a digital file? Where to focus design efforts in plan production? Paper Digital How will that work with FAA specs like P-152 (cross sections)? When do we distribute the digital files? After contract award During bidding?
44 Going Forward March 2-4, 2016 Automatic grade control equipment is here to stay As design engineers, we need to learn out to handle this technology advance practically, professionally, legally and within our E&O guidelines
45 Salt Palace Convention Center Title: TECHNOLOGY ADVANCEMENTS IN THE FIELD STRINGLESS PAVING Speaker: Robbie Pope, PE at GOMACO Corp Date: March 2, 2016
46 Presentation Outline What is 3D stringless paving? Benefits of using 3DMC. What technology is currently in the market? Why are contractors moving away from traditional paving methods? What infrastructure does a contractor need in place to implement stringless technology? What happens once the 3D technology is purchased and in place? Workflow of Stringless Paving
47 What is 3D Stringless Paving? March 2-4, 2016 Question: Answer: Question: Answer: What is Stringless Paving? A 3D Machine Control system that simplifies jobsite logistics, reduces costs and improves quality and safety How does it work? It uses a variety of sensors and surveying instruments to monitor your machine s real-time positions compared to a digital model to automatically control the movements of steering and elevation.
48 What is 3D Stringless Paving? In short it removes the guidelines that traditionally run the length of the jobsite and replaces that with survey instruments and a virtual stringline.
49 What is 3D Stringless Paving? March 2-4, 2016 A Brief History of Stringless Paving First machine automated tests using total stations occurred in Germany in First construction application was high speed railway paved in Germany in First road in USA both graded and paved without stringlines was on Sept in Ida Grove Iowa. Stringless Use on Airports Military Civil RAF/USAF Fairford (UK); USAF Kirtland (NM, USA); USAF Lakenheath (UK); Belle Chasse Naval Reserve New Orleans, LO (USA); Homer Regional Airport, LO (USA); Travis USAF Cal USA; El Centro Cal, USA; Virgin Galactic Spaceport, New Mexico; Jacksonville USAF, Florida; Tulsa Air National Guard, Oklahoma; Zurich & Basel International (Switzerland); London Heathrow & Stansted, Edinburgh Intl., Farnborough, Luton Intl. (UK); Paris Charles de Gaulle (France); Atlanta Hartsfield Jackson Intl., Baton Rouge; St Louis, Missouri; Indianapolis, Indiana; Toulouse (France); Chicago O Hare; Guadeloupe (Caribbean); Paris Orly (France); Charlotte, NC, USA; JFK Airport, New York, USA; Fort Lauderdale-Hollywood, Florida, Dallas Love Field; BWI, Baltimore International
50 What is 3D Stringless Paving? Partial List of North American use of Stringless Paving Projects State Company Project NY Coldsprings, Surianello, Tutor Perini 90, JFK MI Toebe, AJAX 196, 75, 10, DTW PA Golden Triangle WV Hiway paving MD Cherry Hill Construction Andrews AFB IN Primco, Milestone, Walsh, FWI 69,31,24,IND IL Walsh, D's construction, MCI, ET Simonds 80,74,57,94,ORD KY Harper 416 WI Walsh 94 MO FWI, Millstone Bangert STL, 70, 270 AR Weaver Baily, Harper XNA Airport (NW Arkansas) TX MCM, HRT JV, Texas Sterling, Granite, Lonestar,Kiewit DAL, HRT, City streets in Lubbock, 26, 114, 635, Burleson (NTTA Chisholm Trail) GA Scruggs, MCI, APAC, Kiewit 75, ATL, 85, 92 SC Zachary, MCI, Lane 385, AFB in Charleston, 20 NC Hiway Paving, Zachary, Lane, Archer Western/Walsh Raleigh Durham toll road, CLT, Apex VA Hiway Paving FL Pepper, Kiewit, Archer Western, Head Inc Jacksonville AFB, FLL Airport, 95 LA Kiewit AFB OK Head inc. Tulsa Air National Guard KS Ideker Highway 24 NE Paulsen, Hawkins US-35, US-30, I-80, City streets IA Manatts, MCI, Flynn, Croell, MFT I-80, I-29, 680, I-35, HWY-20, 380, DSM, OMA, ALO, multiple county roads CO Kiewit NM Montoya Space port, 64 AZ Southwest, RL Wadsworth, Kiewit/Sundt 101 UT Provo River constructors JV, RL Wadsworth, Wadsworth Brothers Orem I-15, Logan US-10 ID CPC OR CPC CA Baldi Brothers, CC Meyers El Centro AFB, Travis AFB, 132, 4 NV Southwest Reno HI Baldi Brothers AFB Hawaii TN APAC Memphis Airport Alberta Flatiron Ontario Coco, O'leary 402 Quebec EBC Mexico Cemex
