BISAR software

The original BISAR mainframe computer program was developed by Shell (De Jong et al. 1973) in the early 1970s, which was used in developing the design charts of the Shell Pavement Design Manual. An abbreviated version for use on a personal computer was issued in 1987 (Koole et al. 1989) and the final release of BISAR 3.0 for use in the Windows environment replaced the DOS version BISAR-PC 2.0 (Shell International 1998). 

BISAR 3.0 is a computer program for the calculation of stresses, strains and deflections for a variety of loading patterns. It is also able to deal with horizontal forces and slip between the pavement layers. 

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Figure a.17 Typicai notations and numbering of iayers and interfaces used by the BiSAR software. 

The nomographs were developed using the principles of the elastic layered system where materials are characterised by their stiffness and Poisson s ratio. The stresses and strains developed were calculated using BISAR software (de Jong et al. 1973) incorporated in Shell s pavement design software SPDM-PC (Valkering and Stapel 1992). 

For the determination of the critical strains in the asphalt layer and subgrade, the equations given in Sections 13.2 and 7.7.3 have been used. For the strains developed in the pavement structure, the in-house BISAR software was utilised to develop the design charts. 

Some of the most widely used computer software developed to calculate stresses, strains and displacements in flexible pavements with the use of the multi-layered elastic theory are CHEVRON, BISAR, ELSYM5, KENLAYER and WESLEA. 

A new layered elastic analysis program, called MNLAYER, is claimed to be more accurate than JULEA, especially at evaluation points located close to the surface or at large depths. Since, for the same structural system, it requires less computational time than JULEA and BISAR, MNLAYER is an attractive candidate for incorporation into the MEPDG software (Wang 2008). 

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