Effects on in-service pavements from super-heavy overloads weighing over 2, 000, 000 pounds are investigated. A field study was performed in which a crack survey was conducted, pavement deflections weremeasured using a dynaflect before and after overload transport, andseveral instruments were deployed to measure surface deflection when the overload traversed the pavement. The field study also characterized materials, determined dimensions of structural layers, and measured wheel loads applied to the pavement. Measured deflections are compared to predictions that are based on models used for flexible pavement design. Results of crack surveys show no change in the visible condition of the pavement after transporting the overloads. Dynaflect measurements after transport were approximately equal to pavement deflections measured before hauling the overloads. In-transit deflection measurements show that a "big basin" results from widely distributed trailer axle/tire loads. Deflections from tractor tires were not substantially different from those caused by trailer tires. Measured in-transit deflections agree reasonably well with maximum displacement predicted using elastic layer models. This paper appears in transportation research record no. 1196, Pavement evaluation and rehabilitation.
Abstract