828.02 Vehicle Loop Detector and Loop Detector Wire
828.01 Description
This work consists of providing and installing a solid state digital inductive vehicle loop detector and loops.
828.02 Materials
Provide and install the following materials in accordance with the latest edition of NEMA TS -1 or TS -2.
A.Detector Loop Wire Provide detector loop wire embedded in the pavement in accordance with Subsection 738.01, “Traffic Signal Wire and Cable.”
B.Shelf Mounted Detector Unit Provide a self -contained, self -tuning, solid state digital detector that automatically compensates for temperature variations and environm ental conditions.
1.Mechanical Requirements Provide a detector unit and power supply enclosed in a sheet -metal housing with a protective paint finish. Ensure that the case allows access to the interior assembly and allows parts testing and servicing. S upply each detector unit with a connecting cable. Insert a multi -terminal plug into the plug receptacle on the face panel of the detector to make an electrical connection from the detector to the incoming and outgoing circuits. Ensure detector replacemen t without disconnecting and reconnecting the individual wires.
2.Output Delay and Extend Supply the loop detector unit with programmable delay and extend output features.
a.Delay Output Provide a delay circuit variable to at least 20 s in 1 s increment s for delayed output. Ensure vehicle detection delay for the time period selected to prevent detector output until vehicle presence in the loop for the selected length of time. Ensure the vehicle delay timing resets each time the vehicle vacates the loop . Ensure the delay circuit immediately disables in the presence of 120 V (AC) on Pin J of the MS 3106A -18 1P connector for this channel.
b.Extend Output Provide a variable extend circuit for carryover output to at least 15 s in 0.25 s increments. Ensur e detector actuation extends after the vehicle leaves the loop. Ensure the timing circuit resets the after the extension expires. Do not disable the extend circuit in the presence of 120 V (AC) at Pin J of the connector. VEHICLE LOOP DETECTOR AND LOOP DETECTOR WIRE 828.02 Provide digital timing. Ensure u se of pins, thumbwheels, or dip switches for programming settings. The Resident Engineer will not require delay and extend features to function simultaneously, unless otherwise shown on the Plans. Provide external programming capability on the face of the unit.
3.Operating Requirements Design the detector so environmental metal objects near the loop do not affect operation. Ensure the lead -in cable is located in a common conduit with signal and interconnect cables without interfering with detector opera tion. Ensure the detector operates in temperatures from −30 °F to 160 °F [−34 °C to 71 °C] with an online voltage of single phase 120 V (AC) 60 cycle. Accommodate online voltage variation of 15 percent without affecting the operation or life of detector e quipment. Provide the detector unit with a tuning range of loop inductance from 40 µH to 700 µH. Ensure the detector detects vehicles traveling up to 100 mph [160 km/h]. Ensure the detector detects vehicles that pass over any part of the loop. Ensure th e detector returns to its original condition after a power failure.
4.Electrical Requirements Provide solid state detector circuitry. Provide a printed circuit board in accordance with Section 825, “Traffic Signal Controller Assembly.” Provide facilities on the front panel for adjusting the detector. Provide for a simplified loop tuning procedure without a test apparatus or traffic. Provide a detector unit with switches on the front to independently select the pulse or pres ence operating mode. Provide each detector channel with a surge protector (EDCO SRA -16C-1, or an equivalent approved by the Department's Traffic Engineering Division). Provide the detector with a multi -conductor color coded harness and MS connector. On the front panel, install a fuse (replaceable without tools) for each detector unit. Permanently ground each detector unit internally. Provide an indicator light on the front panel to show vehicle detection.
C.Card Rack Detector Unit Provide two channel, self-tuning, solid state, digital card rack detector units that automatically compensate for temperature variations and environmental conditions in accordance with NEMA TS-2 and Subsection 828.02.B, “Shelf Mounted De tector Unit.”
D.Card Rack Assembly Provide a card rack, cross -wired for two or four channel operations, that will accommodate at least eight detector units. Provide an aluminum detector card rack frame with modular slots allowing the PCB edge connectors t o plug into the rear while sliding between top and bottom card guides for each module. Provide mounting flanges turned outward. To allow the card rack to swing out, provide slack in the wiring and hinge on one side and fasten with thumb screw connectors on the other side.
828.02 Vehicle Loop Detector and Loop Detector Wire
E.Power Supply Provide a 24 V (DC) power supply that delivers at least 3.6 A. For a shelf -mounted power supply, ensure the front panel of the power supply provides power on LED, a power on -off switch, a fuse for the 120 V (AC) input li ne, and a connector. Provide a connector with a metallic shell internally connected to the chassis ground that is compatible with an MS -3106A -18-1SW cable connector. Provide connector PIN terminations in accordance with Table 828:1: Table 828:1 Connector PIN Terminations PIN Function A AC Neutral B Reserved C 120 V (AC) Line D Reserved E 24 V (DC) Output F Reserved G Logic Ground H Chassis Ground I Reserved J Reserved
F.Vehicle Loop Wire Sealant Provide and install loop wire sealant for installing vehicle detector loops in asphalt and concrete pavement as shown on the Plans.