51 Benefits of using 3DMC A 3DMC system simplifies jobsite logistics, reduces costs, improves quality and safety Removes stringlines and pins from the jobsite Removes installation, maintenance & removal costs Increases work safety, especially at night Removes down time from stringline breaks/bumps during production Puts the 3D job design directly onto the machine Eliminates survey setup errors in stringline influences No waiting for setting-out before production No dependency on setup work wherever you have 3D data Increases productivity, quality and performance bonuses Controls height, slope (and steer) of machines Delivers a precisely-constructed product Optimises amount of new material needed Reduces over-trimming/milling, overpouring Improves concrete yields and material cost savings
52 Benefits of using 3DMC Logistical Advantages During and After Construction Roadway is now open Trucks no longer need to back up so far No Gates in wireline needed Better versatility moving through site No lost time to tear down of wireline Wireline Clearance Track grade now only needs to be the width of the actual machine profile, allowing this technology to be used in much tighter spaces and confined areas.
53 Technology in Market Today All 3 major developers of survey instruments have 3D Slip-Form Paving solutions.
54 Technology in Market Today Overview of the instrument technology types offered and their applications Total Station accuracy +/ *line of sight Millimeter GPS accuracy +/-0.01 *with good satellite signal GPS RTK accuracy +/-0.1 *with good satellite signal Slipform Pavers Trimmers Milling Machines Curb & Gutter Asphalt paving Slipform Pavers Trimmers Milling Machines Curb & Gutter Asphalt paving Slipform Paver** Placer/Spreaders Follow-up Machines Curb & Gutter Steering Asphalt Paving Steering **used only in mixed modes with other sensors on fill-in lanes
55 Technology in Market Today March 2-4, 2016 There are many different sensor choices and many different applications for each sensor VS TPS SO Choose your sensors wisely! GPS
56 Technology in Market Today
57 Why Contractors use it? Because stringlines are expensive, time-consuming and error-prone to install are easily damaged before and during paving are easily misaligned (errors increase costs) are a significant site safety hazard interfere with site logistics, increase concrete delivery time, haul costs, and reduce productivity. greatly increase pre-production planning & surveyors workload
58 Why Contractors use it? Advantages the paving contractors are seeing in implementing 3DMC Good site engineers/surveyors are hard to find, and expensive Stringlines don t always model the concrete design accurately Go in, pave & get out ability minimizes machine standing time ideal for time-critical paving operations (e.g. live airports, roads) Estimated 50% survey cost reduction - one surveyor or engineer manages the 3D system Estimated 20% productivity increase (up to 50% in complex areas) Direct construction from CAD design no intermediate rework One 3D model for trimming and paving = material cost savings
59 Contractor Infrastructure Required
60 Components Leica PaveSmart Contractor Infrastructure Required 3D Sensors Total Stations 1 accuracy total station Fully robotic operation Automatic prism tracking Simple setup and position fix Can be used for any surveying tasks 10-12Hz measurement rate Backlight & heater for night operation Typical working Range ± 300ft Tracking accuracy ±0.01 at 300ft
