Chapters 5 and 6 by ca40a98986880297


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provided road

for each 1.5 urban complex interchanges, two urban The ruck requirements or four rural interchanges. section by the equation: are calculated

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A 1.5 2 2.5 trucksD


r number distance

to be plowed miles15 cyle time N- the

in lane plowing N N speed and in C


in hoursN. number of

complex simple (B)cur course, (u) and rural r urban (r) guidelines any equipment interhanges.Of must be

(A) and

adapted within of each unit or road section an for the particularneeds organization. Past experi¬ence boh ith the in each road section, durabilty the productivity, or the equipentand has large influence with in determinng types, and the particular thenumbers, sizes, manufaturer past experience can be of the variousequipments Much of this based variousmanagement systems, such as how long it upon the reporting takes of work, given piece or the a driver tocomplete his maintenance on piece record particu¬lar equipment requirements of equipment.When are being established due to the contractors who may consideration mustbe given use of outside have equipment during avail¬able months for augmentation the winter of the fleet ofequipment in a given existing jurisdiction When equipment needs cost total point of view (taking nto account are examinedfrom year-round and laborrequrements equipment deprecaton maintenance garaging find require¬ments), that many organizations outside, rented contractor operators and oftentimes a equipment(with supervisors) provides to the winter primary maintenance problem.The thrut cot-effectivesolution of any winter maintenance program should be effectively to utilizeall equipment yet, at the same time not abuse it. Each organ¬ization to most effective equipment to should strive use its its maximumcapacity times and lesser at all to supplement its use with capacityequipment This as required heavy storm periods. during heavy-duty, equipment and first-line with ground-speed controllers, (preaders trucks should large front-end plows and wing plows) with scrapers, alwaysbe mantained condition.69 in top working

Labor RequirementsSpecific for a given road section are a function manpower requirements ofthe equipment and large number of other local requrements variables.General that practices have evolved concerning what constitutes one-manand two-man operations The practices however. of are worth noting, theState cited of Minnesota Department of Highways are the examples hereVehicle operation by one man is weather single does and road such in permissible:• conditions as sanding large windrows Whenever a permit or safe operation;• For operations not result chemical application;• When on traveedsurfaces.Two-man


operation is used:• vehicles due to For that blowing


poor visibility snow may affect safeoperation;•


large windrows requiring more thanone operation to traveled portio of roadway;• On certain hazardous the extensive plow; left-turn or• Any slots;• For operations


roadways with use of considered operations normalized under

involving a wing other operation oneand two-man are used when they are safe andtraffic so that operations are less restrictedThe arrangement are as follows;• Removal this conditions have types of work performed of snow from space for the

unsafe for

one operator.Combined

shoulders ad adjaent provideadditional slopes to next storm;• Removal of snow from and visibility;• intersections banks other loations wherehigh Resumption normal of and• Performance traffic maintenance of any to



operations; that will return


operation normal.Equipment

ReliabilityCareful attention should

of all be paid to routine maintenance equipmentand especially the first-line which is crucial program. The to the winteroperations equipment equipment program should focus on70 maintenance

it is equipment minimizing downtime so that for the first-line availableduring the time of greatest Such a maintenance program need. requiresthat the ummer and fall routine overhauls be completed during months,that at the locationwhere be stokpiled key components of the equipment are availablewho the aintenance personnel it might be needed and that can, by all means withi their capability, get key piees of equipmentin operation in the event of breakdowns.TRUCKSTruks

programs. are the bakbone of all snow and ice control and/or spreading chemicals and abrasives, they come in depending from small upon heir use. They range plows to tractor-trailer rigs for chemical/abrasive of a truck is of road. The choice stretches intended year-round purpose, by its which can result than optimal snow for and ice control.The five-ton

Used forplowing sizesand all capacites four-wheeldrive utility long, spreadingon straight oftencontrolled in equipmentthat is less

of two-axle heavyduty truk shown in Figure 15 is the overwhelmingchoice all truk for thitype of snow and ice control organizations. Specifications 6. Ideally summarized in Table for snow and ice controlthis type of are truck with spreader and a is equipped hassis-mounted plowor combination of rated plows. The hassis-mounted spreader makes fuller useof the capacity with dump body spreader. than does a truck and aslip-in Chassismounted however, in the spreaders, require dismountingof the spreader spring and replacement advantages with a dump body for summeroperationsThe of equipping such a truck with a dump body and a slip-intype are two-fold spreader changing over of spreaderbodies is eliminated, and, annual The twice through the the use of a storagerack, slip-in spreader suitably designed snow, can be removed during those periods there is little in the winterwhen and the trucks can be used for other disadvantage operations.A of the slip-in type spreader is that of the it does not make fulluse of the capacity truck. Because the tare weight the truck,dump body, and empty spreader of than that andchassis-mounted spreader, of the truck is greaer less capacity is available for material given gross vehicle fora weight. the center gravity Additionally, of aloaded slip-in of spreader is higher than that spreader.A solution to this for a chassis-mounted problem is the use in of a type spreader conjunctionwith dump body.Many organizations utilize lighter-duty trucks of from 2-ton to 3-ton capacityfor plowing operations. These trucks are seldom equipped spreaders with andare often maintenance used for other e.g., operations, as sanitation sign and truks,for landscape work, during lane marker pantng andfor operations, general utility Specifiations work. medum-duty for this truck 6.The versatile areshown in Table fourwheel-drive three-quarter ton pickup truk is beingused a twoway power anglingplow, it as in service areas71 suh inreasingly is useful for for plowing. plowing in Equipped with tight areas,

