Generally speaking Highway Design Engineers are well served by the protocols set out in the Design Manual for Roads & Bridges (D.M.R.B.) which provides guidance on total pavement thicknesses. The DMRB is supported by a number of documents that provide guidance on material selection. However these methodologies have two major limitations: they are restricted to busier trunk roads with traffic levels above one million standard axles and the material options are confined to those stipulated in The Specification for Highway Works.
These issues provide a challenge to the Design Engineer working on more lightly trafficked pavements that are subjected to different vehicle movement patterns. There are several documents available that provide guidance for these other pavement constructions but being aware of these and selecting the most appropriate can be confusing. My career history means that I am well placed to assist in this process, helping the engineer select the most appropriate pavement build up to suit the scheme and his clients requirements.
Areas of assistance include:
- Establishing pavement build up designs, including those for Sustainable Drainage Systems (SuDS).
- Advising on the selection of appropriate materials (both standard and proprietary) and highlighting the benefits & risks associated with each.
- Advising on the practicality or ‘buildability’ of the selected design.
- Some design requirements mean that the design engineer cannot always provide a perfect solution, I can assist in highlighting these sensitivities so that the end client is fully aware of the issues & limitations of his new pavement.
- Advising on the production of a set of standard build-ups that can be used for less complex applications.
- Sense checking designs and making sure that the selected materials are specified correctly, thus ensuring that the material chosen by the engineer is actually used on the scheme.