ABSTRACT
Norway has a long history of deflection measurements on the road network, including Benkelman Beam (BB), Dynaflect (DF), LaCroix Deflectograph and single- and two-mass Falling Weight Deflectometer (FWD). Except FWD, all these are merely discontinued. For all these equipment types, measurements are performed point by point, except for LaCroix normally at a 50 m interval, and the center deflection only (BB and LaCroix) or the center deflection with some measure of surface curvature (DF, FWD) has been used with AADTH to calculate a bearing capacity value. Though intended for network level measurements, the capacity of these types of equipment is limited, and the most relevant use is for measurements at project level. Despite network measuring devices like the Traffic Speed Deflectometer, TSD, has been around for several years, no measurements have been performed in Norway with this type of equipment until fall 2015. Then, measurements were performed with a TSD from Poland on some 600 km at low and high volume roads in the south-eastern part of the country. At some of these roads, FWD measurements were also carried out. For these concurrent sections, TSD and FWD measurements are compared, and the BB and FWD methodology is used to calculate bearing capacity for the TSD measurements, with astonishing similarity. The most promising methodology is then used to calculate TSD bearing capacity for the sections without FWD measurements, and the values are compared to other indicators of pavement performance like rutting and unevenness.
