Maintaining Deflection TestingMaintaining Deflection Testing Equipmentq p

Dave MorrowDave Morrow

Dynatest Consulting, Inc.

Types of deflection testing equipmentequipment

Light Weight Deflectometer (LWD)

Load up to 3,300 lbf (15kN) p ( )

Unbound materials (base, subgrade, …)

Falling Weight Deflectometer (FWD)

FWD: 1,500 – 27,000 lbf (7 – 120 kN)

FWD TMD

Heavy Weight Deflectometer (HWD)

HWD: 6,500 – 54,000 lbf (30 – 240 kN)

Other Dynatest productsOther Dynatest products

Friction testingFriction testing995 Tire Traction Tester

6875 Runway Friction Tester

1295 Locked Wheel Tester

Pavement ProfilingPavement Profiling

5051 Mk IV Portable RSP

5051 Mk III RSP

Heavy Vehicle SimulatorHeavy Vehicle Simulator

HVS Mk IV

HVS Mk VI

Typical FWD Testing

FWD/HWD Plate Diameter: try to match stress level (tire pressure)

Small Plate (300 mm ø ≈ 12”): Highways

Large Plate (450 mm ø ≈ 18”): Airports and Unbound layers

Number of drops per test location

One unrecorded seating drop [lowest load level: drop height 1]

Two/three recorded drops [various load levels or one load level]

Rigid PavementPortland Cement Concrete (PCC)Portland Cement Concrete (PCC)

Load Transfer Efficiency

`Curling/Warping Effects

FWD Star Bar

Load Transfer Efficiency at Longitudinal, Transverse Joints or Corners

S

Pressure Distribution + FWD Testingg

Properly maintained deflectionProperly maintained deflection equipment will:

• Spend less time on jobsite– Limited runway access

– Less exposure to trafficLess exposure to traffic

– Cheaper travel expenses

A id ibl d t i• Avoid a possible second trip

Properly maintained deflection equipment will:

• Have less down time– An F/HWD can earn $1,500 - $2,500 per day$ , $ , p y

– A breakdown on a closed runway will not earn points with OPSpoints with OPS

Properly maintained deflection equipment will:

• Yield better results; All analysis performed is based on data gathered g

Properly maintained deflection equipment will:

• Provide better data for your Pavement Management Systemg y– Over/under estimation of bearing capacity can

have a significant effect on maintenance costshave a significant effect on maintenance costs as well as remaining life calculations

Equipment maintenance has three aspects: mechanical

i lib ti d trepair, calibration, and operator involvementinvolvement

Mechanical repairs insure that the equipment won’t break down

Routine calibration insures that the d h d i lid ddata gathered is valid and

useableuseable

Operator involvementOperator involvement

Thank youThank you