Analytical pavement design using programs for personal computers

This paper describes various personal computer programs developed for use in analytical pavement design. In the late 1960s, Shell Research Ltd developed the BISTRO (BItumen STructures in ROads) and BISAR (BItumen Stress Analysis in Roads) mainframe computer programs for research purposes. As a first step towards a 'total design method' for use on a personal computer, Shell Research has developed BISAR-PC, for highway engineers to use in conjunction with the Shell Pavement Design Manual (SPDM) (see IRRD 243568); to make BISAR-PC easier to use, it has two peripheral programs, BISPREP and BISSHOW, to prepare input and to display both input and output. The next step has been the development of three BANDS (Bitumen and Asphalt Nomographs Developed by Shell) programs, to facilitate the generation of appropriate input data and the interpretation of results, such as the maximum stress or strain in the bituminous layers; the nomographs include those for bitumen stiffness, mix stiffness and mix fatigue. The completion of the 'total design system' is expected within a few years; it will enable engineers to: (1) produce pavement designs of increased accuracy more rapidly; (2) assess the effects of variations in individual components on predicted performance in practice. (TRRL)