Long-Term Pavement Performance Program Manual for Falling Weight Deflectometer Measurements

Chapter 9. Equipment Checks

Because of the extensive use of FWDs in LTPP, routine equipment checks are extremely important. The FWD operator should perform the checks in this section each day that the FWD is traveling or in operation. These checks are a minimum. Operators are expected to keep an eye out for other anomalous conditions while performing these checks. These checks are not to supersede the manufacturer’s minimum requirements for warranty compliance.

An operator must address any deficiencies noted while performing these checks before any further transit or testing.

9.1 BEFORE-TRANSIT CHECKS

The operator should perform the following checks on the tow vehicle before the start of travel for the day:

• Fluid levels:

  -		Engine oil.
  -		Brake fluid.
  -		Power steering.
  -		Wiper fluid.
  -		Coolant.
  -		Transmission fluid.

• Battery connections.
• Hose conditions.
• Tires inflated properly and in good condition.
• Lights operational:

  -		Headlights.
  -		Taillights.
  -		Turn signals.
  -		Brake lights.
  -		Strobe lights.

• Interior uncluttered, equipment stowed well.

The operator should perform the following checks on the FWD trailer before the start of travel for the day:

• Ball tight.
• Safety chains in place.
• Breakaway cable connected.
• Break fluid level good (for trailers with hydraulic brakes).
• Trailer battery connections good.
• Lights operational:

  -		Taillights.
  -		Turn signals.
  -		Brake lights.

• Tires inflated properly and in good condition.
• Transport locks engaged.
• Hitch pin in front sensor bar guide.
• Covers and latches secure.

9.2 BEFORE-OPERATIONS CHECKS

At a minimum, the FWD operator should perform the following checks after the FWD arrives at the test site and before testing begins:

• Trays removed.
• Transport locks unlocked.
• Hitch pin removed from front sensor bar guide.
• Hydraulic oil level good.
• Raise/lower bar cable not frayed and well adjusted.
• Geophones well-seated in geophone holders.
• Geophone holder springs and foam guides in good condition.
• Ribbed rubber sheet on load plate in good condition.
• Load plate swivel free-moving.
• Pressure switch boots in good condition.
• Trailer control box electrical connections tight.
• Buffers have no cracks or slits, and are level and tight.

In addition, the operator should observe and listen to the hydraulics during the buffer warm-up sequence to ensure that they are free of air and operating correctly.

9.3 POST-OPERATIONS CHECKS

At a minimum, the FWD operator should perform the following checks before leaving the test site:

• Transport locks engaged.
• Hitch pin replaced in front sensor bar guide.
• Pan replaced and secure.
• Trailer access doors locked.
• All supplemental testing equipment properly stowed.
• Paper forms filed out, dated, signed, and filed.

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