CEN/TC226/WG1/TG1 Linkoping June 14, 2011 AN INSTRUMENT FOR MEASURING POST ANCHORAGE PERFORMANCE...

CEN/TC226/WG1/TG1 Linkoping June 14, 2011

AN INSTRUMENT FOR MEASURINGAN INSTRUMENT FOR MEASURINGPOST ANCHORAGE PERFORMANCEPOST ANCHORAGE PERFORMANCE

Vittorio Giavotto – LIRA srlVittorio Giavotto – LIRA srl

Marco Anghileri - Politecnico di MilanoMarco Anghileri - Politecnico di Milano

PurposePurpose

• Push tests on barrier Push tests on barrier postsposts

• Static and dynamic Static and dynamic teststests

• Acquisition of force Acquisition of force and displacement and displacement datadata

• Tests on posts on-Tests on posts on-sitesite

• Driving and Driving and extracting posts extracting posts


Dynamic test on hard Dynamic test on hard soilsoilDynamic test on soft Dynamic test on soft soilsoilDriving and extracting Driving and extracting postpost


Technical dataTechnical dataSelf propelling pole driver plus post testing equipmentSelf propelling pole driver plus post testing equipment


Static testStatic testForceForce 70 kN70 kNStrokeStroke 1600 mm1600 mm

Dynamic testDynamic testRam massRam mass 365 kg365 kgMax. velocityMax. velocity 12 m/s 12 m/sUseful strokeUseful stroke 600 mm600 mmImpact energyImpact energy 26 kJ 26 kJ

TransducersTransducers2 component load cell2 component load cellAccelerometersAccelerometersPosition transducersPosition transducers

Data acquisitionData acquisition8 channels8 channelsMax sampling rate 100 kHzMax sampling rate 100 kHzStorage capacity 4 GbStorage capacity 4 Gb

TestingTesting


Static:Static:the ram is slowly pushed the ram is slowly pushed by one hydraulic cylinderby one hydraulic cylinder

Dynamic:Dynamic:The ram is pushed to a The ram is pushed to a high velocity by two air high velocity by two air cylinderscylinders

6 posts dynamically tested6 posts dynamically tested


Problems in dynamic testsProblems in dynamic tests

• The post must be accelerated to the speed of The post must be accelerated to the speed of the ram in a few millimetersthe ram in a few millimeters

• Post acceleration can easily go over 1000 gPost acceleration can easily go over 1000 g• High oscillations are initiated in the postHigh oscillations are initiated in the post• Post oscillations and post inertia force Post oscillations and post inertia force

introduce high disturbances in introduce high disturbances in measurementsmeasurements

• A post in a real barrier is not accelerated so A post in a real barrier is not accelerated so abruptly: veicle and rail deformation allow abruptly: veicle and rail deformation allow centimeters fo the acceleration of the postscentimeters fo the acceleration of the posts


Dynamic testDynamic test(2100 frame/s)(2100 frame/s)

• Visible bending Visible bending oscillations of the postoscillations of the post

• The cable activating the The cable activating the displacement displacement transducer goes slacktransducer goes slack

• Measurements are Measurements are difficult to usedifficult to use

• Low pass filtering does Low pass filtering does not helpnot help

Dynamic test with a Dynamic test with a honeycomb cushionhoneycomb cushion

• Post oscillations are strongly Post oscillations are strongly reducedreduced

• The cable of the transducer The cable of the transducer remains almost straightremains almost straight

• The strain rate and the The strain rate and the deformation of the post are deformation of the post are not affectednot affected

Future activity - ResearchFuture activity - Research

• Tests of different posts in different soilsTests of different posts in different soils• Behaviour of soils at different velocitiesBehaviour of soils at different velocities• Difference between static and dynamic Difference between static and dynamic

behaviourbehaviour• Correlation of post push parameters with Correlation of post push parameters with

alternative measurementsalternative measurements• Development and calibration of numerical Development and calibration of numerical

models for soil post interactionmodels for soil post interaction


Future activity – Technical supportFuture activity – Technical support

• Qualification of soils for barrier installationQualification of soils for barrier installation

• Data base for soil–post iinteractionsData base for soil–post iinteractions

• Validation of post depth increase as a Validation of post depth increase as a compensation of soil weaknesscompensation of soil weakness

• Verification of anchorage performanceVerification of anchorage performance

• Contribution to the improvement of Contribution to the improvement of standardsstandards


ConclusionsConclusions

• The new instrument is a very effective aid for The new instrument is a very effective aid for research on soil-post interactionsresearch on soil-post interactions

• It can be used also to measure ultimate It can be used also to measure ultimate barrier anchorage loads on bridge decksbarrier anchorage loads on bridge decks

• The use of some kind of cushion in dynamic The use of some kind of cushion in dynamic tests is strongly recommendedtests is strongly recommended

• The results of the research activity will be The results of the research activity will be available to TG1available to TG1


CEN/TC226/WG1/TG1 Linkoping June 14, 2011 AN INSTRUMENT FOR MEASURING POST ANCHORAGE PERFORMANCE...

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