*** ARCH *** is a specialist masonry arch analysis program for both highway and rail bridges, based on the Mechanism Method but also providing facilities to carry out Modified MEXE Method analysis and, by seamless link to the parallel program *** ANALYSE ***, to undertake Pippard/MEXE frame analysis. The output from *** ARCH *** also provides the necessary information for multispan analysis. Like all Cascade programs, *** ARCH *** is designed to be easy to understand and use, with a maximum of visible reference information on-screen and a minimal need for reference to the program manual. Graphical views are available at any time at the touch of a key, and results printouts are as neat and informative as we can make them.

*** ARCH *** is directed primarily at bridge authorities and consulting engineers engaged in assessing masonry or unreinforced concrete arch bridges. It is designed specifically to respond to the requirements of the Highway Agency's Standards BD 21, BA 16 and BD 37, and Railtrack's Standard RT/CE/C/015, but it can also be used to assess bridges carrying other types of loading specified by the user. Version 4.6 is updated in accordance with BD 21/01.

*** ARCH *** was developed and tested over several years by Crouch Waterfall & Partners and was the first computer program for the application of the Mechanism Method to the analysis of masonry arches to be recognised by the then DoT. It has been substantially upgraded and extended in line with updated Standards and user experience since its initial launch as Version 2 in 1991.