ASTM E2415-2005(2018) Standard Practice for Installing Piezoelectric Highway Traffic Sensors.pdf

1、Designation: E2415 05 (Reapproved 2018)Standard Practice forInstalling Piezoelectric Highway Traffic Sensors1This standard is issued under the fixed designation E2415; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las

2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the installation of piezoelectrictire-force sensors that are used to detect axles when counting,clas

3、sifying, or weighing vehicles as part of a roadway trafficmonitoring program. Piezoelectric sensors are often used inpairs and combined with other roadway sensors such asinductive loops to classify and weigh vehicles.1.2 The practice applies only to piezoelectric tire-forcesensors used for the detec

4、tion of vehicle axles on a roadway.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are for informa-tion only and are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its u

5、se. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principl

6、es on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E867 Terminology Relating to Vehicl

7、e-Pavement SystemsE1318 Specification for Highway Weigh-In-Motion (WIM)Systems with User Requirements and Test MethodsE1442 Practice for Highway-Traffic Monitoring (Withdrawn2001)3E1572 Practice for Classifying Highway Vehicles fromKnown Axle Count and Spacing (Withdrawn 2002)3E1957 Practice for Ins

8、talling and Using Pneumatic TubesWith Roadway Traffic Counters and Classifiers3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 axleaxis oriented transversely to the nominal direc-tion of vehicle motion and extending the full width of thevehicle, about which the wheels at both e

9、nds rotate.3.1.2 axle countnumber of vehicle axles that are enumer-ated at a point on a lane or roadway during a specified timeinterval.3.1.3 axle countera device that receives signals from anaxle sensor and indicates the cumulative number of axles thathave been detected by the sensor during a speci

10、fied timeinterval.3.1.4 axle spacinghorizontal distance between the centerof a vehicle axle and that of the preceding axle on the vehicle.3.1.5 machine countcumulative number of axles,vehicles, or vehicles within specified classes, or all of these,indicated or recorded by a traffic recording device

11、for aspecified time interval.3.1.6 traffc counterdevice that indicates, and usuallyrecords, the number of vehicles or vehicle axles, or both, thatpass a point on a lane or roadway during a specified timeinterval.3.1.7 traffc recording deviceunit that receives outputfrom a sensor(s) and registers axl

12、e count, vehicle count, vehicleclassification count, speed, gap, or headway (any or all ofthese) for defined time intervals.3.1.7.1 DiscussionA traffic recording device may alsorecord axle load and gross vehicle weight. Refer to Specifica-tion E1318.3.1.8 vehicleone or multiple mobile unit(s) design

13、ed fortravel upon a roadway; a vehicle comprises one powered unitand may include one or more non-powered trailer or semitrailerunit(s).3.1.9 vehicle classification countcumulative number ofvehicles of each defined type (class) indicated or recorded fora specified time interval.1This practice is unde

14、r the jurisdiction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.52 onTraffic Monitoring.Current edition approved Sept. 1, 2018. Published September 2018. Originallyapproved in 2005. Last previous edition approved in 2012 as E2415 05 (2012).D

15、OI: 10.1520/E2415-05R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this hi

16、storical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Dec

17、ision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Summary of Practice4.1 Site Selection:4.1.1 Select a relatively straight and smooth section ofroadway that is expected

18、to have free-flowing traffic through-out the duration of the data collection session.4.1.2 The selected roadway section should have little to nosurface distortion or rutting in the wheel paths.4.1.3 Longitudinal grades and lateral pavement slopesshould be less than 3 % as per Specification E1318.4.1

19、.4 The selected site should have:4.1.4.1 Access to electrical power or good location for solarand telephone service if data is to be collected continuously formore than a few weeks at a time,4.1.4.2 Adequate space for an instrument cabinet, with asafe area for a technician to park a vehicle and stan

20、d whilemaking adjustments or repairs, and4.1.4.3 Adequate drainage to prevent standing water insplice boxes and instrument cabinet.4.1.5 Traffic conditions at the site should include minimaloccurrences of stop-and-go traffic, slow-moving traffic, lanechanging, and passing on two-lane roads.4.1.6 Pav

