Applicability of portable tools in assessing the bearing capacity of forest roads

Forest roads provide access to logging sites and enable transportation of timber from forest to mills.�Efficientforestmanagem entandforestindustryareimpossiblewithoutaproperforest � roadnetwork. �Thebearingcapacityofforestroadsvariessignificantlybyweatherconditions � and seasons since they are generally made of poor materials and the constructed layers may be mixedwithsubgrade. �Abearingcapacityassessmentisvaluableinformationwhentrafficability � isuncertainandruttingisobvious. �Inthisstudy , �bearingcapacitymeasurementswerecarriedout � usingthelightfallingweightdeflectometer �(LFWD), �thedynamicconepenetrometer �(DCP) �and � thec onventionalf allingwe ightd eflectometer �( FWD).�T hea imwa st oc omparet heirm easurement� results in relation to road characteristics and moisture conditions. Data were collected from 35 test road sections in four consecutive springs and during one summer. The test road sections had measurement points both on the wheel path and the centre line. The data show logical correlations betweenmeasuredquantities, �andthestudypresentsreliableregressionmodelsbetweenmeasuring� devices.�Theresultsindicatethatlightportabletools, �theDCPandtheLFWD, �caninmostcases � beusedinsteadoftheexpensivefallingweightdeflectometeronforestroads. Keywordsstif fness; �lightweightdeflectometer; �dynamicconepenetrometer; �fallingweight � deflectometer; �elasticmodulus Addresses 1 �NaturalResourcesInstituteFinland, �Greentechnology , �Kaironiementie �15, �FI-39700� Parkano,�Fi nland;� 2 �T ampereUni versityofT echnology, �P.O.Box �60 0, �FI-33 101�T ampere, �Fi nland