The new A96 Blackburn and Kintore bypass is scheduled to be officially opened at the end of the month and included in it are four overbridges designed for contractor Balfour Beatty by Scott Wilson.
The contract required that bridge decks were integral with the substructure where possible, and for a family of structures to be created.
Three of the overbridges are integral, while the fourth has a conventional deck with movement joints and bearings. All three integral structures are two-span reinforced concrete slabs built in to reinforced concrete piers and abutments. The spans vary in length from 16 to 19m over the A96 dual carriageway and have modest skews ranging from 8 to 14. The deck slabs are 1m thick with edge cantilevers.
The one conventional bridge has square spans of 17.5m. The skew of the bridge is approximately 41 and as such was outside the range suitable for integral construction.
Reader enquiry no 802