Flexiarch Bridge Systems

“FlexiArch” bridges are a modern way of constructing arched masonry bridges without the need for centring, internal steel supports or mortar as required by older, traditional arched bridges. This new and innovative system of constructing arched bridges was developed and patented by Queen’s University Belfast’s School of Civil Engineering and Macrete.

FlexiArch bridge systems use much the same principles as a traditional stone masonry bridges, but they are made using modern precast concrete methods. Individual precast concrete tapered blocks are connected by a polymeric flexible membrane which does not require any mortar. The arch falls into shape when craned into position and is self-supporting by virtue of its own weight. The use of the membrane instead of traditional mortar helps to prevent internal corrosion, rebar expansion, and concrete cracking or spalling.

Doran Consulting has utilised this new and innovative FlexiArch system on various commissions to date, including:

• Beragh Bridge Widening, Beragh Village: We were commissioned to provide design services for this Design & Build contract for the Roads Service to provide a footway on both sides of an existing twin span masonry arch bridge in Beragh, Co Tyrone. The design comprised a twin span FlexiArch unreinforced concrete bridge, on both the upstream and downstream sides, supported on reinforced concrete piers and abutments on piled foundations to the underlying rock levels.
• Mullagh Bridge, A2 Kilkeel, Co. Down: We were commissioned to undertake a Category 3 design check on this FlexiArch construction, which had been used here to extend the width of the arch barrel of this masonry arch bridge. This included assessing the arch barrel with an arch analysis software package (RING 3.0) and making amendments to the waterproofing details to improve its aesthetic and durability.
• Global Point Bridge, Global Point Business Park, Newtownabbey: We were responsible for undertaking a Category 3 design check on this FlexiArch construction, used here as a new build arch bridge. This included assessing the arch barrel with an arch analysis software package (RING 3.0) and checking the retaining wall design against BS EN 1990, 1991, 1992 & 1997.