21、ement cracks and joints shall be avoided. Do notplace a sensor across any crack or joint. Whenever practicable,space sensors a minimum of 1 ft (300 mm) from transversecracks and contraction joints and 6 ft (1800 mm) fromexpansion joints.4.1.7 Pavement thickness and strength must be adequate tosustai

22、n the additional stress concentrations that will result frominstallation of piezoelectric and other associated sensors.4.1.8 Site requirements for installing weigh-in-motion(WIM) systems are given in Specification E1318.4.2 Installation Procedures:4.2.1 Installation should be performed in relatively

23、 goodweather, avoiding extreme heat or cold and moisture conditionsthat might adversely affect the bonding of grout to the sensoror the pavement.4.2.2 At the selected site, use a taut string line or a templateoriented perpendicular to the flow of vehicular traffic to markthe sensor locations.4.2.2.1

24、 Colored spray paint applied over the string line ortemplate will provide a more lasting guide for pavementcutting than chalk or crayon.4.2.3 Use a pavement saw or similar equipment with acompetent operator to make the necessary parallel cuts in thepavement.4.2.3.1 The width and depth of the cut sha

25、ll be in accor-dance with the recommendations of the manufacturer of thesensor.4.2.3.2 When feasible, use a saw blade of proper thicknessor gang several thinner blades together to cut the sensor slot inone pass. If two cuts are made for installation, use a hammerand chisel or a small jackhammer to l

26、oosen and clean out allmaterial between the two cuts to the required depth.4.2.3.3 Wash the slot and adjacent surface with clean water,using a high-pressure washer. Ensure that no contaminatedwash water remains in the slot. Dry the slot and adjacent roadsurface using compressed air and a blowgun. Th

27、e air compres-sor should have a dedicated outlet for the hose and be able tosustain a minimum flow rate of approximately 185 ft3/min(5 m3/min). An air drier/oil remover unit should be installed atthe compressor outlet. Use a dedicated 50-ft (15-m) section ofairline hose for this process. Make sure t

28、hat all dirt andmoisture is removed from the hose before use.4.2.3.4 Inspect the slot, and use a wire brush or a chisel todislodge any debris that may still be clinging to its sides andbottom. Again, use compressed air to remove any remainingdebris from the slot.4.2.3.5 After unpacking any type of p

29、iezoelectric sensoronsite, test its output signal according to the manufacturersinstructions, making sure the sensor is working properly.4.2.3.6 Test slot length, depth, and width by lowering thesensor or an accurate template into the slot and look for contactpoints on the ends, bottom, and sides of

30、 the slot.Adjust the sizeas needed.4.2.4 When cutting slots for lead-in wire runs to the edge ofthe pavement, including the paved shoulder, make every effortto avoid unnecessary horizontal angles and turns.4.2.5 It is recommended that the sensor lead-in wires be ofsufficient length to reach into the

31、 equipment cabinet withoutsplicing. When a splice must be made, use an approvedunderground wiresplice encapsulation kit in accordance withthe kit manufacturers instructions. This helps ensure thatmoisture will not enter the wire and render the piezoelectricsensor unusable until the splice is replace

32、d. Splices should behoused only in junction and splice boxes. Splices should bestructurally strong, electrically sound, and waterproof. Splicinggenerally requires a well-trained, certified electrician. He orshe shall follow the manufacturers instructions or standardprocedures carefully and exactly.4

33、.2.6 Cover the pavement surface along both sides of theslot with a 3-in. (75-mm) wide strip of gaffers tape or ducttape.4.2.7 It is extremely important to always handle the sensorcarefully. When installing bare (not encapsulated) sensors,never handle the sensor without new, powder-free vinyl orlatex

34、 examination gloves. This keeps the oil from ones handsfrom contaminating the exposed surface of the sensor. Thelead-in wire is especially vulnerable to being pulled away fromthe sensor element inside. Never bend the sensor so as to breakit or so as to form a kink in it.4.2.8 The exposed surfaces of

