I have previously discussed the evidence for a temporary timber and earth rampart with associated infrastructure which necessarily predated and facilitated the construction of Hadrians Wall in stone, it follows that there was probably a temporary bridge where it crossed the North Tyne at Chollerford, [Chesters].
In addition, unlike a timber bridge built on piles, theconstruction of a Stone bridge also requires significant temporary works, whichare evident from the air. In the context of Hadrians Wall there are two aspects tothe crossing of the river; A carriageway for road trafficThe continuation of the barrier across the riverThe surviving bridge abutment on the east bank has twophases;An original structure, presumably Hadrian’s, only 3m wide wasdesigned to carry the wall;A second and more massive phase, thought to date from the refurbishmentaround 160 AD, built to carry both the Wall and the Military Way.
The evidence from the bridge abutment prompts the question where was road bridge in the initial for plan Hadrians Wall?
I have already suggested that the Vallum was dug as a foundation for a road behind the Wall, since this flat bottomed trench follows the ideal course for a road with the spoil moved with enormous effort to facilitate two lanes on either side of a metalled carriageway. Like much of the ambitious initial plan, it was abandoned following the Dislocation – a break in the work presumably caused by warfare.
In addition, it might be presumed there was an initial timber phase of bridge to carry the Military Way, not to mention some form of barrier across the river corresponding to the temporary wall. These defencive works would necessarily be to the north of the Bridge Abutment, while the temporary bridge was perhaps between the between the Wall and the Vallum.
Another factor would have been any existing bridges in the area, it is presumed that earlier East – West Stanegate road crossed the North Tyne a little further downstream.
Continued at Theoretical Structural Archaeology.