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AN INSTRUMENT FOR MEASURING POST ANCHORAGE PERFORMANCE. Vittorio Giavotto – LIRA srl Marco Anghileri - Politecnico di Milano. Purpose. Push tests on barrier posts Static and dynamic tests Acquisition of force and displacement data Tests on posts on-site
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AN INSTRUMENT FOR MEASURINGPOST ANCHORAGE PERFORMANCE Vittorio Giavotto – LIRA srl Marco Anghileri - Politecnicodi Milano
Purpose • Pushtests on barrierposts • Static and dynamictests • Acquisition of force and displacement data • Tests on posts on-site • Driving and extractingposts
Dynamic test on hard soilDynamic test on soft soilDriving and extracting post
Technical dataSelf propelling pole driver plus post testing equipment Static test Force 70 kN Stroke 1600 mm Dynamic test Ram mass 365 kg Max. velocity 12 m/s Useful stroke 600 mm Impact energy 26 kJ Transducers 2 component load cell Accelerometers Position transducers Data acquisition 8 channels Max sampling rate 100 kHz Storage capacity4 Gb
Testing Dynamic: The ramispushed to a high velocity by two air cylinders Static: the ramisslowlypushed by onehydrauliccylinder
Problems in dynamictests • The post must be accelerated to the speed of the ram in a fewmillimeters • Post acceleration can easily go over 1000 g • High oscillations are initiated in the post • Post oscillations and post inertia force introduce high disturbances in measurements • A post in a realbarrierisnotaccelerated so abruptly: veicle and raildeformationallowcentimeters fo the acceleration of the posts
Dynamic test(2100 frame/s) • Visible bending oscillations of the post • The cableactivating the displacementtransducergoesslack • Measurements are difficult to use • Low pass filteringdoesnot help
Dynamic test with a honeycombcushion • Post oscillations are stronglyreduced • The cable of the transducerremainsalmoststraight • The strain rate and the deformation of the post are notaffected
Comparison of static and dynamictests on identicalposts, HE100A S275JR, boltedon a rigiddeck
Future activity- Research • Tests of differentposts in differentsoils • Behaviour of soilsatdifferentvelocities • Differencebetweenstatic and dynamic behaviour • Correlation of post pushparameters with alternative measurements • Development and calibration of numericalmodels for soil post interaction
Future activity – Technical support • Qualification of soils for barrierinstallation • Data base for soil–post iinteractions • Validation of post depthincreaseas a compensation of soilweakness • Verification of anchorage performance • Contribution to the improvement of standards
Conclusions • The new instrumentis a veryeffectiveaid for research on soil-post interactions • Itcan be usedalso to measure ultimate barrieranchorageloads on bridge decks • The use of some kind of cushion in dynamictestsisstronglyrecommended • The results of the researchactivitywill be available to TG1