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and is sometimes even used for main-lineoperations. is shown in Figure set up for plowing 16;the a vehicle are shown in Table 6.In is equippedwith ruck a small ton pickup some organizations, three-quarter Often 17. used by the foremenfor 1.5-yd spreader as shown in Figure for quick application of hemicals patrol, are useful these units asneeded and, often breakdown, when larger spreaders for backup.Each rest on turnpikes, A typical unit specifications for such areas truck should be equipped with lights and other and federal with all state regulations. include:• chassis delinetion flashing alternately comers of the lights,• light a revolving mounted on the top of the cap,• two safety As a equipment inaccordance minium theseshould

mounted near the flashing warning lights topextreme hopper or on the a chassis-mounted of upperextreme a back end of a dump body,• that aimed clear at the the tip front-end of any set plow,• wing plow a to fixed beattached,•

of headlights spotlight

reflector flare and aid kit,•



two-way radio,• chocks lights,• • wheel cab map

flood light discharge rear view area, and• two

on spreader outidemounted




advent be of the current shortages, more careshould fuel and material to the selection and specification and theircomponents. given of trucks increase almostmandatory in trucks costs make the The sharp in fuel and above soft the class. Certainly, tougher paints and optional whenever be speifiedfor primers all should and municipal equipment state favors trucks the possible. The lower milegetime of municipal usage ratio components.Choice and other selection of fiberglasscabs non-corrosive of the smallest displacement engine that will do the job effectivelywill automatictransmissions units, coupled74 result are slowly in conued fuel into coming Modem savings. multi-range own. their These


the proper engne training operator

increase can save fuel, time and fatigue.Icreased




complexity emision equipment requiresmore in mandatory aety and maintenance downtime. in order to reduce Coprehensivemaintenance preplanned manuals should when new equipment be specified is procured,especially for components devices the new anti-skid that may beunfamiliar like to maintenance Perhaps training personnl. additional formechanics at the time of purchase should alo be considered. This isalso a very good time to review requirements for spare parts with aneye on the increasing lead time necessary to obtain replacement parts.With increaes in truck costs of predicted years, it or more for the nextfew behooves the buyer to choose trucks maximum and options that willyield service and longevity. In general, this trucks o simplest, means selectiono most rugged designs and maintained,SPREADERSSow and ice that are most eaily control programs that use granular cheical and/or abrasivesrequire these materal on the roadway within closelycontrolled several techniques.Earlier when sand, cinders, a means of applying areas. There are

and/or salt of a were used, a laborer (sometimes two)stading near the bak of dump truck would fling preading materialin over the bac end pattern of slowlyproceeded down Later, the truc the highway. as rock a the driver came into more generaluse, salt installed large some organizations which discharged left rear funnel on top of a tube, behind the alt wheel into Saltscooped the funnel by laborer was discharged of the truck. out of the tube intoa windrow that rear down behind the left was laid wheel and near the centeror rown of the road. could be drive at a The trucks rate, andconsiderably more road could be higher treated during a storm. the Often truckwas equpped with to protect fro a built-up canvas cover thoserugged the eleents individual who shovelled*Meanwhile, dry fertilizer were being spreaders developed for These to he agricultural deigns were adapted quite naturally the spreading salt and abrasives. The modern outgrowth ofrock spreaders of these is thefocus in this of our attention The most popular basic manual. types generally ofpreaders found in snow and ice control programs are described.By far the most popular type of spreader has which iseither hopper, and has a powered, chain-type into a dump body chassis-mounted or slips and/or abrasives 18.Chemicals in Fiure unit is shown A slip-in conveyor. falldown a chute onto a removed from the hopper by the conveyor roadway. ontothe material the Details spinner which distributes rotating 19. A system of shown inFigure spreader are and of the of the spinner the spnner, patternfrom used to limit the spread flaps is often particularly high-speedroads77 alt on application of for