61 Contractor Infrastructure Required 3D Sensors GPS (for machine steer option only) Machine GPS Components Leica PaveSmart Supports GPS & GLONASS systems for maximum operational time Simple setup and position fix routine Identical user interface to TPS no extra training required Can be quickly removed from machine and used for any site surveying tasks True 20Hz measurement rate Typical Tracking Accuracy: Position ±0.03FT Height ±0.06FT
62 Contractor Infrastructure Required 360⁰ Prism Radios Machine Computer 360⁰ Prism Survey Control Point Slope Sensor Slope Sensor Total Station #1 (Guidance) Survey Control Point Total Station #3 (As-builts) Total Station #2 (Guidance)
63 Contractor Infrastructure Required PZL-1 (Positioning Zone Laser) Transmits Unique Laser Zone Signal 500 Foot Diameter Auto-Leveling 4 Channel Operation Alkaline Batteries, NiMH Rechargeable, & External Power mmgps Machine Sensor 3DMC User Interface Used in 2D & 3D applications Touch screen Windows XP Operator selectable views mmgps Transmitter PZS-MC (Positioning Zone Sensor for Machine Control) Receives & Decodes the Laser Zone Signal 360 o beam Detection Rugged, Shockproof Design IPX6 Waterproof DC8V~DC32V Power Supply GX-60
64 Contractor Infrastructure Required Total Station Option GX-60 Display LCD Color Touchscreen Machine Prism integrated GPS+ antenna Machine Radio Long range Bluetooth PS-101 Total Station 1 (arc-second) resolution +/- 3mm at 100m Fully Robotic
65 Contractor Infrastructure Required March 2-4, 2016 Trimble PCS900 Consists of: CB460 Display Color screen SPS930 Total Stations 1 accuracy +/- 3mm at 100m Machine Radio MT900 Active Prism MS992 GPS Receiver Head Dual-Axis Angle / IMU Sensor
66 Now what do we do with it? We just bought all this stuff and nobody knows how to use it!! Tips for Successful Implementation Contractor Buy-In Training Provided by vendors on customer jobsites around the world Experience Many field procedures are new compared to using string It is a repetitive skill but the learning curve is not steep Adoption Field crews must fully adopt to be successful Role changes Added responsibilities for foreman/groundman 3DMC interface replaces wands for making real-time steering and grade changes Replace stringline crew with Field Tech Crew member dedicated to setting up survey instruments and QC checks Data Prep - may be done in-house or contracted out Equipment and Training up to date Market is frequently changing/updating and releasing new products
67 Now what do we do with it? We just bought all this stuff and nobody knows how to use it!! How can the owner/agent get involved in the construction process? Tips for Successful Implementation Agency Buy-In Knowledge A basic understanding of the process Quality Control (includes both before and after pave) Check sub-grade before paving Verify digital model before paving Field Verification Obtain their own survey instruments for QA/CQ Use Contractors instruments for QA/QC Additional tools Utilize other tools such as real-time smoothness indicators and auto-survey & as-built functions
68 Workflow of Stringless Before you order the Concrete Trucks! Preferable Pre project check list! 1) Establish Control FIRST! 2) Maintain control network and have quality check continuously throughout the entire time frame of the project! 3) Know or define where the existing project (roadway) is today X,Y,Z 4) Know where the proposed project will be upon completion (model of proposed) Your yield is at stake! 5) Do a quality check BEFORE you pave! (i.e. dry run the machine) 6) Make corrective actions to the surface prior to paving if necessary!
