The Hemington Bridges : the excavation of three medieval bridges at Hemington Quarry, near Castle Donington, Leicestershire

The Hemington Bridges formed an important medieval crossing point over the River Trent, carrying the King’s Highway linking Leicester and the south to Derby and northern England. This report presents the results of the excavations and multi-disciplinary investigations of three successive bridges found during quarrying operations between 1993–1998, and places the structures in their technological, geomorphological, environmental and historical contexts. The earliest bridge at Hemington, Bridge I, was constructed in the late 11th century and rebuilt in the early 12th century following a calamitous flood. It is the most complete Saxo-Norman timber structure found in Britain and presents unique evidence for vernacular timber working in this period, as well as providing significant information regarding early bridge design and construction techniques. The late 11th-century phase comprised two timber caisson pier bases and a trestle spanning part of a braided channel. The caisson pier bases were large, lozenge-shaped, jointed wooden boxes filled with sandstone rubble, positioned in the river bed, the long axes parallel to the flow. These served as plinths, supporting a superstructure that elevated the decking. The span between the piers was approximately 10m, with the trestle providing a mid-pier support. The trestle provides some important evidence for the superstructure showing that the bridge decking was 2.8m wide, so suitable for carts, and was carried 5.5m above the river bed. It is notable that there are joints preserved in the trestle that have no known parallels. This phase of the bridge was short-lived with evident undermining of the foundations by deep scouring, probably during severe flood conditions. One caisson had rotated laterally by some 808 and the second had tilted from the horizontal by 408. Both had settled into deep scour features, and the trestle had collapsed over one of the caissons. Coarse deposits quickly buried the remains. Sometime after 1111, the bridge, or at least this section, was rebuilt. The second phase of construction comprised a double row of irregularly spaced oak piles with lateral bracing, each pair 2.90m apart, spanning 27m of river channel. Some pairs had supplementary posts, presumably added as alterations or repairs. All the posts had rotted off above the height of the modern water table and consequently no jointing survived to suggest how these posts articulated with the bridge decking. These remains too were buried by coarse, point bar deposits as the river migrated laterally to the south, scouring away the southern bridgehead. The exact timescale for these channel changes is uncertain, but the establishment of Bridge II in the late 12th century suggests that it should be measured in decades. Bridge II was located upstream from its predecessor, and comprised a double row of piled posts with lateral bracing. This was probably constructed in the late 12th century and had been maintained into the 13th century, suggesting that Bridge III was its direct replacement. Bridge III was constructed in the mid 13th century immediately upstream from Bridge II. The first part of the bridge, found in 1993, comprised the foundations of four regularly spaced piers crossing a 50m section of an old course of the Trent. Two different foundation techniques were employed for the piers: those closest to the northern bank were of masonry, constructed directly on the river bed. The two mid-stream piers were hexagonal enclosures of deeply driven piles infilled with sandstone rubble, forming a foundation for a masonry pier, the collapsed remains of which were located on the river bed and in scour features downstream. Associated timber structures included three or possibly four inter-pier structures, probably supports for a timber superstructure, and a baffle located in front of the mid-stream piers. The piers and baffle were constructed from timber felled in the late 1230s and early 1240s. Further structural activity or maintenance is shown by the presence of a timber felled c. 1270–1305 in one of the inter-pier structures. The southern abutment of the bridge was revealed in further quarry work in 1998. A corresponding, but unrecognised, northern abutment was probably observed during quarrying in 1991–2