Adapting the FlexiArch for widening a complex arch bridge

The 1840's Teewell Hill arch bridge, in the suburbs of Bristol, UK, was no longer adequate for increasing local traffic levels and needed to be widened. Several widening options were considered and it was concluded that the innovative ‘FlexiArch’ would best accommodate the complex geometry of the existing structure while minimising social and economic impacts. In order to elegantly accommodate the raked spandrel walls of the existing bridge Macrete and WSP|Parsons Brinckerhoff worked collaboratively to produce a custom-designed, high-quality, precast concrete FlexiArch, which matched the contours of the existing bridge. As the FlexiArch system has no corrodible reinforcement, it is highly sustainable and will result in reduced maintenance, as for the existing bridge. The elimination of centring and speed of construction (hours not months) minimised disruption to road traffic and to cyclists on the cycle network below the bridge – a key project criterion required by the client. Thus, in addition to addressing an accident black spot, the FlexiArch solution provided South Gloucestershire Council (the client) with an aesthetically pleasing and fully functional solution at a competitive cost.