3/26/08 Field Testing and Modelling of the Italian Smart Runway Instrumentations Silvia Portas Imad L. Al-Qadi Mauro Coni Hao Wang Jongeun Baek Italian civil aviation authority Ente Nazionale per l’aviazione civile SOGAER UNIVERSITA DEGLI STUDI DI CAGLIARI Dipartimento Ingegneria del Territorio

Outline Introduction Objective and Scope 3/26/08 Outline Introduction Objective and Scope Site Description and Instruments Responses from Instrumentation Preliminary Results from Modeling Summary

Introduction A reconstructed runway was instrumented to measure: 3/26/08 Introduction A reconstructed runway was instrumented to measure: Stresses Strains Temperature profile Moisture content Monitoring parameters affecting pavement behavior Airplane traffic intensity Loading maneuver Airplane speed Environmental conditions

3/26/08 Objective and Scope Analyze runway pavement response under various loading conditions: Pressure profile Strain response Predict runway pavement performance: Pavement response measurements Pavement structure modeling Better runway pavement response understanding

Instrumented Site Cagliari’s Airport main runway Location close to runway Head between Aiming Point and TDZ

Pavement Cross Section

Selected Instruments H-type strain gauges for HMA 15 Selected Instruments Strain and deformation measurements: H-type strain gauges for HMA Specially-modified LVDTs for unbound materials Pressure measurements Hydraulic pressure cells Environmental condition measurements: T-type thermocouples; TDRs Instruments were selected based on the type of response to be acquired, working range and material type. H-type strain gauges were selected to measure strain for HMA layers. Linear Variable Differential Transformers (LVDTs) for measuring displacement on three direction for unbound materials. Hydraulic pressure cells were selected to monitor the vertical pressure distribution through the entire runway pavement. T-thermocoples to monitor temperature profile and Time Domain Reflectometers to monitor volumetric moisture content were selected.

HMA Strain Measurements 15 HMA Strain Measurements 45 H-type strain gauges to measure strains at the bottom of HMA layers 9 Longitudinal 9 Transversal 18 H-type strain gauges were installed at the bottom of each HMA layer 9 to measure strains in the direction of the traffic and 9 perpendicular to the traffic direction. They were all connected to a high temperature resistant cable.

Deformation Measurements 36 LVDTs to measure deformation in granular layers Macro Sensors LVDTs GHSER 750-1000 Macro Sensors LVDTs GHSE 750-1000

Vertical Pressure Measurements Hydraulic pressure cells to measure vertical stresses under pavement layers 9 on each layer

Temperature and Moisture Measurements 15 Temperature and Moisture Measurements In-house built T-type thermocouples to measure temperature profile Time Domain Reflectometry to measure moisture content of granular layers Campbell Scientific 2-probe CS 616-L Calibration using in-situ materials

Instrument Response Instrument responses to two loading types were measured: Impulse loading: Falling Weight Deflectometer Moving load: truck at four various speeds

Pressure Cell Response 15 Pressure Cell Response

Data Collection Method Real traffic data Triggering system Collection frequency Collection duration Traffic Monitoring Airport traffic data Video camera

Current Traffic & Expected Measurements Typical Airplanes Boeing 737-800 MD-82 Airbus 320 Heaviest Airplane Antonov- Multileg Landing Gear Response measured Stress and strain response to main gear

Typical Loading Conditions Take-off and Landing Speed over sensors: 30–190 km/h Average aircraft weight: 63-74 tons

Typical Responses Boeing 737-800 - Landing 100 km/h

Typical Responses MD-82 - 31 km/h

3-D Finite Element Modeling 15 3-D Finite Element Modeling 3-D FE model is used to capture Non-uniform contact pressure Moving tire load Implicit dynamic analysis Viscoelastic HMA layer Infinite boundaries More details can be found in the literature published by Al-Qadi’s group.

Calculated vs Measured Pressure for Truck Loading at 10 km/h 3/26/08 Calculated vs Measured Pressure for Truck Loading at 10 km/h Uniform Tire Pressure Non-Uniform Tire Pressure 20

Calculated vs Measured Pressure for B737 Loading at 190km/h 3/26/08 Calculated vs Measured Pressure for B737 Loading at 190km/h Uniform Tire Pressure Non-Uniform Tire Pressure

3/26/08 Summary Cagliari airport runway pavement was instrumented with 149 sensors New instrument installation techniques were successfully implemented and data was collected from: LVDT’s HMA strain gauges Pressure cells Thermocouples Pavement response data was compared to FEM analysis results

3/26/08 Summary Calculated pressure is lower than measured values near-surface. The difference becomes smaller with depth Non-uniform contact pressure needs to be considered in further analysis

3/26/08 Future Research Continue analyzing data under various loading conditions Calculate pavement responses under realistic tire-pavement contact stresses and compare results to field measurements

3/26/08 Thank You Questions?