The Michigan

Department of State Highways has engineered a versailemodification Figure 20. Through basic deig as hown in of this remotecontrol leavig flap in the discharge chute, the endof the of the maerial chain belt can be directed either onto which spiner, gives afullwidth spread pattern, or oto transverse auger which moves thematerial through the tube 20 to an mpeller shown in igure mounted ontoa end of the auger haft. discharges to therear as he This impeller the material truck proceeds forward. matches The rearward velocity of the materialclosely the forward veocity landson the material the road at of the truck; since velocity with respect does not bounceor off the zero slide road, it to the driving lanes. The discharge is on the left-handimpeller scroll pointed dowward approximately has been ten degrees, the dischargeend and modified slightly upnto the air before to enure that materia is ot thrown it lauds the auger, on the road urface. By reversal of thetranverse material end of the can be discharged in a windrow from theoppoite transverse of shown in igure tube 20.An additional feature

the the

spreader used b the Highways is State of MichiganDepartment of lump breaker shown in Figure rotates Thisbreaker as the 21. chain moves, and fingers crush all lumps the before they pass ofthe through the spreader Spreaders screen with 2,5 gate. shouldbe equipped with to 3 inch openings that all on the top of thehopper ensure to material entering through the is of sufficiently small that it will pass sizeso narrower opening conveyor. On large at the dischargeend of the chain-belt spreader units, a pointed over the chain-belt bridgeroof is installed to keep the full from resting conveyor load ofthe alt material or abrasive the chain a hydraulic on belt. it eaier for system to This bridgemakes start oving aterial with whenthe hopper is fully loaded.Spreaders chain-type conveyor belts have gate at a controllable thedischarge the hopper on thechain-belt. leaving of the hopper is usedfor setting offer spreaders, auger-type end to limit the amount of painted on ytem An index the openin of this gate.Some material the back manufacturers

in which a single augerlocated of the hopper conves along the bottom saltto the chute above a distribution spinner. Usually these spreaders areequipped with a separately located driven agitator above the main prevet auger and stopping the aterial from bridging over the auerto flow.Several manufacturer offer a hopper model with a chain-bet conveyorthat achute of the front material out end of the hopper and into discharges that located midwaybetween the to sideways spinner carrie the material to thistype of An advantage and rear axles of the truck. front delivery on discharged infront are abrasive materials salt or is that added tractionparticularly the insuring wheels of the truck, thereby drive unloadsfrom that the spreader advanage is on icy roads. Another the always remainsbetter load the remaining rear and toward the front, distributed and rear beween front wheels of the truck.79





built to he design specification of the Province of Ontariois spreader 22. This spreader has shown in Figure pyramid-shaped hopper with the amount of material in contact with theshortacapacity of 4 yd. Because sidedelivery small the starting is hydraulicsytem chain belt load on the full-length than that in a conveyor.The less chain-belt is considerably type of spreader between the front and rearwheels spinner on this is located of the truck on the driver side, is discharged infront of and material deflector is used to limit drive wheels. the A small thedistribution of material on the road surface.Low Center of Gravity State SpreaderThe Michigan Department spreader has developed of Highways an intersting with double dual augers shown in feature Figure 23 and 24. Theimportant hopper has a type of spreader is that load size,the for a given of this lower enter than does a comparably sized and better of gravity spreader, use is made of existing volume within thetruck. of augers Each pair rotates in opposite at the same speed. and all directions, augersrotate They turn cross auger or spinner as feed a common chute which feedsa in of materialis by the speed of already described. The quantty regulated the and augers located in theexit discharge of the auger.Spreader Towed Behind a Dmp TruckThe spreader unit shown in Figure 25 is towed a mechanism whereby chemicals dup behind truckand provides a standard abrasives are appliedin proportion and/or to the distance which the vehicle in Europe and now finding travels. This unit,developed application is agenuine country ground-speed-controlled spreader. in this The from its of thematerial hopper is effected by a rotating roller, which isdriven by the wheels of the spreader. The rate of material by controlled spreadis flap whih presses against the rubber material-dispensingroller. his dump the truck driver raises In operation, body 1.5 ydto dischargeapproximately or sand into the spreader of salt hopper Theroller drive and salt is is then engaged to the wheel dispensed inproportion of the spreader to the rotation wheel. No operating controlsare needed in the drivera cab. The driver need only stop the occasionallyto refill his dump body. An advantage hopper by raising of spreader is that the salt of thistype is laid down directly under the spreaderand it is not thrown to either side. It is good for applying salt toramps, interchanges, areas, and other places where the not be spread around very much. It is also very effective materialshould inapplying salt to an area such as a passing lane which needs after the traffic dry. Someorganiations treatmentlong lane has become find thistype of spreader the early useful for combating fall storms or the small, and when the larger storms, which are usually latespring spreaders It arenot chassis. when mounted on truck is also useful periods during heayduty spreaders inoperative.81 thlarge are

