Free Download of : Lecture # 6 Design Loads
The primary design parameter for highways are truck loadings. The American Association of State and Highway Transportation Officials (AASHTO), founded in 1914 as AASHO, developed the concept of a train of trucksin the 1935 that imitated the railroad industry’s
standards. However, as the weight of the trucks grew, the bridges were overstressed.
In 1944, AASHTO developed a new concept: hypothetical trucks, called the H(with twoaxles) and the HS(with three-axles) classes of trucks. These were fictitious trucks, used only for design and they did not resemble any real truck on the road ……..