The CBDG has set up a Task Group to develop guidance on the design and construction of Integral Bridges. Its aim is to produce best practice guidance sheets on key aspects to clarify some of the current issues concerning this form of construction. Initially the Task Group is putting particular emphasis on the geotechnical aspects of Integral Bridges, although the study will not be limited to this and other issues will be addressed over time.

TRL have been commissioned in 2004 to undertake a research programme for the Task Group which entails the installation of computer loggers at three different sites to monitor the changes in lateral earth pressure with deck temperature over a year

The Task Group has brought together experts from across the industry. As well as the members on the Task Group, other leading bridge and geotechnical engineers will contribute to the activities and assist in developing the guidance sheets.

The members of the Task Group are:

• Steve Metheringham (Scott Wilson) - Convenor
• Alan Bloodworth (University of Southampton)
• Derek Carder (TRL Ltd)
• John Lane (TRL Ltd)
• Prof. Marcus Lee (University of Southampton)
• Neil Loudon (Highway Agency)
• Tony Masters (Posford Haskoning)
• Paul Saunders (Flint and Neill)

The scope and issues to be considered include the following:

1. Review of existing information, research and design guides
2. Investigate of the different structural forms for integral abutments
3. A review of current practice
4. Design guidance for soil pressure on different types of integral abutment
5. Design guidance on settlement of soil behind different types of integral abutments
6. Identify where further research is needed
7. Soil/structure interaction in the design
8. Use of flexible layers
9. Criteria for maximum skew and deck length
10. Robustness of different structural forms
11. Backfill material
12. Software used
13. Soil pressures with cohesive material
14. Maintenance issues
15. Assessment of existing integral bridges
16. Semi-integral bridges
17. Run-on slabs

The committee is currently awaiting relevant information on the implementation of Eurocode EN1992-2 before proceeding further.