The principal

are that they advantages of this type of spreader to buy and maintain when compared to a chassis-mounted areinexpensive spreader(they controlledspreader); that of a slip-in cost about one-third they particularly make good use o existing dump trucks, the2-3 ton size; and they can a few minutes.The for service in just be ready disadvantages are that not spread while backing up, theycannot spread they do useful for expressway) material on more than one lane at a time (not the truck periodicallyto fill the spreader. and dumpbody must raise he (This that the truck highway and stop. operation offof the requires pull Filling on the theraised run is dangerous because dump body may atch Modiications overhead and bridges).Spreader for branches, wires MaterialsHydraulic spreaders utilize Different

a hydraulic which drives unit, motor attached to a 50:1 gearreduction the slow speeds at which the hain belt. The heavy starting loadsand spreading of chemicalsat place low rates an extreme the motor runs during of Public load motor. Works on this The MassachusettsDepartment uses gear box motor and the 50:1 a three-speed between thehydraulic has 3:1 gear reduction unit, which drives the chain-belt. Th gear box a is used reduction, and a directdrive. The 3:1 reduction 2:1 reduction, spreading, the 2:1 reductionis spreading during salt a mixture used for and the spreading sand. of sand and salt directdrive is used for (50) torque With the 3:1 reduction, runs at an efficient the hydraulicmotor the chain allows the and speed, and belt is pulledat peed that spreader a material at a rate as lowas 75 Ib per lane mile when the to deliver opening is 1 in.The hydraulic these system used to drive spreaders the truck. Co also used for cotrollingplows that may be atached The preferred pump-drive systemis on attached through to a coupling the rankshaft pulley at the frontend of the engine. The engagement of the pump occurs by coupling means of amechanical which must be made up when the engne is stopped, orby means that of a mechanical lutch can be shifted manually Some hydraulic systems are driven or by airpressure. from power take-offlocated oil the truck The hydraulic on the transmission. reservoir should be ofsufficient that cooled to can be size the oil steady-state operatingtemperature during the wort operating conditions. is these Often, reservoirare mounted on sprader units, particularly older the chassis unit, and directly behind the cab.Some

most of those with sallapacity, are powered independently by a small air-cooled engine,whih gasoline is coupled Remote through a centrifugal clutch. on-off the major controls andthrottle setting are these means of regulating spreaders.GROUND-SPEED CONTROLLERSArecent addition to the control system for hydraulic

hemical spreadersis a control unit, the spreader feed which synchronizes mechanism with theforward control This automatic type motion of the truk. relieves thedriver of the burden application of the of manual control rate of alt83


and/or sand attention


other chemicals a storm; during and other on driving, plowing,


he is




responsibilities.Ground-speed controllers for controllingthe are a most importat piece of equipment More importantly, they enable rate application. of chemical spreadingof hemicals only when the truk is in motion and go a long way towardeliminating chemicals that spreading of inevitably occurswhen the wateful one reason or another, a vehicle is topped, for and the spreadercontinues are capableof groundspeed to operate. Further, controllers these spreading to the speed at which the truk chemicals in proportion istraveling. At slow amount of chemical speeds, is spread, whereas,at high a small speeds, are released. effet quantities The net is thata larger uniform quantity goesThe basic is spread on each mile the truck requirethat the of all ground-speed controllers principles forward (or backward) motion of the vehicle most be measured.In end control of theback systems, the rate forward motion is monitored at of the transmission cable by the speedometer pickup sensesrotation which of the drive shaft. Other points at which truck motion are can besensed rides in the front wheel or wheel that top of oneof the rear an idler on wheels and drive rotary is motion sensor. The purpose of thesensor a to provide its rotary a signal proportional motion. to Onecommonly-used inludes past sensor permanent magnet that, an eight-pole as itrotates signal* a fixed coil, produces sensoruses Another the desired photoelectri cell located directly opposite Between a tungsten filamentlamp. is a card two units to the rotating element of thesesor these and attahed As multiple, evenly spaced with perforations around itsperimeter. it passes this between cell and the incandescentlight, the photoelectric card the light, are in for liht that interrupts of thus providing the pulses proportion to the rotational types are two basic of speed of the sensor.There controllers: SystemThis type of controller utilizes the openloop andthe closed-loop.Open-Loop Control ground-speed operating of rate

a usually attached at thespeedometer point able on the single sensor Pulse signals transmission. fromthis to the control sensor are fed circuit 26where the signal shown schematially i igure is amplified, ompared with to signal and witha control signal, which is a calibration in proportion salt.This is then used to control a motor the desired amount of signal that opens or closes the hydraulicvalve controlling of chemical flow rate from the spreader.A open-loop controller is shown in typical 27. This unit sit on top of a standard hydraulic Figure is desigedto spreader. valve for ahydraulic feature this control of A desirable is can control manually of the unit that theoperator the operation in in system.85 the eventof failure of the control any part ontrol spreader