1.General Requirements Provide a one -part polyurethane sealant for asphalt and concrete pavement. Ensure that the sealant allows traffic to travel over the filled slot immediately after application without tracking. Provide sealant that will not shrink in volume.
2.Physical Properties Provide sealant with a shelf life of at least 12 months. Provide sealant with uncured and cured properties specified in Table 828:2 , Table 828:3 , and Table 828:4:
a.Uncured (Wet) Sealant Provide uncured (wet) sealant with the following properties: Table 828:2 Physical Properties of Uncured Sealant Property Requirement Test Standard Weight 717.87 lb/cycle ± 1 lb ASTM E 201 VEHICLE LOOP DETECTOR AND LOOP DETECTOR WIRE 828.02 Table 828:2 Physical Properties of Uncured Sealant Property Requirement Test [1,210 kg/m3 ± 0.45 kg] Total Solids by Weight, 18 hr at 200 °F [94 °C] 75% – 86% by weight ASTM D 1353 Viscosity, no. 6 Spindle at 20 rpm, 77 °F [25 °C], 50% relative humidity 0.00073 psi•s – 0.0123 psi•s Brookfield RVF [5 Pa•s – 85 Pa•s] Curing Time, 50% relative humidity Touch: ≤24 hr ASTM D 1640 / D 1640M 4 mil [1,000 µm] film, 77 °F [25 °C] Complete ≤36 hr —
b.Cured Sealant Provide cured sealant with the properties specified in Table 828:3: Table 828:3 Physical Properties of Cured Sealant Property Requirement Test Hardness (Indentation) 65 – 85 ASTM D2240 Model 1700, 25C, 50% relative humidity Tensile Strength, Die C Pulled at 20 IPM ≥125 psi [862 kPa] ASTM D412 Elongation, Die C Pulled at 20 IPM ≥200% ASTM D412 Adhesion, Canvas to Concrete 15 lb/in [0.3 kg/mm] wide ASTM D903 Application Temperature 41 °F – 131 °F — [5 °C – 55° C] Service Temperature −40 °F – 150 °F — [−40 °C – 65 °C]
828.04 Vehi Cle Loop Detector and Loop Detector Wire
c.Resistance Provide cured sealant with the chemical resistances specified in Table 828:4: Table 828:4 Chemical Resistance of Cured Sealant Property Result Test Deicing No effect ASTM D 471 Gasoline Slight Swell ASTM D 471 Hydraulic Brake Fluid No Effect ASTM D 471 Motor Oil No Effect ASTM D 471 Sodium Chloride 5% No Effect ASTM D 471 Conduct the ASTM tests from 70 °F to 77 °F [21 °C to 25 °C] for 22 hr
3.Application of Sealant Apply the sealant as shown on the Plans. The Department may test to ensure compliance. If a sample fails, remove and replace with new sealant as approved by the Resident Engineer.
828.03 Equipment — Vacant
828.04 Construction Methods
Locate the loop detection system as shown on the Plans. Mark and maintain the detection system locations on the roadway for approval of the Resident Engineer. Cut the induction loop slot and corner cuts to the dimensions shown on the Plans. Use compressed air to clean and dry the slot. Wind loop wires in the same direc tion. Provide loop wire in a continuous length to the pull box, and connect to the lead -in cable. Use a blunt wood instrument to place the wire into the slot without damaging the insulation. Make all connections between loop wire and lead -in cable in the pull box. Solder the connection with a 60/40 alloy, rosin core solder. Avoid damaging the wire and cable insulation while soldering. Place a water -tight connector sealing packet over each completed connection. If no lead -in cable is necessary, directly connect the loop wire to the terminal block in the base of the traffic signal pole. After placing the loop wire and backer rod in the slot, check the circuitry, and seal the slot with a sealer required by the Contract. PEDESTRIAN PUSH BUTTON 830.05
828.05 Method of Measuremen T — Vacan T
828.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit:
A.VEHICLE LOOP DETECTOR Each
B.LOOP DETECTOR WIRE Each or Linear Foot [Meter] SECTION 830 PEDESTRIAN PUSH BUTTON
830.01 Description
This work consists of providing and installing pedestrian push buttons and signs on traffic signal installations.
830.02 Materials
Provide phenolic -enclosed precision snap -acting single -pole, single -throw pedestrian push button switches with screw terminals rated at 5 A at 125 V alternating current in accordance with Americans with Disabilities Act (ADA) Section 14.2.5. Provide materials for pedestrian information sign s as shown on the Plans.
830.03 Equipment — Vacant
830.04 Construction Methods
Install the pedestrian push button in accordance with ADA requirements. Design pedestrian push buttons to prevent tampering and electrical shock. Attach the pedestrian push button and sign to a traffic signal pole or steel pipe as shown on the Plans. Shape the housing to fit the curvature of the pole or pipe. Secure the housing to provide a rigid installation.
830.05 Method of Measuremen T — Vacant
Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 856–860 of 935.