69 Workflow of Stringless Working with Stringline Inspect design calculate setting-out lists for each lane Setup a total station, 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 Reference Point Check pin alignment & adjust if required Survey and set stringline height on each pin (min. 2 men) Install & tension clamps and stringlines Walk left 5ft! Walk right 1ft! Up a bit! Down a bit! STOP! 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 Stringless Paving vs Wire
70 Workflow of Stringless March 2-4, 2016 Data Prep is Crucial Don t let it scare you the 3D model is simply a digital representation of the stringline The virtual stringline model now becomes one of the most important aspects of paving The success of accurately and smoothly paving depends on the quality of the digital model How do we model the paving? Built from Alignment Data, Profile Data, and Template Data Built from Horizontal and Vertical Curves Built from Station, Offset, and Elevation Will the Owner/Agent/Designer provide this data? Paving Models vs. Grading Models Grading model are typically for use with GPS guided machine accuracy required ~ 0.1ft Grading models are surface based and 2D linework is only for reference Paving models are for Total Stations or Lasers accuracy required ~ 0.01ft Paving models are based on alignments (means paver steering is also automated)
71 Workflow of Stringless Design software has different tools for creating 3D Data These packages are used by designers from all aspects of Owner/Agents These packages below export generic formats that the manufacturer software can recognize Linework =.DXF Surface=.XML Alignment Models=.XML
72 Surface Model Quality Assessment
73 Workflow of Stringless Basic steps in prediction analysis on 3D model An example of how to preview theoretical smoothness of a 3D model Open digital model in CAD software Sample from 3D Polyline/Surface Build Profile Sample from Profile Isolate data for ProVal Create a Project Add data from model Run ride quality and/or smoothness quality Make adjustments if necessary and run the check again
74 Workflow of Stringless Quality analysis is more than just a overall number Look closer at the data to analyze for problem areas, specifically bridge ties, transitions into existing pavements and joint matching Overall the 3D Model looked reasonably good IRI less than 30 A closer look at the numbers in the continuous analysis shows problem areas where grinding may occur. Learn to use the different ProVal tools effectively so that we can better analyze our 3D models
75 Workflow of Stringless March 2-4, 2016 Why? Calibration Why and when to Calibrate? Precise paving Optimal machine performance Optimal concrete thickness & cost savings Prism locations, relative to Mould Origin, must be determined Slope sensors must be accurately adjusted (relative to machine & each other!) When? At first installation (commissioning) At EVERY subsequent change of the machine (width change, disassembly/reassembly) Risks if ignored? Mis-matched slope sensors can cause machine twisting Poor concrete surface finish Risk of structural damage to machine (leg barrels, tracks are stressed) jumpy machine Machine will not pave at correct elevation or position
76 Workflow of Stringless Practical Issues In the field! How do we know what is going on without seeing the stringlines? How do we know where we are in reference to the model? What is the contractor doing to verify placement? How does the Owner/Agent get involved in the Quality Process?
77 Workflow of Stringless March 2-4, 2016 Field Adjusting the Machine on the fly Real-time steering and grade adjustments are easy If position needs horizontal adjusting just like stringline control we can adjust position at front and rear independently, without stopping the paver If the level needs vertical adjusting just like stringline control we can adjust all leg heights, and draft independently, without stopping paving Digital Offsets, no hand cranking and forgetting
78 Workflow of Stringless Practical Issues Moving the Robots ( Leapfrogging ) Maximum Range Robot-to-Paver is <= 300FT (*depends on conditions) We don t need to stop the paver all done on the fly Before maximum range is reached, move 3 rd Robot to new position & setup (Position & Orientation Fix). Press Swap Robot on computer System switches control from #2 (or #1) to #3 Robot automatically Move old Robot to new position, setup and repeat procedure Ensure enough Reference Points visible for Setup (Position & Orientation Fix) * temperature, humidity, air quality
79 Leapfrogging Part 1 All Theodolites in Start Position Workflow of Stringless TS #1 TS #2 TS #3
80 Workflow of Stringless Leapfrogging Part 2 Move Theodolite #3 ahead, Setup, Transfer Control (#2-#3) ` TS #1 TS #3 TS #2
81 Workflow of Stringless Leapfrogging Part 3 Move Theodolite #2 ahead, Setup, Transfer Control (#1-#2) TS #2 TS #1 TS #3
82 Workflow of Stringless Leapfrogging Part 4 Move Theodolite #2 ahead, Setup, Transfer Control (#3-#1) TS #2 TS #1 TS #3
83 Salt Palace Convention Center Please feel free to contact me at ay time by any of the listed means below: Robbie Pope, PE GOMACO Corporation 3D Controls Engineer (712) Cell