it s simple The advantage cotrol system is that of the open-loop andrequire the open-loop disadvantages of system arethat only one sensor. The oilor of the hydralic changes in tmperature it annot compensate for other the sensitivitiesof sytem, and temperature degradations in the hydraulic electronics may provide inaccuracies control circuit in in the thecalibration.Closed-Loop Control control SystemA closed-loop two sensors, the attachedto system utilizes one usually transmission the output attachedto point and the other of the speedometer shaft operates unit. of the feed mechanism of the spreader The controlsystem the 28. from shown schematically Thesignal in Figure on the principle is compared with inputsignal sensor (which truck-speed the control is signal amount of salt) proportional and to afeedback to the desired the from the output The signalfrom shaft of the feed echanism. forward-motion system thatspreading can sensor of the truck tells the control tells theontroller how tocommence. setting controller on the The control whichthe truck is moving. set the hydraulic valve opening for the peed at output feedsback The sensor on the shaft of the spreader a signal which the to the spreading indicates controller whether or not the spreaderis controller,a feed mechanism desired type of amount of material. With this control under all in the drivingconditions acuracy of 2 can be achieved vehicle speed range from approximately 0.2 to 45 Figure 29 shows a ground-speed ontroller that utilizes mechanism and vehiclespeed unit a photoelectricfeed sensors and that has a manual overridecapability for controlling in the event of a failure.Some ground-speed circuit the hydraulic controller are equipped with a control featurethat allows an additional of salt areassuch to be spread on ritical as at intersections, of hills. usually bridges, or on steep portions switch This"blast" approximately 20% materialfor application one-time to critical DISPENSING SYSTEMSMany jurisdictions units have been experimenting

amount on provides areas.LIQUID

with recently of saltwith various materials to speed in order up its action, particularly attemperatures near limits at which salt the lower is useful and to keepthe material it i from bouncing off the road when spread This IV.A techniqueis discussed typical truck-mounted in Chapter calcium-chloride dispensing system fitted shown schmatcallyin Figure 30 has a stainless steel or fiberglass tank intothe area between the truck and hopper. The the spreader positive-displacement pumpshown is sometimes with an electrically replaced driven,magnetically all-plastc control coupled, valve. pump and a solenoid Aspray bar (sometimes fitted with fan nozzles) dispenses liquid calciumchloride into chute of the spreader.87 the discharge


orother A disadvantage chloride solution of salt with calium solutions that equipment, operatingprocedures, is it requires additional speial of tank for 4,000-8,000 gallons each and storage liquid materialat maintenane the end of depot. Each system must be flushedat truck-mounted calcium chloride acceleratesthe Also, the addition of corrosion a storm. of equipment water moisture theair.SNOW from attracts because it PLOWSAfter snow has cease comes time when chemical operationsmust accumulate there and snow has must begin. occurs when about 0.5 in.of This usually accumulated of plows areavailable and more is for predicted. A multitude snow and ice control shouldbe chosen to work, and the particular design thenature match the type of expected in snow condition the area, of the system (high-speed or downtown, and road arterial, or residentialareas), the that the following the plow. Summariedin will be used to propel truck paragraphs types of plowspresently in of the major are description use. PlowThe begun to plowing high-speed plow shown

on one 31 is characterized conical-shaped which is small in Figure by end and large on on the other typeof plow is typically used end. This very large plows the snow in only one vehicles (weighing tons or more)and usually the road although some high-speed plowsdirection, to the sideof are in service. from the large is contoured the snow leaves The so that end on theblade out to the ide In light snow, blowing and is directed thisfeature of the improves the visibility driver so that he can ahieve ahigher plowing speed. The ontoured maximum lateralcasting provides distance, power is also required to push the plowTwo-Way and minimum PlowA popular for all-around use is the two-way, power reversible, plow straight-edged plow with a constant cross section shown in Figure 32. Thispopular plow made in sizes feet n ranging from up to 14 feet widthand is used is in ranging vehiles in size from utility vehicles up to thelargest four-wheel drive plow trucks made. The power-angling characteristicsare useful for either to the right plowing or to the left and, upon on multiple-laneroads occasion, snow directly are used for pushing ahead of thetruck (e.g., for clearing limits of parking areas). The constant cross section ofthe the speed at which this snow, because the inlight type of plow can be used snow has a tendency over the front ofthe to come up at high speed thus reducing between the the visibility of the driver. PlowA compromise high-speed and the two-way This plow plow is the two-wayhigh-speed plow. has a straight cutting edge is capable of casting upon the orientation snow either of the plow.91 to the right

which and a double-formed or to depending theleft

PlowIn 33is drifting plow shown areas where moderate a in Figure may ocur, useful Typically large the drift. plow is mountedon for bucking through a plows truck, with dualwing drive and is used in ombination four-wheel to open areas subject to minor drifting.Wing PlowThe keep wing plow

(igure is a veratile whih canbe used for 33) piece of equipment, pushing back high drifts or the earlier acumulated snow left overfrom storms along the edge often for of the road. alsoused In tandem it is plowing In thisoperation light highway. the snow on a multi-lane snow two-way plowis caught by the collected by the truks front-mounted wing pushed back further thus increasing plow and of road cleared thewidth in single pass by one one or two wing truck. equippedwith In trucks plows, second operator required to operatethe wing plow is particularly accumulated snow in thevicinity road signs, when of culverts, and guard rails. equipped ScrapersTrucks wth are useful scrapers

for removal snow from roadways 33) These plows are (Figure of hardpack exertingdwnward the apable of pressure cutting edge of the plw and on breaking thrughice and hard pack under some circumstances plows are alsouseful for removing light (up accumulations snow of to 2 in Theremote of the angle control feature of the plow is desirable.Additional Features of PlowsAll snow plows must be able to be lifted from the of the roadwayby the surface

