Robert Stephenson had bridged the River Conwy (1848) and the Menai Straits (1850) with spans of 400 and respectively, using large box-girder sections of riveted wrought iron. Conwy-like box-girders would have been very expensive to use at Chepstow as well as being heavy (problematic, since the spans had to be lifted much higher than at Conwy). Brunel, characteristically, sought a radical solution. He had already built a bowstring or tied arch bridge at Windsor (1849) consisting of three triangular cross-section cellular arch ribs "strung" by wrought iron deck girders supported by vertical hangers from the arches. This was the same year as Stephenson's tied arch High Level Bridge at Newcastle upon Tyne, which was supposed to have influenced Brunel at Chepstow. However, Brunel's solution for the latter was to make a leap forward, based, nevertheless, on sound engineering principles and a variation of the tied-arch theme.