A34 Chieveley/M4 junction 13 improvement: design

The project involved the grade separation of the A34 at junction 13 of the M4 motorway and was carried out under a design-and-build contract. Three integral bridges with contiguous pile wall abutments and Y-beam and slab decks were designed for construction in a top-down sequence while maintaining three lanes of traffic in each direction on the M4. This paper describes the design process, including derivation of earth pressures on the integral abutments, analysis of the soil–structure interaction and the global analysis of the structure. Comparison is made between the design methods required by BD 42/00 which embodies CIRIA Report 104 and the recently published CIRIA C580, and matters pertaining to the design of integral bridges with frame and embedded type abutments are identified for discussion.