operator remote control through usually accomplished by a hydrauliccontrol system operated from the cab. In addition have plows should amechanism, whereby the trips or the whole plow itself when itmeets an immovable object, manhole cover, frozen rock post,thereby such as a or a minimizing the shock transmitted and driver that might and thedaage to the truck be incurred by the plow itself.All front-mounted plows must have hitch firmly attached to the frame and to ofthe truck which the plow itself can be attached rapidly variety whenneeded. wide of hitches are available, arefabricated or modfied in many of whih the maintenance shops of the various municipalitiesMany organizations find that cutting plow edges that eliminate have tungsten carbideinserts the cutting need for changing give far longerservice, edges, and are well worth the additional purchase cost.or where the minmum temperature areas rubber cutting edgesfor is 28-32°F, have been used with some sucess for removing freshly trafficmarkers.8,9 with raised or other chemicals93 fallenor Even slushy in this snows from temperature roads range, equipped salt

nowwhch ca be to keep the snow from packig and to produce must be ued cutting plowed. are notuseful when the easily edges Rubber or temperatures temperature range of28-32°F and steel the critical are below or carbide-insert some blades are needed to rmove the snow.GRADERSIn muniipalities, road shoulders are used that are used during the summer forrading graders or the winter time for snow-plowing two axles, singleoperations.With in four-wheel axles these graders can be with two reardrive, drive, or three is plow. Such a unit equipped with a heavyduty twoway front-mounted lots for clearing useful straight-line operationsand parking for both is often the other blade and large The easily controlledscraper areas. only ice of equipment pak that is capable hard and piece ofremoving from roadway surfaces.FRONT-END LOADERSThe rubber-tired, front-end loader materials for ice control is the equipment of hoice handlingsnow and such in the (hinged as sand, salt, and mixtures thereof.The articulated middle) version machne providesmaximum size. for a given of this machine. of construction Such machines canbe used year-round for a variety operation versatility tasks.Considerable in a plowing and maintenance Is provided when a largefront-end for plowing is equipped as shown loader 34. tight in Figure Thisunit capable of maneuvering in very is qarters, an extremely and the articulatedmodel can make a sharp, turn, useful feature forurban is provided with front-end loader a snow plowing.When two or more different

bucket sizes,savings are ahieved. of time and wear on equipment small-volume bucketwill during the summer prevent overloading of the machine season, will and alarger increase productivity when salt, bucket sand and snow arebeing season. plowing handled the winter during For a operation, amachine at 2-2.5 yd is preferred. rated For general loading rated at 1.5 yd- and equipped operations,a machine with a 2-yd3 bucket is preferred.SNOW many instances, snow blowers BLOWERSn are the only means whereby roads bemaintained open. These onditions occur in the high mountain passeswhere occur, in areas heavy where heavy driftig is frequentand areas in where rapid suchas on removal of acumulated snow is required airport runways. large applications, For these heavy-duty snow-blowing machines similar 35 have been the ones shown in Figure to developed.Equipped with two large is capable engines, unit of castingas this much as tons of snow per hour a distance up to 125 feet.For lighter-duty 3,000 units operations, are utilized.Smaller capacity units of smaller can are used for road (such as downtown clearing areas) whenclearing and for loading truck cannot be stored.95 in which snow areas

A popular in light-duty is the selfpoweredunit new oncept snow blowers that loader is attached to the lift forks as shownin of a front-end located Figure 36. shown has its power unit he unit Immediatelybehind the augers and blower. models, Other powered by hydrostatic units,have mounted on the back end of the loader and rely a power unit uponheavy-duty motors for powering and blowers. hydraulic the augers Aparticular is that can cutdown advantage loader it unit of the front-end high drifts uniton (snow depths up to 12 feet) by raising the blower the loader at successively lower arms and cutting the drift into levelsFront-end tons perhour mounted units are made with capacities of up to 1,500 and can cast the snow as far as 100 ft.97

CHAPTER VISPREADER CALIBRATIONCalibration action of all chemical is the most important preaders thatan the amount of harmful agency can take to control and reduce chemicals that enter the environment. of spreaders not onlycontrols Calibration and redues saves oneyby providing he amount of material used but it also of a objectives level of service with less chemicalsThe the desired thorough calibration of the program are very accurateknowledge amount of chemical and units spreadersetting delivered by all at each identification controlled and repair of all than cannotbe spreader units within he range of prescribed spreading.Spreaders should be annually calibration calibrated before the winter season begins.The the hydraulic be during the winter the majorparts if any of of are are replaced, if the of the spreader moving mechanicalparts rate becomes or replaced, or if for any reason thespreading should be calibrated should system damaged suspect.Spreaders

the truck travels not only for amount of salt dispensedeach mile the but also for the pattern of distribution ofmaerial on he road surface.n section two basic this ways of are calibrating forthe chemical spreaders amount per mile traveled of the described. measurement One method, involves a yard calibra¬ion, setings of delivers over the com¬plete range of control amount the unit an in-service The second, is a calculation the spreader. calibration, based on actual operaioni.e., delivered over a total spreader load stretch of road of known length.YARD Wihout CALIBRATIONSreaders ControllersThe calibration technique described in based



is primarily Institute onmethods developed under their by the Salt by the Michigan Sensible Salting Pro¬gram, with modifications incorporated to Deparment This technique of StateHighways and others. is applicable rotation hopper-type spreadersand spreaders, both of which rely upon the of forfeeding amechanical (an auger shaft or shaft) element sprocke chemicals and/or abrasive materials from the vehicle to the dis¬tribution controlled mechanism of the spreader. to Although applicable spreaders, the technique adaptable is also to independentlypowered units.Equipment spreaders RequiredThe required equipmet for calibration of salt includes:98


