Effects of Steel Flexible Tracks on Forwarder Peak Load Distribution: Results from a Prototype Load Test Platform

Steel flexible tracks (SFT) are regularly installed on bogie axles of forwarders to improve traction
and extend trafficability by increasing the contact area between machines and operating surface.
The study quantified dynamic peak loads exerted by a forwarder driving either on wheels or
using additional SFT on its rear bogie axle. To examine load distribution of a full-scale forwarder,
a load test platform was designed and constructed. Three scenarios were tested with the
forwarder unloaded and loaded to quantify load distribution between wheels driven directly over
the steel load test platform (Scenario 1) and SFT when either driven directly over the steel load
test platform (Scenario 2) or when driven over a 20 cm layer of sand placed over the platform
(Scenario 3). The platform proved to be an appropriate measuring device for full-scale tests.
Results indicate that, when operated on the sand layer, SFT (installed on the forwarder’s rear
unloaded axle) decreased dynamic peak loads by about 30% compared to wheels. The use of SFT
on bogie axles of forest machines is recommended to lower soil disturbances, especially through
a reduction of peak loads often responsible for negatively altering soil physical properties.