35、 a bare sensor should be“roughed up” using a medium-grade emery cloth or sandpaper.4.2.9 Clean the exposed surfaces of a bare sensor of any dirtor oily substance with acetone, denatured alcohol, or othersimilar zero-residue solvent that will not harm the surface orthe lead-in wire insulation and wil

36、l not interfere with theadhering properties of the selected grout.4.2.10 Use a grout recommended by the sensormanufacturer, or one specifically approved by the sensor user,that will adhere well to the sensor and pavement material andwhich will cure quickly so as not to delay traffic at the sitedurin

37、g installation. Many grout problems stem from incorrectproportions, improper mixing, or entraining air during themixing process. Consideration may be given to using adual-canister pneumatic applicator that combines both groutE2415 05 (2018)2components in an exact mix during the application process,t

38、hereby reducing errors commonly experienced with handmixing.4.2.11 Prior to mixing grout or beginning grout application,test the sensor output signal again according to the manufac-turers instructions, making sure that the sensor is workingproperly.4.2.12 Prepare, handle, and finish the grout in acc

39、ordancewith the recommendations of the sensor manufacturer.4.2.13 Use grouting procedures recommended by the manu-facturer to ensure that air voids are not present. Higher-viscosity grouts are more likely to trap air under the sensor.4.2.14 Following the instructions of the manufacturer, placethe se

40、nsor in the pavement slot, adjusting its height so that thetop of the sensor is positioned according to the manufacturersspecifications. This is usually accomplished by using bracketsand/or jigs to hold the sensor at the correct height.4.2.15 With the sensor correctly held in place, carefully fillth

41、e pavement slot with grout.4.2.16 For a bare sensor, use a putty knife, trowel, or similartool to smooth the grout so that it is flush or just above the roadsurface. The top of the finished grout surface shall not be belowthe road surface. It is better to leave too much grout and grindthe excess awa

42、y after it has fully cured than to leave adepression in the roadway that will degrade the sensor signal.4.2.17 When the grout has partially cured, carefully removethe tape and any additional fixtures from the adjacent pavementsurface.4.2.18 It may be necessary to use an angle or belt grinder tofinis

43、h the grout so that it is flush with the road surface. Ensurethat the grout is fully cured prior to grinding and to opening thelane to traffic.4.2.19 Route the lead-in wires through the sawn lead-inslots and conduit to the equipment cabinet or to the splice box,making sure not to kink or nick the ou

44、ter protective insulation(see 4.2.5). Use additional grout or sealant to fill lead wire slotscompletely to edge of pavement.4.2.20 With the sensor and lead-in wires in place, test theoutput signal at the cabinet according to the manufacturersinstructions, making sure that the sensor is working prope

45、rly.4.3 Post-Installation Testing:4.3.1 Use an oscilloscope to observe the piezoelectric sen-sor output signal for proper signal strength, good signal-to-noise ratio, and clean pulses when vehicles pass over thesensor.4.3.2 For applications other than weigh-in-motion, once thepiezoelectric sensor(s)

46、 have been installed and connected to asuitable traffic recording device, a verification count must bemade to determine whether the sensor output signals are beingrecorded correctly. There should be a mix of vehicles, includ-ing those with light, medium, and heavy axle loads that willnormally pass o

47、ver the sensor(s).4.3.3 To make the verification (machine) count, initializethe traffic recording device (that is, note the indicated axlecount) and then concurrently have one or more persons countand record manually (manual or validation count) the numberof axles that pass over the sensor(s) until

48、at least 50 axles havepassed. After this, note the indicated machine count (verifica-tion count) on the traffic recording device and calculate thenumber of axles counted concurrently with the manual count.Compare the machine count with the manual count(s) (valida-tion count(s) to verify that the axl

49、e counts were determinedcorrectly. If more than one person made a manual count, thereshall be no more than 2 % difference from the largest value forany count to be acceptable for use in determining the validationcount. Repeat the manual counts (and the machine countsconcurrently) as necessary until this condition is satisfied; thencalculate the mean value of all manual counts and round themean value to the nearest integer. Use this integer value as thevalidation count. For acceptable performance, the machine(verification) count should not vary from the validatio