A scale

The scale he can be weighing amount of salt. ahand-held of or platform type and should be capable weighingquantities resolution between Ib and 100 Ibs, with of2.0 Ib. The accuray of the scale eitherby be verified should the agency department of weights and measures or withseveral calibration weights.• A for collecting of chemical material(a up to about 100 Ib square yard of at each comer canvas with or aburlap sack). 0.5Ib, the tare For any collector weighing more than about weight should be determined.• A stop watch for or a watch A shaft (if with second hand for timing shaftrevolutions.•


tachometer rotation shaft means for






by counting)•

placing will those

mark on the dob of pen, a do• Calibration shown in Figure

end of th auger pant, a filemark worksheets like 37.J• A clipboard


sprocket or a prick

shaft. punch

A marking mark

or data

other are

means being assembled.Calibration

for holding

calibration worksheetswhile ProcedureThe following is thatdo


recommended spreaders calibration of for end of Clean the shaft the



ground-speed controllers.1.

auger or sprocketshaft. mark on Place an index the end of per the shaft revolutions sothat the number of minute end can be countedat If the shaft each dial setting. is not exposed,mark auger sprocket.2. Remove the the spinner disc or bypass the spinner system motor with ahydraulic With line.3. the spreader running and empty, let a salt to the truckidle normalworking in the truck loadon put actualworking is running long enough temperature.4. body the spreader. conditions5. at to hydraulic warm the Place load a half oil of to

This partia load Open he throttle

wll simulate so the engine

approxmatelyworking the durngsalting.100

speed. If the truck is at the engine throttle

with a equipped tachometer,set normally used speed


hopper-type open the gate to the spreaders, appropriatesetting for which the spreaderis for the type of material being calibrated of salt (salt, and calcium chlorde,salt/sand, sand, abrasive). and error adjust¬ments Trial or other may toge the have to be made in the gate opening in order spread desired Fill rate.7. spreader auger Set the motor or onveyor with salt by rotating ita few










When the

auger is plae the canvas or the bag underthe full, discharge openng so salt dischargedis caught. of the that all to make oneful turn at Allow the auger or the sprocket a low settng that Isdscharged.10. and collect salt the Weigh the deducting salt the weight of the canvas quare,bag or other collector. Accuracy Is important factor becausethis Is used Forgreater repeatedly accuracy, in the calculations. take the andthen repeat step 9 above several times average worksheet weight and enter in Column 3 ofthe (Figure per revolutionhas 37) One the weight been establshed that the weight wll reman constantthroughout calculating To determine the procedure.11. number of revolutions or a watch wth per minute use a stopwatch a second hand; count thenumber of of the auger or sprocket each control If necessary, use hand haftat setting. In Coumn 2 of tahometer.Record these the worksheet in Figure of 37.CalculationsThe worksheet two piece now contans


needed 1 mill. rate in number of in

that will for calculation amount of salt be discharged ofthe Column 2by Column and enter the result Multiply (discharge 4.To complete the calculation, in Colun you need to know the

minutesrequired road travel one mile at various for the truck to speeds. Theseare tabulated In Table 7 and shown in Column 5-10 of the worksheet truck is traveling Tocalulate the amount spread per mile when the at 15 multiply shown at the head of Column 5 Column 4 by the constant in the proper to determine Likewise, the plae. andenter the result 25, 30, 35 and 40 multply by the constants amountspread at 20, Column atthe and enter top of Columns 5-10, respetively, the results in the properspaces. an these Perform control setting.As calculations for every illustration how the table is used, assume, for example, thatthe of auger or sprocket disharges Ib of salt (Colmn 3) each101

time it makes one full revolution at control settng number and thathe 10 tmes per minute (Column 2) Obvously, spreaderwill auger turned the Column 3and put setting minute at that (Column 2 times out 80 Ib per the a result entered Column 4)At in speed as shown in Table 7 the truck every4 min. 15 moves one mle Therefore, 80 multiplied Thisvalue is entered by 4 min equls 320 in Column setting for 5 for control number 3. This procedureshould be repeated each control setting various atwhich the material is and at the speeds spread. next set of data on worksheet Record all (Figure 37).The calculations of for will travel determines the distance the spreadertruck that load is various complete settings speeds beforethe control and vehicle exhausted. and calibration for These values are useful checkingthe overall worksheet, health of spreader. Column 11 of thecalibration the In sand or enter the size of the for thematerial (salt, load in pounds material when it mixtures the This should be the weightof thereof). of the spreader is loaded with the op of the screens level orthe top gross weight). hopper (provided this does not exceed the vehicle'slegal This or by either from the spreadermanufacturer value can be obtained weighing a truck theamount in the line full of material and entering provided for empty the spreader in Column 11. the -time requiredto To calculte the settings control divide Column 11 byColumn 4, and enter various results the willtravel before that a truk at 15 in Column 12. The miles load constant by divisionof is exhausted is determined Column 12 by the the top of Column 13. Likewise,the will travel given a truck at miles in Columns 14 before loads are exhausted at 20-40 are calculated its through should be 18, respectively, on the calibrationworksheet. Results entered table to the nearest 7 VEHICLE SPEED CONVERSION in this 0.1 mi.Table FORSPREADER CALIBRATIONVehicle speed1015202530354045505560Time to travelone

(min) mile Calibration

CardThe last step In the alibration of the calculation onto calibration card,

spreaders of the resultsof is transfer which will be carried in the102

cab of the truck. the data from Columns1 This is simply done by copying and 5-8 onto the card shown in Figure 38,The side of the truck calibration check data in Colmns 13-18 should ontothe aide (the be transferred reverse) of the sam calibrationchart 39.On shown in Figure the truck calibration cards, color coding is very useful. For example,those calibration valus close to the most usually prescribed amount ofsal could be indicated in green, those higher than the prescribed than the onesin red, and those rates lower prescribed rate in black. At aquick can tell glance, the operator when he is in the properrange.The additional operating information called for on the truck calibration in. The calibration card shouldalso be filled of the is now omplete, spreader andthe worksheet calibration should be placed on file either truck or in the agecys for the in the mainten¬ance record be a office. The truck placed in calibra¬tion convenient ard should location for quick in the truck reference available during a so thatit is storm.In some agnies template is made from a block of wood whih has gate opening equal to the required onedimension for straight salt and anotherdimension to the opening required for another equal materal attached to the is often spreader such as sand.This templte calibration card.Spreader ControllersSpreaders with With Ground-Speed controllers are calibrated in the required previous in this paragraphs calbration but ith s the same


by the outlined same basictechique several noableadditionshe equipment ued for

thespreader ground-speed controllers except for a modified without worksheet.In be utilized for simulation pulse generator addition, must a of thetrucks sensor. can be one provided by the ground-speed manufacturera capable pulse generator low-frequency audio per of 100 cycles second by orwhos specfication be provided the controller manufaturer, can or ahomemade pulse with a standard truck generator sensor driven by a variable-speed These pulse generators with a tachometer. motor and equipped arebased on the fact that all speedometers rotate RPM when at 1,000 thevehicle is moving at 60 Special precautions must be taken if thetruck is equipped axle and does not have rear-end with two-speed acompensated be taken If this is so, care must speedometer drive. toinsure in the rear-end the speed etting forwhich that truck is used only speedometer correctly.Measurement the ProceduresThe is calibrated followng procedures are followed for calibration of with spreadersequipped ground-speed controllers.103

SpraderCaibrationPunds MateralGate

OpenngSpreader Truck NoLoad

Calbration Spreader pr


Disconnect pulse

the lead generator. of 30 2.

and connectthe speed sensor from the truck for a Set the pulse generator speedsetting

Clean an index shaft.Place the shaft end of sprocket the auger or revolutions mark so that the numberof on the end of the shaft it makes per minute eachcontrol can be counted at setting. If the sprocket the auger shaft end is not exposed,mark sprocket.3. Remove the spinner disc or bypass the spreader system the spinner motor with ahydraulic line4. With

enough to warm the running and empty let the truck idlelong Place hydraulic oil normal workingtemperature.5. to a load half of salt in the truck This the spreader. body to put a loadon partial condtions.6. load will actualworking simulate For hopper-type spreaders, for the type of open the gate to the appropriatesetting (salt, material for which the spreader isbeing calibrated other of salt and calcium sand or chloride,salt/sand, abrasive). Trial and error adjustments may have to be made in the gate in order to get thedesired spread rate.7. Open the throttle so that truck the the the engine working speed. atapproximately is running If ruck is equipped set tachometer witha the throttle engine Set the when speed normallyused salting.8. controller at its

at groun-speed

the spreader auger or lowest setting andactivate conveyer few to fill it byallowing it to rotate turns.9. Set the spinner motor control usual level.10. When the auger is full, place

to the


canvas the salt

of all or bag under thedischarge so that opening Allow the auger or the discharge iscaught. to make one fullturn the low setting of sprocket at this ground-speed is that controllerand collect the salt all discharged.11. deducting Weigh the salt, the collector. of the canvassquare, bag or other Accuray is importantbecause used this factor is repeatedly step repeat in the calculations.For accuracy, greater weight 10 above several tmesand then take the average and enter (Figure it in Column 3of 40) Once the worksheet the weight per106 weight


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